Vegetables & Fruit November/December 2023 by Vegetables & Fruit

SINCE 1988

NOVEMBER • DESEMBER 2023

National mapping of macadamia and yield forecasting (BTW ingesluit) ander lande uitgesluit VAT) other countries excluded No 216 R44,00 (Including

SWEET MELON & WATERMELON RANGE COLORSWEET COLORSWEET

SWEET SWEET SPRING SPRING

• Ideal for spring and summer season •• Ideal spring and summer season Early for maturing •• Early Brightmaturing orange, firm flesh •• Bright orange, firm flesh High brix •• High Goodbrix disease resistance • Good disease resistance

• Medium to large, very uniform fruit •• Medium large, very season uniform fruit Ideal for to early to main •• Ideal for early to main season Attractive medium to fine net •• Attractive medium to finefornet Firm, orange flesh ideal whole fruit and • Firm, orange flesh ideal for whole fruit and fresh-cut • fresh-cut Resistance to Fusarium and Powdery • Resistance to Fusarium and Powdery Mildew Mildew

GOLDELIXIR GOLDELIXIR

TOUCHDOWN TOUCHDOWN

• Ideal for early and late season •• Ideal early and well late season Largefor oval-round, netted fruit with no • Large ribbingoval-round, well netted fruit with no • ribbing Deep orange, firm flesh with long shelf life •• Deep orange, fleshtaste with long shelf life High brix and firm excellent •• High brix and excellent taste Strong disease resistance package • Strong disease resistance package

• Bright orange, firm flesh •• Bright flesh package Strongorange, diseasefirm resistance •• Strong resistance package Large todisease Extra-Large fruit size of 4.0 – 5.0 kg •• Large to Extra-Large fruit size of 4.0 – 5.0 kg Ideal for late season and winter fresh • Ideal for late season and winter fresh market • market Medium to course developed net with • Medium to course developed net with slight ribbing slight ribbing

TALCA TALCA

ESSENCE ESSENCE

• Ideal for summer and early season •• Ideal early seedless season fruit Largefor to summer medium, and uniform, •• Large to medium, uniform, seedless fruit Deep red, crisp flesh with long shelf life •• Deep red, and crispexcellent flesh with long shelf life High brix taste •• High brix vines and excellent taste Vigorous with high yield • Vigorous vines with high yield

• Ideal for summer season •• Ideal summerseedless season fruit Large,for uniform, •• Large, uniform, seedless Deep red, very crisp flesh fruit with long shelf life •• Deep red, and veryexcellent crisp flesh with long shelf life High brix taste •• High brix and excellent taste Very vigorous vines with high yield • Very vigorous vines with high yield

Edition 215

ISSN 1015-85 37

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COVER Macadamia producers have faced numerous challenges this past season, but the future is promising.

EDITORIAL Willie Louw (Group editor) Carien Daffue (Editor) 082 927 8294 018 293 0622 info@mediakom.co.za PO BOX 20250, Noordbrug, 2522 ADVERTISING Jana Greenall 011 476 3702 082 780 9914 mediacom@lantic.net DESIGN Mercia Venter studio.chatnoir@gmail.com

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The importance of transforming the ‘right way’ in SA’s agri sector Christo van der Rheede retires after eight years at Agri SA New dean for natural and agricultural sciences at UFS Citrus Growers’ Association welcomes Maydon Wharf development SA citrus industry closes EU exports Giant leap for hunger in SA through food donation regulations Dutch agri companies take educational tour of Joburg Fresh Produce Market Sagtevrugtebedryf steier onder vloedramp

10 12 14

If you only sit on the side and look on, nothing will ever change Controlling stink bugs on avocados Increase set and yield in avocado

Groente & Vrugte | Vegetables & Fruit

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Macadamias explores new markets Converting macadamia nectar into honey already begins at the flower National mapping of macadamia and yield forecasting

GENERAL 22 23 24

Unieke chemie en voordele vir aartappelmot 10 Ways to encourage fresh produce consumption Supply chain disruptions highlighted at IFPA conference

26 28

Management of irrigation in onion production The effect of pre-harvest application of Crop4Life on fungal decay in Cape gooseberries (Physalis peruviana)

VEGETABLES & FRUIT | NOVEMBER • DESEMBER 2023

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NEWS

The importance of transforming the ‘right way’ in SA’s agri sector W

andile Sihlobo, Chief Economist at Agbiz, has shed light on the future of South African agriculture in a recent interview on the "What's Treading" podcast. Sihlobo, who has closely observed the complexities within the country’s agricultural sector over the past several decades, emphases that while transformation is essential, the focus must be on growth and not redistribution. The agri sector is marked by its two faces: large-scale commercial farmers and struggling small-scale black farmers. With the latter producing between 10% to 15% of the country's commercial output, Sihlobo advocates for a comprehensive growth approach rather than a mere shift of resources. "Expanding the agricultural pie for everyone is where the focus should be. Instead of redistributing, we should be looking at how we can tap into underutilised areas and truly realise the potential of our fertile lands," said Sihlobo. He also stressed the importance of local governance in facilitating this growth. Many of South Africa’s farming communities are affected by smaller municipalities' inefficiencies.

Bridging the gap between policy and its implementation is pivotal for the sector’s success. However, Sihlobo remains optimistic about the sector. “I am very hopeful for the future of South Africa’s agricultural sector. It is one that will be transformed by renewables, technology innovations, and inclusive policies. It is also a sector that can create a million jobs by 2031. It is also a sector that can grow in value by anything from 30% to 50% to harness the untapped potential that lies hidden in the country’s fertile soil.” He also cited the African Continental Free Trade Agreement as an example of where opportunities can be had. “Our agriculture is export-oriented with markets in the East and West, as well as within the BRICS community offering significant demand. If these dreams are to be realised, we must collaborate. Heads must come together, not in conflict but in unity. We need to map a clear path forward. Yes, it is a challenge, but the immense promise that uplifting our farming communities means we must persevere,” he said.

New dean for natural and agricultural sciences at UFS

Christo van der Rheede retires after 8 years at Agri SA

he University of the Free State (UFS) has appointed Prof Paul Oberholster as dean of the faculty of Natural and Agricultural Sciences as of 1 January 2024. He will succeed Prof Danie Vermeulen and is currently the director of the centre for environmental management at the UFS. After several years in secondary edu- Prof Paul cation, Prof Oberholster started his scien- Oberholster. tific research career as a senior scientist at the Council for Scientific and Industrial Research (CSIR) where he became a chief scientist, managing large multidisciplinary projects on the African continent related to integrated water resource management and natural-based treatment solutions/ecological engineering. During his time at the CSIR, he acted as professor and lecturer in several academic departments at different institutions. During the same time, he received several presti gious awards for research, innovation, and leadership. Prof Oberholster joined the UFS in 2019 and received a National Science and Technology Foundation award. In 2023 he was appointed as the Managing Director of the Ecological Engineering Institute of Africa (EEIA). “It is a privilege to be part of the leadership team in the faculty. We will ensure that the faculty is known nationally and internationally as an excellent faculty serving our community,” says Prof Oberholster.

s Agri SA prepares for the retirement of CEO Christo van der Rheede, incoming CEO Johann Kotze has come on board full-time to continue to ensure a smooth leadership transition. Agri SA is grateful for Van der Rheede’s contribution to the organisation and service to farmers. “Van der Rheede took the lead at a time of great uncertainty and was immediately able to reassure farmers and rebuild trust. His regular engagements with farmers’ associations and study groups were well received, enabling him to keep his finger on the pulse of the sector and to stay in touch with the issues that are important to farmers. “His passion for agriculture and the agricultural value chain has resulted in many interventions which, with hard work and perseverance, have led to positive outcomes. It was in part thanks to his tenacity and capable advocacy, for example, that the restrictions brought about by the Covid-19 pandemic, which directly and negatively affected the agricultural sector, were reversed and the sector was recognised as an essential industry.” As his successor, Johan Kotza brings a wealth of experience. Kotze has himself been a farmer before working in agricultural and corporate banking. His tenure at Agri SA follows six years as the Chief Executive Officer at the South African Pig Producers Organisation (SAPPO). Recognised for his creativity and innovative leadership, Agri SA looks forward to continuing to execute its mission with a leader of his calibre at the helm.

VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

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Citrus Growers’ Association welcomes Maydon Wharf development T

ransnet’s request for proposals to develop a multi-purpose terminal for citrus and other fruit handling purposes at the Port in Durban’s Maydon Wharf area has been welcomed by the Citrus Growers’ Association (CGA). The Maydon Wharf precinct is approximately 145 hectares and boasts 15 common-user berths and an annual cargo capacity of over 7 million tons, according to Transnet. South Africa’s citrus-producing capabilities are a marvel enjoyed across the globe and is considered the secondlargest exporter of citrus products behind Spain. The high demand for South African fresh produce is, however, not being fully used to the country’s advantage. While South Africa exports citrus goods like oranges to almost 100 countries, the European Union (EU) is the biggest customer, accounting for around 40% of total foreign sales, according to a report by the United States Foreign Agricul-

ture Service. The EU has, however, ordered that citrus exports undergo specified cold treatment processes and pre-cooling steps to prevent citrus black spot and false codling moth. The CGA welcomes the news that Transnet is seeking private investors to build and operate a terminal at its Durban port to export citrus and other fruit. The steps Transnet has taken in recent months towards public-private partnerships at ports and on the Durban-JHB rail line are encouraging and a reason to be cautiously optimistic. Projections are that, if all role-players work together, an additional 100 million cartons of fruit can flow from pack houses to ports over the next nine years, growing to 260 million. This means the industry could potentially sustain a further 100 000 jobs and generate an additional R20 billion in annual revenue, bringing its contribution to 240 000 jobs and R50 billion.

SA citrus industry closes EU exports T

he Citrus Growers’ Association of South Africa (CGA) and the Fresh Produce Exporters’ Forum (FPEF) announced the conclusion of the 2023 orange exports to Europe. As the South African citrus season in Europe came to a natural end recently, floating consignments of approved oranges had time to reach destinations in Europe. The CGA and FPEF’s announcement also allows the northern hemisphere to take advantage of current excellent market conditions. It is in a spirit of budding cooperation with European citrus producers, notably in Spain, that the South African industry now hands over the handling of citrus demand to the northern hemisphere. Consumers worldwide, including Europe, have shown an exceptional appetite for South African citrus. The local industry has not been able to fill the demand by European orange consumers this year.

Considering the challenges growers have had to face during the 2023 season - which included continued load shedding, unusual weather and logistical strain at ports and on rail - the CGA and FPEF wants to thank growers, exporters and other industry role-players for their continued productivity and commitment to an industry that supports 140 000 livelihoods. As ever, the CGA and FPEF remain committed to working with government and other value chain partners to ensure local growers can withstand the current economic headwinds.

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FoodForward SA’s Second Harvest programme enables farmers to donate surplus harvest.

Giant leap for hunger in SA through food donation regulations “Within the next year we are hoping to have national food donation regulations in place that would enable us to recover far more good, edible surplus food that is currently going to waste every year, and which can feed the millions of hungry people in our country,” says Andy du Plessis, the managing director of FoodForward SA (FFSA), the largest food redistribution non-profit organisation in South Africa.

fter years of appealing to the national government to put food donation regulations in place, this is finally happening in collaboration with the relevant departments, including the department of Health, which is the guardian of the Food Act. Du Plessis explains that 10 million tons of food goes to waste every year in South Africa and ends up in landfills due to various supply chain dynamics (July CSIR 2021 technical report on food loss and waste). That is a third of the 31 million tons produced annually in South Africa. A huge percentage of this is good, edible and healthy food. “FFSA is recovering less than 1% of the 10 million tons of surplus food that goes to waste every year,” he says. “We distribute it through 2 750 registered non-profit and beneficiary organisations that collectively reach 985 000 vulnerable people throughout South Africa every day. We have received catalytic support from the WWF Nedbank Green Trust, funded by Nedbank, which has contributed to FFSA’s supplier and farmer network expansion since 2020.

“FFSA has a string of regular suppliers, including food manufacturing corporations, food retail chains and farmers, with more coming on board every month,” says Poovandran Pillay, of Nedbank. “However, many others have said that their organisations do not allow them to donate perishable or nonperishable foods without a policy in place because of liability concerns or uncertainty. Putting a policy in place would be a giant leap for addressing hunger in South Africa.” With clear regulations in place, Du Plessis says that over the next 5 years, FFSA could scale up to deliver edible surplus food to more than 2,5 million vulnerable people and increase their beneficiary organisation network to between 3 500 and 5 000 nationally, as they have branches in all nine provinces. “We met with the departments of Health, Trade and Industry, and the Consumer Goods Council of South Africa and proposed our recommendations for regulatory changes to reduce food loss and waste and increase food security. These were then presented to the National Economic Development and Labour Council’s (Nedlac) Cost of Living Rapid Response Team.”

VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

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FoodForward SA Northern Cape warehouse.

10 million tons of food goes to waste every year in South Africa and ends up in landfills due to various supply chain dynamics. Subsequent meetings included the Harvard Law Schools food law and policy clinic and the legal resources centre about international best practice on food donations. Recently the department of Health visited FFSA’s head office in Cape Town and was impressed by their scale of operations. They have called for submissions for labelling guidelines, and invited FFSA to submit comments on food donations and make it clear that food past its “Best Before” date can be donated. “The Department of Health is now looking at these submissions and updating the guidelines. They have indicated that they will publish the guidelines in the coming months,” Du Plessis explains. “The second piece of good news is that we have engaged the South African Bureau of Standards to put together a South African National Standard (SANS) for food safety guidelines for food donations. They estimated that this may take between 8 and 12 months to complete. This will significantly change the food donations environment.” Over 95% of the food donated to FFSA is nutritious, including fruit, vegetables, yoghurt, milk, cheese, cereals and canned goods like baked beans, as well as protein sources such as pilchards. Many of these foods are unaffordable for millions of South Africans who mainly eat cheaper starches like maize meal. Through their “Second Harvest” programme and with support from the WWF Nedbank Green Trust, FFSA has, over the past three years, expanded its donating farmer network. “In 2019 we had 15 farmers, that grew to 34 in 2020 and we then formed a partnership with OneFarm Share that has a network of more than 600 farmers donating agricultural produce into our network,” says Du Plessis.

Food loss in SA According to WWF, in South Africa, 49% of all agricultural production is lost or wasted due to a number of factors, including post-harvest surplus harvests, specification requirements, cold chain and processing inadequacies or farmers not having access to markets. FFSA collects from the farmers while they harvest. Weather was named as one of the biggest causes of food loss, including sun damage to fruits, and wind or hail damage. Defects caused by weather lead mostly to cosmetic damage to the fruit and vegetables, where the skin or peel might have blemishes or discolouration and often cannot be sold despite the flesh being edible and of a high quality but often cannot be sold. The farmers said that because of the high transport costs this food often goes to waste or ends up as animal feed rather than being donated because it’s just too expensive to

VEGETABLES & FRUIT | NOV • DES 2023

arrange the transport. With FFSA collecting from their farms, they are more than willing to donate. The only remaining stumbling block now is the section in the Consumer Protection Act around strict liability. Under the current regulations, if a company donates food to FFSA who onward donates that food to a beneficiary organisation, the originator of the food may still be held liable. This is obviously a limiting factor for donations. “We are proposing that if the food is deemed safe at the time of donating it to us − we have a strict checking list and operating procedure to determine this − then liability must end at the point at which the food is donated,” says Du Plessis. “In the same vein, once we have donated food to our beneficiary organisations and it is deemed safe, we should no longer be liable. We are in discussions with the department of Trade and Industry on this.” Du Plessis says FFSA has all the infrastructure and logistics in place to significantly scale up once the food donations regulations have been put in place. “We have a fleet of refrigerated trucks that enables us to collect surplus food and deliver it to vulnerable communities across the country. We are ready to go”.

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Dutch agri companies take tour of Joburg Fresh Produce Market Dutch agricultural companies toured the Joburg Fresh Produce Market to learn more about South Africa’s unique free market approach to the fresh produce value chain.

RSA Group CEO, Jaco Oosthuizen, showing Dutch delegates around the Joburg Fresh Produce Market.

ecently, the Embassy of the Kingdom of the Netherlands in South Africa facilitated a tour of the market (JFPM) for leading Dutch agribusinesses. The purpose of the tour was to introduce the Dutch delegates to the workings of the market, focusing specifically on the unique commissioned-based system used. “The direct sales and wholesale approaches currently utilised internationally are noteworthy for their low transparency levels, and the fact that product is owned by individual entities rather than primary agri brands,” explains Emiel Mulder, from the Embassy. “Conversely, the South African system is a neutral trading platform featuring high visibility, with prices discovered daily on the basis of current supply and demand factors. This allows agribusinesses of different types and scale to compete and grow their own brands, while servicing all South African consumers, including the millions of citizens who access fresh produce via informal trade networks.” The tour included conversations with producers, sales agents, market management and others who are essential to the day-to-day running of the market at different fruit and vegetable floors. They shared personal reflections on working in the agricultural industry, how the industry functions, and how their own careers have grown within it. “The tour was followed by a great session at the RSA Group offices at the JFPM, where RSA Group CEO, Jaco Oosthuizen, offered the party an excellent, detailed overview of how South Africa’s fresh produce markets ecosystem functions,” says Mulder. “There were many fascinating insights on offer, and the group also appreciated the opportunity to hear from Wandile Sihlobo, Chief Economist of the Agricultural Business Chamber

of South Africa, and to receive copies of both of his books.” Another unique feature of South Africa’s National Fresh Produce Markets is their status as a transparent value transfer mechanism able to convert fresh produce harvests into revenue that goes back to farmers, as well as to local authorities, in the form of sales commissions. To the uninitiated, converting a harvest into revenue may sound like a natural part of farming, but this aspect of agribusiness is actually highly complex, with many farmers struggling to establish a reliable sales channel mix that allows them to sell all their produce in a predictable, sustainable way. While most global governments incur significant subsidy costs to secure their national fresh produce value chains and ensure farmers are offered enough incentives to keep producing, the South African free market fresh produce system functions very effectively in this regard, at no cost to the state. “Our system is very different to Europe and the USA, and international visitors are always interested in finding out more about how we do it,” says Oosthuizen. “It has been an absolute pleasure to guide our Dutch friends through our different processes and systems, and to introduce them to the incredible members of our fresh produce community. “South Africa is a major fresh produce exporter and has strong and important relationships with fresh produce businesses across the world, especially in Europe,” concludes Oosthuizen, who is also the International Fresh Produce Association Southern Africa country council chairperson. “Interacting with global agribusinesses in forums like this is vital to the health and vibrancy of our community, and the trade reception was another excellent opportunity to strengthen key relationships and take our industry forward.”

VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

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Sagtevrugtebedryf steier onder vloedramp HORTGRO

ie Suid-Afrikaanse sagtevrugtebedryf steier onder die impak van die onlangse oorstromings in belangrike produk- siegebiede, veral in Elgin, Grabouw, Vyeboom en Villiersdorp (EGVV), dele van die Klein Karoo en Franschhoek. Tydens ’n krisisgesprek met die Wes-Kaapse Departement Landbou (WKDL) blyk dit dat die aanvanklike impak van die skade aan infrastruktuur tussen R400 tot R500 miljoen, net in die EGVV area, kan beloop. Die sagtevrugtebedryf is die grootste landboukommoditeit wat in die streek verbou word. Die WKDL het ’n selfoontoepassing geloods in ’n poging om kontak te maak met produsente wat skade gely het. Voorlopige data wat hierdeur ingesamel is, van 26 produsente in Grabouwstreek, dui daarop dat vloedskade in die omtrek van R160 miljoen beloop. Dit sluit nie Villiersdorp en Vyeboom in nie. Infrastruktuurskade sluit in skade of vernietiging van: kragnetwerke, boorde, netstrukture, geboue, masjinerie, besproei ingstelsels en -toerusting, besproeiingskanale, asook paaie en brûe wat weggespoel het. Nog reën het boonop verdere skade veroorsaak. Talle paaie en brûe op plase self, is totaal weggespoel. Hortgro se uitvoerende direkteur, Anton Rabe, sê dat bogrond

en talle boorde ook in die slag gebly het. “Die produksieseisoen wat nou in alle erns begin, is erg ontwrig met spuitprogramme, asook bestuiwing, wat nie volgens skedule verloop nie en in die voorsiening van kritiese insette soos diesel.” Van groot belang is om belangrike toegangspaaie en brûe in so mate te herstel dat produsente hulle werkers op die plase kan kry en steenvrugprodusente wat oor ’n paar weke begin oes, hulle vrugte by die markte kan kry. Daar is ook talle pakhuise in die EGVV vol kernvrugte bestem vir die uitvoermark, wat by die hawe moet kom, het Rabe gesê. Die herstel en vervanging van besproeiingskanale, waterpype en -pompe is krities om die seisoen te probeer red. Kragtoevoer en selfoonopvangs is nog nie 100% herstel nie, wat dit logisties moeilik maak om hulp te verleen. Glaudi Skog, EGVV-landbou verteenwoordiger, het gesê die humanitêre nood in die streek is groot, met verskeie gemeenskappe wat kos en drinkwater benodig. Hortgro het reeds R250 000 aan die Gift of the Givers geskenk wat kospakkies en ander nooditems in die onderskeie streke gaan versprei. Daar word ’n beroep op die publiek gedoen om verdere skenkings aan Gift of the Givers te maak, om die mense van die EGVV en ander vloedrampgebiede by te staan.

The marketing and editorial team of

wishes you

a wonderful festive season and blessed new year VEGETABLES & FRUIT | NOVEMBER • DESEMBER 2023

SUBTROPICAL FRUIT

If you only sit on the side and look on, nothing will ever change This year saw the return of the AllesBeste symposium held in Tzaneen. Industry specialists and delegates in the avocado industry came together to once again discuss the industry and participate in discussions around new research and practices.

llesbeste is famous for the Maluma avocado, a darkskinned cultivar with an immaculate appearance and astonishing taste - researched and developed by the Allesbeste nursery. Its texture is smooth and ideal for any recipe. It has a nutty taste with characteristics like small seeds with more flesh, purple-black thick skin, and smooth and light fibre. Allesbeste Boerdery made great strides in commercialising the Maluma avocado, which has over the past 23 years been successfully introduced to Peru, Spain, Israel, Brazil, Argentina, Chile, the USA, Portugal, Morocco, Egypt, India, Tanzania, Zambia, Zimbabwe, Mozambique, New Zealand and Australia. Worldwide Maluma plantings have reached 5 200 ha and South African growers have established 2 570 ha of Maluma avocados in the country of origin.

Ethylene Jorge Garcia and Lianne Jones from It’s Fresh along with Donovan Lewis, marketing manager for Allesbeste, discussed intelligent ethylene control at the symposium. “One of the biggest problems to solve is not only to bring the fruit to its final destination, but landing quality fruit that is able to ripen full of flavour and give consumers the experience that they were hoping for,” said Lewis. Ethylene is a plant hormone that induces ripening and deterioration in fresh produce and it is produced by most fresh produce. There is a wide variety in the amount of ethylene

emitted across all fresh produce types, as well as the level of sensitivity to this hormone. Too much ethylene, and fresh produce is at risk of becoming overripe. Too little, and the normal biochemical pathways are inhibited. Riper fruit produces more ethylene and triggers surrounding fruit, therefore, managing ethylene is essential in extending the shipping/storage life and quality of fresh produce. However, certain methods negatively impact fruit ripening, flavour, texture, and nutrition. It’s Fresh uses their own product called - It’s Fresh Active. It is formed of natural minerals, which are applied and integrated with different types of packaging. Ethylene molecules in the air around the fruit are drawn to Active, binding to its unique honeycomb structure. The technology reduces the concentration of ethylene in the air around fruit, reducing ripening rates it is highly versatile and can be applied at every stage of the fresh produce supply chain and is food contact approved.

Data and technology Edrean Ernst and Jandré Killian from RIC Consulting led a session discussing technology, benchmarks and measurement. One of the important issues that was discussed is that, having a lot of different subsystems from different providers/ platforms, is not a problem and should be seen as a good approach. The issue that should be addressed is that the information is properly interpreted and displayed on a dashboard

The Maluma avocado, a darkskinned cultivar with an immaculate appearance and astonishing taste - researched and developed by the Allesbeste nursery.

10 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

SUBTROPIESE VRUGTE

Zander Ernst from Allesbeste, Mary-Lu Arpaia from the University of California and Dr Guy Witney.

Zander Ernst from Allesbeste, Jandre Killian from RIC Consulting and Edrean Ernst from Allesbeste.

where the information can be pulled together. “Data that are fragmented across different farming support systems can be pulled together to be displayed on meaningful dashboards. Allesbeste accomplishes this through their farm management system, called Root, as well as the Qlik Business Intelligence platform, supported by RIC Consulting,” Ernst mentioned.

Variety selection Mary-Lu Arpaia from the University of California and Dr Guy Witney discussed avocado breeding and selection. They shared their views and insights on the future of avocado varieties and where they believe the next paradigm shift will lie with avocado varieties. They discussed the challenges of breeding new avocado varieties. It is a long process - growers look at between 15 to 25 years from seed to commercialisation. It is like looking for a needle in a haystack and the success rate is very low, because finding both the horticultural and fruit traits in a single selection is challenging. The fruit must be ripened in order to evaluate; ripening time depends on maturity. The eating quality changes throughout the season; it takes a lot of work to find the optimum maturity window for selection. Industry standard ‘Hass’ sets a high standard for postharvest and eating quality. “As growers we need to understand that the market will only move on new cultivars if we actively plant them, and we need these genetics to improve our position in the market. Single cultivar production threatens long term sustainability and we have to believe actively that there is a world beyond that,” said Arpaia.

Zander Ernst from Allesbeste, Hantie Muller from Agri Librium and Dr Christo Malan from the University of Stellenbosch.

Orchard practises Dr Christo Malan from the University of Stellenbosch, Hantie Muller from Agri Librium and Dr Steve Oosthuyse from HortResearch SA discussed orchard practices and nutrition and shared some of their research findings. Malan spoke about efficient nutrient utilisation and ion charge management in orchards. Muller, who visits growers regularly, shared her insights on some general mistakes growers make in young orchards and when in production. Zander Ernst from Allesbeste gave feedback on their trel-

Lianne Jones from It’s Fresh along with Donovan Lewis, marketing manager for Allesbeste, Zander Ernst and Jorge Garcia.

lising and ultra-high-density experiments, using the Maluma variety in Tatura and vertical trellis systems. He says that in terms of production so far, the Tatura system has proven more successful while vertical systems are easier to manage. He led panel discussions after the presentations.

VEGETABLES & FRUIT | NOVEMBER • DESEMBER 2023

SUBTROPICAL FRUIT

CONTROLLING stink bugs on avocados The stink bug.

vocado farming has become more popular due to the increasing global demand for this nutrient-rich fruit. However, with growth comes challenges, and one such challenge is the threat posed by stink bugs. These notorious pests not only damage avocado crops through feeding but also diminish the quality of the fruit, impacting both yield and economic returns. To counter this issue, Villa Crop Protection has yet again turned to innovative solutions, one of which is the use of spirotetramat, the active ingredient in TIVOLI 240 SC. Spirotetramat is a highly systemic insecticide offering stink bug control while maintaining the ecological balance.

Deciphering spirotetramat's mechanism of action Spirotetramat belongs to the keto-enol class of insecticides and boasts a mechanism of action that sets it apart from traditional chemical treatments. It operates as a systemic insecticide, meaning it is taken up by the avocado tree and distributed throughout its vascular system. This property enables spirotetramat to reach various plant tissues, including stink bug feeding and reproducing areas. At the heart of spirotetramat's effectiveness lies its unique ability to disrupt chitin biosynthesis - a vital process for the growth and development of insects. Chitin is a key component of insect exoskeletons and plays a critical role in maintaining their structural integrity. By interfering with chitin production, spirotetramat leaves stink bugs vulnerable, hindering their ability to moult and grow. Consequently, this disrupts their life cycle and curtails population growth.

Prolonged protection: The systemic nature of spirotetramat provides a longer-lasting shield against stink bugs. Since the insecticide remains active within the plant for an extended period, it safeguards the avocado trees against stink bug infestations throughout critical stages of fruit development. Resistance management: Over time, pests can develop resistance to commonly used insecticides, rendering them ineffective. TIVOLI 240 SC’s novel mode of action offers a fresh approach, as stink bugs are less likely to have developed resistance to this specific class of insecticide. Sustainable agriculture: With the global emphasis on sustainable farming practices, the product aligns well with the principles of integrated pest management (IPM). By minimising harm to non-target organisms and reducing environmental impact, spirotetramat contributes to a more ecologically balanced agricultural ecosystem.

Guidelines for successful application While TIVOLI 240 SC holds promise as a powerful tool in stink bug management on avocados, its effective application is crucial for optimal results. Following recommended guidelines for dosage, timing, and application methods is essential. Rigorous adherence to these guidelines ensures that spirotetramat’s benefits are fully realised, providing enhanced protection for avocado crops while safeguarding the environment.

A holistic approach to pest management

ADVANTAGES Selective impact: Unlike broad-spectrum pesticides that harm various insects indiscriminately, TIVOLI 240 SC’s targeted mechanism of action minimises the impact on non-target organisms, including beneficial insects and pollinators. This preserves the ecological balance in avocado orchards, fostering a healthier farming environment. Residue management: Traditional chemical pesticides can leave residue on produce, raising concerns about consumer health and environmental contamination. TIVOLI 240 SC’s systemic action mitigates these concerns, resulting in lower residue levels on the harvested avocados.

Consider TIVOLI 240 SC as part of a comprehensive pest management strategy rather than a standalone solution. Combining this product with cultural practices, biological control agents, and regular monitoring can significantly amplify its impact on stink bug populations. By adopting a holistic approach, farmers can maximise spirotetramat’s efficiency while minimising the potential for resistance development. In conclusion, TIVOLI 240 SC use to control stink bugs on avocado trees represents a significant stride in modern agriculture. Its innovative mode of action, which disrupts chitin biosynthesis, offers a targeted and sustainable solution to the persistent challenge posed by stink bug infestations. By embracing spirotetramat within an integrated pest management framework, farmers can ensure healthy avocado orchards, higher yields, and a more resilient agricultural future. Visit www.villacrop.co.za for more products and information.

External damage due to late stink bugs.

Internal damage due to late stink bugs.

Registration details: TIVOLI 240 SC: Reg. No. L 9385 Act No. 36 of 1947. Active ingredient: spirotetramat (tetramic acid) 240 g/l. Warning: May cause an allergic skin reaction. Causes serious eye irritation. May cause respiratory irritation. Suspected of damaging fertility or the unborn child. Toxic to aquatic life with long lasting effects. Registration holder: VILLA CROP PROTECTION (PTY) LTD. Co. Reg. No. 1992/002474/07. PO Box 10413, Aston Manor, 1630. Tel. 011 396 2233

12 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

Products. Insights. Expertise. TIVOLI 240 SC. Active ingredient: spirotetramat (tetramic acid) 240 g/ℓ, Reg. No. L 9385, Act 36 of 1947. Company registration details: Villa Crop Protection (Pty) Ltd. Reg. No. 1992/002474/07, PO Box 10413, Aston Manor, 1630. Tel. (011) 396-2233 Warning: May cause an allergic skin reaction. Causes serious eye irritation. Suspected of damaging fertility or the unborn child. Toxic to aquatic life with long lasting effects. Read the label before use.

www.villacrop.co.za

SUBTROPICAL FRUIT

Increase set and yield in AVOCADO A

n interesting fact of the avocado is that the flowering is alternate dichogamous. That means that male and female flower parts open and close at different times of the day. Certain cultivar groups have female flower parts (anthers receptive to pollen) opening in the morning and male flower parts (stamens shedding pollen) opening in the afternoon, while other cultivar groups are exactly vice versa. Because of this and only under ideal flowering conditions, self-pollination is not possible in single-cultivar orchards. Fortunately, conditions are not always ideal and therefore some overlapping of the opening of male and female flower parts often occurs, resulting in self-pollination. Cross-pollinators, of the “vice-versa” cultivars, are sometimes interplanted in an orchard to facilitate the pollination issues. Bees are agents of pollination. Flower primordia are initiated and can be found at the terminal or sub-terminal buds on current seasons' growth flushes after growth cessation. The primordia develop into multibranched panicles which hold more than 1 000 flowers. Of these flowers, only two may permanently set fruits that season (normally about 1 in 500). Fruit drop normally occurs in a 7075 day period following fruit set. The fruit growth is typically sigmoidal and arbitrarily divided into three phases. The first growth stage (approximately 74 days - cultivar Fuerte) starts slowly. This is the stage when most of the fruit drop occurs. Only about 14% of the final size occurs during this stage. The second stage of rapid growth occurs after fruit drop is completed. In the cultivar Fuerte this stage is about 137 days and contributes to about 80% of final fruit size. Optimum growing conditions and nutrition are required during this stage to ensure a good fruit size. Stage 3 begins when the seed reaches maturity and the natural physiological (maturation) processes kick in. In Fuerte this is about seven months after fruit set. Cell division slows and only a further 6% in fruit size is added in the next month or two. The fruit, a typical berry fruit, has a high oil content (only surpassed by the olive), a high dry matter content, and the protein and mineral contents are two to three times that of most commonly sold fruits. Avocados require deep well drained soil of 1,5 to 2 m deep. Soil physical inspection followed by a soil analysis is required at least a year before proposed planting. Any lime applications need to be made preferably 12 months in advance. Deep soil preparation, to effective rooting depth, is required to ameliorate with lime and correct any physical limitations. Annual leaf sampling during the autumn (shoot growth cessation) is important to fine-tune fertiliser recommendations. Leaves for analysis should be taken from non-bearing branches without active shoot growth. Typical of horticultural fruits and vegetables, the potassium requirement is higher than all the other elements. Avocados also take up magnesium in greater quantities than many other crops. Zinc nutrition is important in avocados. Horticultural practices that facilitate the uptake of the essential cation elements of potassium, magnesium, calcium and zinc will ensure sufficiencies for growth and yield.

Source: Zikah, S. et al (2000)

Supplying nitrogen in the nitrate (anion) form facilitates this uptake due to electrochemical potentials being maintained in the roots. For a 20 000 kg avocado crop, the estimation regarding nutrient removal is: 56 kg N, 21 kg P, 134 kg K, 22 kg Mg, 11 kg Ca, 40 kg S, 234 g Fe, 44 g Mn, 772 g Zn, 288 g Cu and 1966 g B. Avocado roots do not have root hairs. Absorption takes place through the tissue close to the root tips of secondary roots. The roots are sensitive to excess salts which can result in root damage as well as leaf burn. Applying all the tree’s potassium (K) requirements as potassium chloride or potassium sulphate can result in induced salinity around the roots. Although sulphur (S) is an essential element, the application of potassium sulphate exclusively as the potassium source will supply up to double the required sulphate which causes excessive root-zone salinity. Using potassium nitrate makes sense as both N and K elements are required by the plant with no residual salts remaining. The nitrate in the potassium nitrate also helps to optimise the nitrate-nitrogen application which, as described above, synergistically enhances the uptake of the most essential cations (K, Mg, Ca, Zn). In field grown horticultural crops, aim for a 75:25 percent nitrate to ammonium ratio for nitrogen applied. Alternate bearing in avocado is often ascribed to tree carbohydrate reserve fluctuations between years. Nitrate nutrition in many crops has been noted to enhance carbohydrate accumulation because of the N conversion process. Nitrate is primarily metabolised in leaves using light energy while ammonium nitrate is metabolised exclusively in the roots by burning carbohydrate as energy. By using potassium nitrate (Ultrasol K Plus* and Qrop K**), the grower will optimise nitrate nutrition, optimise tree carbohydrate status while also ensuring the synergistic uptake of the high cation requirements. This will result in regular yields of good quality fruit. *Reg No K5020 Act 36/1947. Registration holder Sociedad Quimica y Minera (Africa)(Pty)Ltd **Reg No K5021 Act 36/1947. Registration holder Sociedad Quimica y Minera(Africa)(Pty)Ltd DISCLAIMER: The information herein contained is given to the best of SQM’s knowledge and is believed to be accurate. The conditions of use and application of the suggested recommendations, are beyond SQM’s control. No warranty is made as to the accuracy of any data or statements contained herein. SQM specifically disclaims any responsibility or liability relating to the use of the recommendations and shall under no circumstances whatsoever, be liable for any special, incidental or consequential damages arising from such use.

14 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

MACADAMIA

Macadamias explores new markets In the ever-challenging world of agriculture, the macadamia industry in South Africa has gone from strength to strength. Lizel Pretorius, Chief Executive Officer of Macadamia South Africa NPC (SAMAC) discusses some of the challenges and highlights of the macadamia industry in South Africa.

ccording to Pretorius the industry has been facing some challenges since last year. This is mainly due to China being in hard lockdown because of Covid, but this initiated some opportunities. For some years now, globally there has been a higher demand than supply of macadamias - a favourable situation for producers because of higher prices. South Africa’s 2023 crop of 77 523 tonnes is higher than the 2022 crop of 68 840 tonnes. Compared to the 2022 crop, the industry’s production increased by 8 692 tonnes in 2023. South Africa continues to maintain its position as the largest macadamia-producing country in the world, a title that it has held for many years. However, because of the higher supply other market opportunities are presenting themselves. Markets like the ingredient market and the nutrition market have been coming to the foreground. This will have a positive impact on the overall macadamia industry as soon as exports go back to normal. Food manufacturers are now starting to use macadamias in their products, due to their nutrient-rich nature. The World Macadamia Organisation (WMO) is running a communications campaign to increase awareness of macadamia’s increased supply and why it is worth reconsidering them in future formulations and product offers. Pretorius mentioned that the WMO is running a global marketing campaign aimed at consumers about building the love of macadamias, called ‘Love Macadamia’. Love MacadamiaTM was launched in the middle of 2022 and now features across three websites and six social channels, tailored to the specific needs of the USA, China and Indian consumers. Each country uses the same core elements and they are adapted for the specific cultural environment. India is a significant market for nut consumption, however, macadamias are not well known at all. Research led to focus activities on women, 30-40 years old, who actively care about their own and their family’s health. The programme wanted these women to discover macadamias, often for the first time, and to incorporate it into their regular food choices because they understood it would help with health and wellness objectives. These women often take advice from nutritionists, and both talking to nutritionists and having nutritionists credibly

share the macadamia story, was important. The focus was put on Delhi, and have in place a programme that includes macadamias being featured at lifestyle events, lots of health-orientated influencers sharing experiences of macadamias, articles in aspirational publications, and building social channels that now have 10 000 followers after only five months. The United States is the biggest snacking market for macadamia kernels and there is still a lot of potential to grow. The Love Macadamia movement is targeting health-conscious millennials, who often are aware of macadamias but these nuts are not part of their regularly consumed healthy food set. While the USA is a big country, the epicentre of Love Macadamia activities is in California. The key elements of the USA activities have been digital advertising to drive people to the website, reinforcing a clear health message focusing on good fats, and creating online communities and activities. The programme focuses on growing the overall macadamia category and is partnering with consumer brands that have macadamia offers to amplify communication. China is an example of a market that has grown from limited volumes to a very significant one in 10 years, consuming about 50 000 MT mostly in nut-in-shell format. Love Macadamia was introduced in China in late 2022 and talks to both the nut-in-shell and kernel consumer. Kernels is more for on-the-go and regular consumption, and health credentials support this positioning. The key element of the programme in China is a Weibo channel which has grown to 116 000 followers. The first activity of the WMO in China was a campaign to bring more warmth to the nut-in-shell moment, encouraging super moms to create special family moments involving macadamias around festivals and rituals. In addition to the Chinese New Year, there are lots of special occasions and through testing a few, it was found that the national holiday occasion had the biggest new consumer engagement in macadamias. Pretorius concluded that the future for macadamia producers is bright. No matter what, macadamia has one secret weapon and that is its nutritional value, which means that there will always be a need for macadamias. .

16 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

Protect Your Macadamia Nut Crops INSECTICIDES

A foliar-applied insecticide for control of a wide range of sap feeding insects.

KEY ATTRIBUTES AND ADVANTAGES Broad spectrum of activity against many sap-feeding insect pests.

Valuable rotation partner with other insecticide chemistries.

Effective at low use rates.

Minimal impact on beneficial insects, including bees and natural enemies, when label directions for use are followed.

Excellent knockdown, fast feeding cessation and long residual control. Excellent translaminar and xylem systemic activities.

Rapidly degraded in the environment. Metabolites are of low toxicity to bees and beneficials.

Effective against insect pest populations resistant to other classes of insecticides.

A water dispersible granule contact and stomach insecticide.

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KEY ATTRIBUTES AND ADVANTAGES Provides long-lasting control of a broad spectrum of insect pests in a variety of crops. Applied at low rates.

Active by ingestion and contact. JemvelvaTM (spinetoram) penetrates leaves (hastrans laminar activity) to provide control of leaf miner larvae.

Minimal impact on beneficial insects, including bees and natural enemies, when label directions for use are followed. Fits Integrated Pest Management (IPM) programs.

OUR CROP PROTECTION PRODUCTS ARE AT THE HEART OF AGRICULTURE FOR MORE INFORMATION CONTACT THE REGISTRATION HOLDER: Corteva Agriscience RSA (Pty) Ltd · Reg. No. 1997/003030/07 • Paarl +27 (0) 21 003 8259 • Centurion +27 (0) 12 683 5700 • 2nd Floor, Building A, Lakefield Office Park, 272 West Avenue, Centurion, 0157, Gauteng, Republic of South Africa. ALWAYS USE ACCORDING TO LABEL RECOMMENDATIONS: • Closer® 240 SC contains Isoclast® (sulfoxaflor) (240 g/l) | Reg. No. L9694 | Act No. 36 of 1947 • Delegate® 250 WG contains JemvelvaTM (spinetoram) (250 g/kg) | Reg. No. L8392 | Act No. 36 of 1947 • TM ® Trademarks of Corteva Agriscience and its affiliated companies. © 2023 Corteva.

HAZARD STATEMENT(S) FOR CLOSER® 240 SC Very toxic to aquatic life with long lasting effects.

WARNING

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MACADAMIA

Converting macadamia nectar into honey already begins at the flower A study revealed that worker bees save energy by removing water from nectar droplets in flight and reduce their flight energy, while hive bees then need to do less work when dehydrating the nectar to honey. Dr Hannelie Human, Prof Susan Nicolson and Prof Christian Pirk DEPARTMENT OF ZOOLOGY AND ENTOMOLOGY, UNIVERSITY OF PRETORIA MACADAMIA SOUTH AFRICA

oneybees are known to collect nectar over a wide range of sugar concentrations and are dependent on the nectar sources available. Collecting more dilute nectar requires the removal of excess water during the ripening process of honey. We have known for some time that worker bees in the hive repeatedly regurgitate and suck up nectar droplets to remove water. They then fan the nectar inside the honeycomb’s hexagon-shaped cells to remove more water, until the sugar concentration reaches 80% and it can be stored as honey. What we didn’t know, until recently, is that forager bees outside the hive actually already remove most of the water from

nectar droplets at the flower and in flight, before they deli ver their nectar load to the hive a process that simultaneously achieves evaporative cooling of their heads. This also affects communication with fellow foragers about nectar quality. Pollination biologists commonly accepted nectar concentration in forager’s crops to be an accurate reflection, and a convenient sampling method, of the nectar concentration of the flowers. This sampling method needed reconsideration after the report on the elimination of excess water enroute to the hive for Aloe greatheadii var. davyana, an important winter bee plant in South Africa. The relatively dilute aloe nectar (20% w/w) in flowers contrasts with a sugar concentration almost twice as high in the crop contents of returning foragers to the hive. Honeybees were found to remove 57-75% of the water while collecting nectar from Macadamia integrifolia (Proteaceae) flowers, an important nut crop in South Africa. Pollination by honey bees (Apis mellif-

18 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

MAKADAMIA

era scutellata Lep.) contribute to macadamia crop yields and the copious nectar flow result in honey production for beekeepers. Similar to the reports on the aloes, forager crop contents were further concentrated on their return flight to the hive and an average of 81% of the water is already gone by the time they reached the hive. This could only happen if the bees use their tongues to evaporate the water from the nectar by blowing bubbles and swallowing it again. Forager bees were captured on the way back to their hives at a macadamia orchard in the Barberton area. The bees were intercepted before they could hand over their collected nectar to the hive bees. Contents of the bees’ honey stomachs, called crops, were removed and the water and sugar contents were measured and compared to the water and sugar found in the unprocessed nectar in the macadamia flowers. Concerns about the effect of different nectar concentrations between cultivars were ruled out since little variation was reported for the macadamia cultivars used in this study (A4,

695, 814 and 816). The effect of the nectar load on departure was also ruled out as a factor, since the amount of nectar sugar is too small to account for the increase in concentration at the flowers. This nectar load is only used as fuel for flight and for sticking pollen grains together. By removing water, worker bees saves energy in two ways. First, the load they have to take back to the hive is smaller, so flight energy costs for individual forager bees are reduced. Secondly, and more importantly, the colony saves energy and it means that the hive bees need to do much less work when dehydrating the nectar to honey in the hive. The process of nectar dehydration is a very energy costly process with bees using between 25-60% of the sugar in the nectar being brought into the nest. The savings in honey processing costs were calculated to be on average 35 times more than the reduction in flight costs due to the reduced body mass of honeybees. This phenomenon has been observed in aloes and macadamias, but there is no reason why that should be limited to these two plants but rather a general and widespread adaptation to decrease the water in nectar thereby saving energy and of crucial importance for “producing” honey.

Reference Nicolson, S.W., Human, H. & Pirk, C.W.W. Honey bees save energy in honey processing by dehydrating nectar before returning to the nest. Sci Rep 12, 16224 (2022). https://doi. org/10.1038/s41598-022-20626-5.

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LEES DIE PRODUKETIKET VOOR GEBRUIK. CHORUS® (nie beperk nie) bevat siprodinil (analienpirimidien) 500 g/kg (Reg. Nr. L5383, Wet Nr. 36 van 1947) WAARSKUWING. GHS-Gevaarstelling: Baie giftig vir waterlewe met langdurige effekte. CHORUS®, die verwantskapraam, die doelwit-ikoon en die woord Syngenta is geregistreerde handelsmerke van ’n Syngenta Groepmaatskappy. Syngenta Suid-Afrika (Edms) Beperk, Privaatsak X60, Halfway House, 1685. Tel. (011) 541 4000. www.syngenta.co.za © Syngenta Ag, 2000. Kopiereg voorbehou. Alle ongemagtigde vermeerdering word verbied.

@SyngentaSA | www.syngenta.co.za

MACADAMIA

National mapping of macadamia and yield forecasting Under a Macadamias South Africa NPC (SAMAC) initiative, researchers at the University of New England’s Applied Agricultural Remote Sensing Centre (AARSC) have completed the national map of all commercial macadamia orchards across South Africa. The total production area of macadamia orchards mapped across South Africa is 72 652 ha. Craig Shephard APPLIED AGRICULTURAL REMOTE SENSING CENTRE, UNIVERSITY OF NEW ENGLAND MACADAMIA SOUTH AFRICA

he mapping delivers an accurate understanding of the extent (distribution and area) of macadamia plantings. No grower or commercial information are collected or included. This foundational information is essential to inform traceability and forward selling, support biosecurity preparedness and for post-natural disaster response and recovery. Knowing where crops are located is vital for timely response to biosecurity incursions, to establish exclusion zones and coordinating onground surveillance, as well as quantifying the area of crops impacted following a natural disaster. Field validation was completed for three provinces, targeting known areas of uncertainty. Many new plantings were observed which added a further 1 461 ha to the map: 342 ha in KwaZulu-Natal, 505 ha in Mpumalanga and 614 ha in Limpopo. This analysis clearly demonstrates the value of field validation, where remote sensing alone (satellite imagery) cannot accurately map new plantings. Industry participation in peer review of the draft map using the Industry Engagement Web App (IEWA) (https://arcg. is/TurWa) has proven highly successful, with 1 027 comments received. This feedback added 3 988 ha of orchards to the map (mostly new plantings), confirmed 2 780 ha were cor-

Table 1: Farm level yield predictions (tonnes, normalised to 100 to keep commercial production data confidential).

Farm number

Yield (normalised)

Yield prediction

Error (%)

100

100,6

0,6

100

101,5

1,5

100

94,1

-5,9

100

109,9

9,9

100

112,1

12,1

100

84,2

-15,8

100

82,0

-18,0

100

131,1

31,1

100

149,0

49,0

100

149,2

49,2

100

199,9

99,9

rectly mapped (macadamia) and removed 2 409 ha that were other tree crops, eg. avocado, citrus, litchi. This engagement is highly encouraging as a project outcome as it demonstrates the greater industry-wide support of SAMAC in the collation of accurate industry data for the betterment of all. The map has been published in the SAMAC Dashboard application (https://arcg.is/1L1X900 , Fig 1). The dashboard is available publicly, and includes functionality to return summary metrics for total area by province, as well as interactively based on the view extent of the user. Instructions are provided, and the researchers have also included a button to support on-going updates to the map which directs viewers to submit feedback using the IEWA if they notice something missing or incorrect in the map. Annual planting of macadamia orchards across South Africa has now been measured at 7 000+ ha/year, since 2019. As such, annual updates are recommended to maintain the accuracy and currency of the map.

Planting year prediction Based on the map extent, AARSC have predicted the planting year of all orchards. To build the model, historical industry data was provided by Mayo Macs and Source B.I as training data (which included orchard planting age), analysed alongside historically acquired time-series Landsat satellite imagery (from 1986 - present). The resulting algorithm produced an average prediction error of ±1,8 years. Applied to all ‘pixels’ within the map extent, AARSC have derived a map of macadamia orchards classified by planting year, which is summarised and presented cumulatively by province in Figure 2. Note the gap between 2019-2021 is due to the coarse resolution of the satellite pixels (30 m) not being able to detect the age of new plantings accurately. Total areas for 2022 are derived directly from the map.

Yield forecasting A methodology for yield forecasting at multiple-scales (originally developed for Australian orchards, Brinkhoff, J. & Robson, A., 2021) was applied to South African orchards. The model, which utilises historic orchard level productivity information as well as publicly available data (satellite, weather, elevation), typically achieves average errors of 25% at the block level and <15% at the farm level in Australia. This varies from farm-to-farm and in the presence of extreme drought or flood conditions. The model was applied to a database of South African maca-

20 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

MAKADAMIA

Figure 1: SAMAC Dashboard, providing interactive summaries.

blocks. As more orchards reach maturity, and higher yields are available in the database, it is likely that prediction performance will continue to improve.

Contact Mapping: Craig Shephard (Senior Researcher, AARSC) cshepha2@une.edu.au Yield and planting year: Dr James Brinkhoff (Assoc. Professor, AARSC) James.Brinkhoff@une.edu.au Other enquiries: Prof Andrew Robson (Director, AARSC). Andrew.robson@une.edu.au

Acknowledgement This project is led by the Applied Agricultural Remote Sensing Centre at the University of New England, Australia (AARSC) with support from Macadamias South Africa NPC (SAMAC).

Figure 2: Total area by predicted planting year by province (cumulative).

damia block yields: 12 farms, 320 blocks, > 1 200 records. Correlations between yield and remote sensing indices were very similar to those in Australia, with the green normalised vegetation index (GNDVI) around the middle of the year being the strongest predictor. Yield predictions were quite accurate for the majority of blocks, but the model tended to under-predict some of the very high yielding blocks (> 4 t/ha). Model prediction errors at the block level tend to cancel when aggregated to the farm level. Table 1 shows the yield predictions for each farm for 2021, using a model developed using only data from before 2020. The production for four farms were predicted with less than 10% error. Farm number 4 had predictions double what was actually achieved, possibly associated to harvest losses from monkeys, as the farm is adjacent to bush lines. If the case, this process could be used to better quantify harvest losses (from a range of influences) and as such better inform if remedial measures are required. In summary, it was found that similar relationships between satellite-derived remote sensing indices and yield in South Africa to those modelled in Australia. Whilst yield forecasts in the South African case were not as accurate as typically achieved in Australia, the methodology shows promise, as it was able to describe much of the variability between low and high yielding

VEGETABLES & FRUIT | NOV • DES 2023

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2024 8 & 9 February 2024 Get your tickets now @ www.quicket.co.za For more information and stand bookings Expo organiser: Andri van den Bergh Tel: 082 3755 109 | Email: andri@ambermacs.com Plot 88, Agri Holdings, Old Plaston/Yaverland Road, White River.

GENERAL

Unieke chemie en voordele vir aartappelmot Aartappels word regoor Suid-Afrika geproduseer en word as ‘n sleutelgewas in groente se produksiemandjie beskou, maar insekplae soos die aartappelmot kan groot oesverliese veroorsaak.

hthorimaea operculella (Zeller, 1873) (Lepidoptera: Gelechiidae), wat ook as die aartappelmot in Suid-Afrika bekend staan, is ‘n generalistiese plaag-insek met ‘n voorkeur vir gewasse soos aartappels, tamaties en tabak. Die aartappelmot se oorsprong spruit uit Suid-Amerika en is reeds vir langer as ‘n eeu in Suid-Afrika teenwoordig waar dit hoofsaaklik warmer gebiede verkies. Klimaatsverandering mag wel lei tot ‘n hoër voorkoms en aktiwiteit van die aartappelmot as gevolg van droër en warmer klimaatstoestande wat verwag kan word. Besmettings deur die aartappelmot kan tot betekenisvolle verliese lei. Larwes wat die blaartonnel binnedring sal gewoonlik nie ‘n beduidende oesverlies hê nie, maar jong plantjies aan die begin van die seisoen mag erge skade onder hoë besmettingsvlakke lei. Wanneer plante se loof aan die einde van die seisoen begin afneem, begin larwes na alternatiewe bronne van voedingsmateriaal soek. Dit is die stadium wanneer ‘n hoë risiko ontstaan, aangesien larwes af kan beweeg en klein openinge asook kra kies op die grondoppervlakte binnedring wat toegang tot knolle bied. Gestoorde knolle kan ook beskadig word indien besmetting plaasvind as gevolg van wyfies wat toegang tot pakhuise kry. Soos met enige plaagbeheer, word die gebruik van geïntegreerde plaagbestuur (GPB) ten sterkste aanbeveel om die aartappelmot te beheer wat omgewings- en ekonomiese aspekte bevoordeel. As deel van ‘n GPB strategie en om die risiko van weerstands ontwikkeling te verminder, is SumiPleo® ‘n goeie keuse om aartappelmot mee te beheer. Dit bevat die chemiese aktiewe bestanddeel, Piridaliel (IRAC groep: UN) wat deur Sumitomo Chemical Company in Japan geïdentifiseer en ontwikkel is. Sleutelkenmerke van SumiPleo® sluit die volgende in: • Unieke chemiese molekuul (dichloopropeen-derivaat) met geen risiko vir kruisweerstand met ander molekules wat tans op die mark beskikbaar is nie. • ‘n Kontak- en maaginsekdoder in ‘n emulgeerbare konsentraatformulasie. • Kort na inname (drie tot vier ure) hou teiken-larwes op vreet. • Dit is doeltreffend teen alle larvale instars. • Dit het ‘n beduidende lae uitwerking teen nie-teikenorganismes soos roofmyte, wespes, kewers, erdwurms en bestuiwers soos bye.

• SumiPleo® het ‘n relatiewe kort onthoudingsperiode op aartappels van 14 dae. • Dit benodig nie bykomende bevorderings- of kleefmiddels nie en beskik oor uitstekende reënvastheid sodra die spuitmengsel op die teikenplant droog geword het. Let wel dat indien die produk teen die aartappelmot aangewend word, kan ‘n 50% tot 80% afname in skade van Liriomyza spp. blaarmyners verwag word. As deel van ‘n strategie binne ‘n spuitprogram om die aartappelmot te beheer en die risiko tot weerstandsontwikkeling te beperk, dien SumiPleo® toe teen 200 ml/ha as deel van ‘n voldekbespuiting in 500 - 1 000 L water per hektaar sodra die pes waargeneem word. Aartappels moet minstens twee keer tydens die seisoen gerif word om die beheer van aartappelmotlarwes te ondersteun. Philagro SA bied eksklusiewe toegang tot SumiPleo®, mo derne insekdoder-tegnologie uit Japan. Vir meer inligting, kontak gerus die naaste Philagro-verteenwoordiger of die produkbestuurder, Jaco Marais - 072 390 3547.

Verwysings CABI DIGITAL LIBRARY. 2021. Datasheet: Phthorimaea operculella (Potato tuber moth). CABI Compendium. https://www. cabidigitallibrary.org/ Datum van toegang: 21 Junie 2023. KROSCHEL, J, SPORLEDER, L. and CARHAUPOMA, P. Pest distribution and risk atlas for Africa - Potato tuber moth, Phthorimaea operculella (Zeller 1873). International Potato Centre. https://cipotato.org/ Datum van toegang: 26 Junie 2023. VISSER, D. 2011. A complete guide to vegetable pests in South Africa. Agricultural Research Council, Roodeplaat Vegetable and Ornamental Plant Institute, Pretoria. 316 pp. SAKAMOTO, N., UEDA, N., UMEDA, K., MATSOU, S., HAGA, T., FUJUSAWA, T. and TOMIGAHARA, Y. 2005. Research and development of a novel insecticide “Pyridalyl”. Sumitomo Kagaku 2005-I. RAADPLEEG DIE VOLLEDIGE SUMIPLEO® ETIKET VOOR GEBRUIK. SumiPleo® (Reg. Nr. L8377 Wet. Nr. 36 van 1947) bevat 500 g/L piridaliel dichlorpropeen-derivaat. GHS (seinwoord): Gevaar. GHS Gevaarverklaringsterme: Mag dodelik wees indien ingesluk en in lugweg beland (aspirasiegevaar). Mag allergiese velreaksie veroorsaak. Veroorsaak oogirritasie. Mag slaperigheid of duiseligheid veroorsaak. Baie giftig vir waterlewende organismes met langdurige gevolge. SumiPleo® is ’n geregistreerde handelsmerk van Sumitomo Chemical Company, Japan. Philagro South Africa (Edms) Bpk. Reg. Nr. 1998/010658/07 PostNet Suite #378, Privaatsak X025, Lynnwoodrif 0040. 012 348 8808 / 021 851 4163.

22 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

ALGEMEEN

10 WAYS to encourage fresh produce consumption

MARIANA PURNELL

fresh produce more engaging.

CONTRIBUTOR

Farm-to-table apps

he recent International Fresh Produce Association (IFPA) Southern Africa Conference in Cape Town emphasised the importance of improving the utilisation of fresh fruits and vegetables to promote better health. Here are some interesting approaches to not only encourage fresh produce consumption but also tackle the perishability factor by providing education, convenience, and creative solutions for utilising produce before it spoils.

Produce subscription boxes with recipes Create subscription boxes that include a variety of fresh produce along with easy-to-follow recipes. This not only introduces consumers to new fruits and vegetables but also provides guidance on how to use them in delicious meals, reducing the intimidation factor of trying unfamiliar produce.

Virtual cooking classes Host online cooking classes that focus on using fresh produce creatively. Invite renowned chefs or nutritionists to demonstrate how to prepare quick and tasty dishes incorporating various fruits and vegetables.

Smart refrigerator apps Develop smartphone apps that connect to smart refrigerators. These apps can track the freshness of produce, send expiration reminders, and suggest recipes based on the ingredients available. This helps consumers use up their fresh produce before it goes bad.

Community gardens with tech integration Set up community gardens in urban areas and integrate technology. Use sensors and apps to monitor plant growth, soil conditions, and hydration levels. Participants can virtually “adopt” plants and receive updates on their progress, fostering a sense of responsibility and connection to the produce.

Augmented reality (AR) shopping Implement AR technology in grocery stores. Shoppers can use their smartphones to scan produce items, and the app provides information about the nutritional value, recipes, and tips for selecting the best pieces. This interactive experience makes shopping for

Develop apps that connect consumers directly with local farmers. Users can pre-order fresh produce from nearby farms, and farmers can harvest accordingly. This reduces the time between harvesting and consumption, thus reducing spoilage.

Food waste reduction challenges Organise social media challenges or apps that encourage users to share their creative ways of reducing food waste. Participants can showcase how they use leftover or slightly ageing produce to create delicious meals, promoting both sustainability and fresh produce consumption.

Virtual reality farmers' markets Create virtual reality experiences that replicate the atmosphere of farmers' markets. Users can "walk" through stalls, interact with virtual farmers, and make purchases. This approach maintains the traditional market feel while overcoming the constraint of perishability.

Smart packaging solutions Develop packaging with built-in freshness indicators. These indicators change colour as the produce starts to deteriorate, alerting consumers about the remaining shelf life.

Produce sharing platforms

Create platforms where neighbours or community members can share excess produce. Users can post what they have available and what they need, fostering a sense of community Andermatt Madumbi - Fruit and Vegensuring Quarter Page.pdf 1 2023/10/31 while that produce11:29:39 doesn't go to waste.

GENERAL

Supply chain disruptions highlighted at IFPA conference The International Fresh Produce Association’s (IFPA's) Southern Africa Conference in Cape Town was a highlight on Southern Africa's fresh produce industry calendar. This year's conference also included a tradeshow, a leadership summit and a women's breakfast. MARIANA PURNELL CONTRIBUTOR

he fresh produce industry is estimated to have a global market value of $220 billion with more than 200 origins and 200 destinations. In 2021, the production of fresh produce reached 1,6 billion tons of which 50% was consumed locally while 50% was destined for international trade. The industry operates with high fragmentation, including a range of small, medium, and large-scale producers. This results in a complex domestic and global supply chain. Robert Guenther, Chief Public Policy Officer of IFP, discussed the initiatives of the global produce coalition and outlined how Table 1: Fresh produce industry role players have had to adapt to challenging conditions as enormous increases lead to supply chain strain. Supply chain

Shipping container

Increase in cost %

150 - 400

global supply chain disruptions are being addressed. The coalition brings together fresh produce associations from around the world, with a joint vision of creating a resilient global supply chain for fruits and vegetables. Their mission is to voice solutions to address disruptions and promote best practices. The highly perishable nature of fresh produce makes it particularly vulnerable. Guenther emphasised that despite COVID creating havoc worldwide, the fresh produce industry remained resilient. But is this the new normal? Current global supply chain challenges persist, especially due to increased costs for all parts of the sector (Table 1). Apart from the rising prices mentioned above, crop protection tools, packaging materials and materials for building

Table 2: A global perspective of the top expenses (expressed in percentage) identified by the Global Coalition of Fresh Produce Survey of industry members.

Fertilizer

Packaging

Machinery & equipment

Construction

Crop protection

Storage

Fuel/gas

Seeds

Plant material

Airfreight

Wood pallets

100

Shipping

Land/Building

Audits

Truck transportation

Electricity

Water

Utilities

100

Pallets

Labour

Fertilizer

24 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

ALGEMEEN

Robert Guenther, Chief Public Policy Officer of the International Fresh Produce Association.

greenhouses also skyrocketed. The conflict in the Ukraine has destabilised the market by disrupting the flows and thus the availability of fertilizer. Labour shortages that existed before COVID were worsened and are now spread across the entire supply chain. Driver shortages and logistical challenges are in short supply and increasingly expensive, while congestion at ports and delays wreak havoc for the industry. Worldwide rising energy costs are also adding to the impact of food inflation and making food choices difficult for the cash-strapped consumer. Guenther revealed the preliminary results of a global coalition of fresh produce survey of industry members into costs and prices (Table 2). While most role players on the supply side of the fresh produce industry were able to increase their prices, 57% of the global industry is selling at a loss or breakeven and 80% are delaying or forgoing investments in their businesses. Guenther outlined some exciting plans for 2023/24 to make fruits and vegetables even more appealing and accessible. The global coalition is on a mission to make fruits and vegetables more affordable globally by proposing a zero-VAT strategy and building on the perception of fruits and vegetables as a “strategic” or “essential good” boosting its value in the eyes of consumers. To make this happen, they are planning to step up public promotional investment and information campaigns and make more fruits and vegetables available through school feeding programs. The coalition also wants to create better job opportunities in the fresh produce and transportation industries. They intend to promote the creation of safe and better-paying jobs in the fresh produce industry and in transportation with the goal of encouraging young people to pursue careers in these fields. To address all the constraints in the market, they want to ensure that fresh fruits and veggies get top priority when it comes to transportation. The goal is to create stabilisation mechanisms to improve the accessibility of fresh produce. According to Guenther, they are planning to initiate dialogue to help fresh produce operators shoulder the burden of increased energy bills and introduce transport resources for fruit and vegetable growers and exporters offsetting increased expenses. They will also work to harmonise and the mutual recognition of sanitary, phytosanitary, and other market entry requirements and facilitate greater access to key export markets. The sustainability footprint of fruit and vegetables will be promoted as a solution in the climate change debate. All in all, it sounds like the Global Coalition of Fresh Produce has some fantastic plans to make our favourite foods even better for everyone!

VEGETABLES & FRUIT | NOV • DES 2023

Utilise the potential of the agricultural market

Use the specialists PUBLISHERS OF: Wheat Focus / Koringfokus: Specialist magazine for small grains Vegetables & Fruit / Groente & Vrugte: Explore markets in fresh produce Subtrop Journal: Journal for avocado, mango and litchi growers Research journals: SA Avocado Growers’ Association (SAAGA) SA Litchi Growers’ Association (SALGA)

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GENERAL

Management of irrigation in

ONION PRODUCTION According to the Food and Agriculture Organization (FAO), there are inadequate natural water resources in South Africa to meet the demands of the region. Approximately 60% of available water is being used for agriculture. With a higher rate of urbanisation and a rising population, the pressure for effective water management is increasing. Water resources should be used sustainably whilst promoting economic growth and food security. Onion producers need to take note of the importance of implementing efficient water management practices, by applying irrigation at crucial growth stages during onion production.

or commercial onion production in South Africa, there are various irrigation methods that can be used, including center pivots, sprinkler, drip and furrow irrigation. The choice of irrigation method will depend on the quality and abundance of water supply, size of the field, climate, type of equipment and overall cost of each system. Many hectares of onions are produced under center pivot systems in Limpopo, North West, Northern Cape and Western Cape, which includes the biggest onion production regions in South Africa.

Irrigation and water use efficiency Water application efficiency (AE) is a measurement of how effective the irrigation system is in delivering plant-available water to the root zone. It is expressed as the percentage of total volume of water delivered to meet crop evapotranspiration Table 1: Potential Application Efficiency (AE) in well-managed irrigation systems.

Irrigations System

Potential AE (%)

Pivot Irrigation system

Center Pivot Linear Move

85-95 85-95

Micro-irrigation system

Surface Drip Sub-surface Drip Micro spray

85-95 90-95 85-90

Surface-irrigation system Furrow (conventional

45-65

(ET) needs. Mechanisms of water loss include surface run-off, percolation out of root zone, evapotranspiration from soil, leaf canopy and wind drift. These factors, as well as leaks in irrigation pipes, lower the AE of an irrigation system which consequently lowers the effectiveness of water applied (Table 1). Well-designed pivot irrigation systems can have an AE of 85-95%, making them more efficient than sprinkler irrigation. Evaporation from the leaf canopy, soil surface, droplets in the air, as well as wind drift, are the most common factors of water loss in pivot systems. To minimise this, consider using a low-pressure sprinkler adaptation that produces larger droplet sizes that can reduce water losses due to wind drift and evapotranspiration from the air. Water runoff can be an issue with this system if application rates are higher than soil intake rates. This can also be managed by producing onions in ridges to minimise losses due to runoff. Drip irrigation systems are very effective since the application of water is close to the root zone. This means less water is lost due to evapotranspiration from the soil. Ensure that the flow rate of dripper lines is at an appropriate rate for the type of soil in the onion field. On heavy soils, lower flow rates and wider drip-line spacing should be used since water tends to move more horizontally in the soil profile. On lighter soils, faster flow rates and closer drip-line spacing should be used for more uniform wetting of root zones across the bed. Water quality is extremely important while using this system since driplines can become clogged and should be managed accordingly.

Water usage in onion

Seasonal water use of onion.

Onions have a shallow root system with most roots in the top 18 - 30 cm of soil. Due to the sparsely branched root system, onions are sensitive to water stress. It is essential to maintain soil moisture in the upper layer for good bulb development. Onions are also sensitive to water logging during phases of heavy rains, flooding the top layer of soil. Rainfall should be a consideration when planning sowing dates in specific production areas. For optimal growth during bulb development and maturity, humidity between 65 and 75% and 500 - 600 mm of well-distributed rainfall is required.

26 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

ALGEMEEN Irrigation is an important factor for stand establishment in onions, especially in the Northern production region of South Africa where temperatures are very high during planting. The topsoil should not be allowed to dry out and frequent, lighter applications are advised since onion seedlings do not use much water. The water need of onion plants increases as the plants grow, reaching maximum water use during the bulb deve lopment stage (Table 2). The water need declines as the plant reaches maturity and irrigation is stopped to allow field curing of the onion bulbs. Production of optimal yield and quality is reliant on soil moisture levels in the topsoil. Onions have a relative water demand, thus plant-available water should not drop below 75% as water uptake declines below that level. Adequate soil moisture promotes bulb development over root growth leading to well-developed bulbs. Water stress or irregular irrigation can lead to split bulbs which reduces shelf-life and marketable yields. Deficit irrigation also leads to less vigorous leaf growth, soft bulbs with reduced storage potential, reduced bulb fresh weight, smaller bulb size and overall lower quality bulbs.

Improving application efficiency In pivot irrigation, the application efficiency can often be reduced as application frequency increases. During every application, a percentage of applied water will evaporate. The rate of evaporation is influenced by climate and the surface area of the droplets. Loss through evaporation can be reduced by lowering the frequency of irrigation and utilising the most crucial stages in onion development. Determining the soil moisture estimates is important for ir-

rigation scheduling. Overall efficiency of irrigation can be improved by determining the soil moisture estimates, to avoid over-watering or water stress. Irrigation flow meters are also a helpful tool for monitoring the total volume of water pumped. This data can assist with irrigation scheduling, detection of problems and monitoring system performance and efficiency so that necessary adjustments can be made. Conservation tillage practices such as no-till and strip tillage improve the water-holding capacity, soil moisture retention, water infiltration rates and a reduction in run-off water. This leads to greater available soil moisture and a reduction in possible periods where water stress may have been a factor. Routine maintenance is also important to periodically inspect and maintain irrigation systems for best performance. The uniformity of water application has an influence on onion bulb development and growth and should be avoided at all costs. Encouraging better irrigation performance by using application efficiency rates is one of the first factors to deal with the rising concern of water scarcity. Implementation of effective irrigation systems, paired with knowledge of crucial times in onion development where more or less water is needed, will be beneficial for both onion producers and the community. DISCLAIMER: This information is based on observations and/or information from other sources. As crop performance depends on the interaction between the genetic potential of the seed, its physiological characteristics, and the environment, including management, no warranty is given express or implied, for the performance of crops relative to the information given nor do Sakata accept any liability for any loss, direct or consequential, that may arise from whatsoever cause. Please read the Sakata Seed Southern Africa (Pty) Ltd Conditions of Sale before ordering seed.

GENERAL

The effect of pre-harvest application of Crop4Life on fungal decay in Cape gooseberries (Physalis peruviana) Cape gooseberries (Physalis peruviana) are a minor crop grown in South Africa. Generally, the post-harvest longevity of fruit is poor, particularly when the calyx is detached, and berries are highly prone to decay. However, very few formal studies have been done on post-harvest diseases of gooseberry in South Africa and around the world.

ecent post-harvest decay studies were done at the department of agronomy at Stellenbosch University, which confirmed Botrytis cinerea, Rhizopus stolonifer and Penicillium expansum as causal organisms of post-harvest decay in Cape gooseberries. In 2022, a small plot trial was planted in a tunnel at the Stellenbosch University to evaluate the effect of the pre-harvest application of the biostimulant Crop4Life (C4L) on post-harvest decay of gooseberries. The product was applied to plants (growing in an 8 x 1 m plot) at flowering and 4 weeks later at a dosage of 50 ml/100 L as a drench application. Plants growing in a separate plot were left untreated to serve as the untreated control. Once berries were ready for harvest, they were harvested, sterilised, artificially injured with a needle-like device and inoculated with spore suspensions of the three fungi respectively. Post-harvest decay was evident in all inoculated berries, and there were no significant differences in the extent of decay in berries. Interestingly, the sporulation of all three fungi was significantly inhibited by the pre-harvest application of C4L. The sporulation of fungi on decaying fruit contributes to secondary infection of fruit in the proximity of the diseased fruit. This finding could have application in reducing the secondary infection of berries in storage, since it holds to reason that there will be a lower amount of fungal inoculum available to infect neighbouring fruit.

Further studies with the product, with more pre-harvest applications, should be pursued to verify the information and further explore the product's effect on post-harvest decay of berries (also berries other than Cape gooseberry). Other observations, such as bigger fruit size, higher flesh firmness and slower moisture loss in the treated fruit also justify further studies on this organic, non-toxic product, which has no withholding period. The product has huge potential to support Cape gooseberry production and potentially the production of other berries and further studies are recommended.

More about the Cape gooseberry The Cape gooseberry is a woody perennial shrub in the Solanaceae family that can grow up to two metres if pruned and guided (CABI, 2022). It is native to South America and is grown widely in many countries. Plants thrive in tropical and subtropical climates and may be planted as ornamentals, for medicinal purposes and fresh consumption of the fruit. The round orange-yellow berries, 1-2 cm in diameter, are enclosed in a straw-coloured husk formed from the calyx (CABI, 2022). This crop was first grown commercially in the 1980s and is now available to consumers in many parts of the world as fresh fruit but also as processed products like jam and juice (Olivares-Tenorio, 2017).

28 VEGETABLES & FRUIT | NOVEMBER • DECEMBER 2023

ALGEMEEN

Figure 1: Gooseberries that did not receive an application of C4L were visibly smaller (on the left side of the photo) than gooseberries that received two applications of C4L during the growing season (on the right side of the photo).

Figure 2: Gooseberries, without the husk, that did not receive an application of C4L were visibly smaller (on the left side of the photo) than gooseberries that received two applications of C4L during the growing season (on the right side of the photo).

Table 1: The sporulation of fungi in untreated berries was significantly greater than the sporulation of fungi in the control treatment.

Fungal pathogen

Untreated berries

Berries treated with C4L

Sporulation index (0-3)

Botrytis cinerea

2.6a

1.7b

Penicillium expansum

2.4a

1.9b

Rhizopus stolonifer

2.8a

1.8b

Values followed by different alphabetical letters differ significantly p<0.05

Yields, depending on the age of the plants, range from 5-15 tonnes per hectare (CABI, 2022). Fruit quality is affected by post-harvest decay which diminished the value of fruit in local and export markets (Balaguera-López, et al., 2015; Olivares-Tenorio, 2017). Fungal decay may cause a loss of up to 30% of the yield after harvest (Trinchero et al., 1999). The climacteric ripening of gooseberry allows for the fruit to be exported, since fruit continues to ripen after harvest (Panayotov and Popova, 2015). This also means that the quality of the fruit declines after picking, and interestingly more so if the calyx is detached (Olivares-Tenorio, 2017). When the calyx is removed from the Cape gooseberries, the fruits have higher respiration rates, generating higher levels of ethylene which accelerates decay (Olivares-Tenorio, 2017). If the calyx is attached, the incidence of decay is lower, and the harvested fruit may be stored for as long as four months at circa 2 °C (CABI, 2022).

More about the biostimulant Crop4Life is a plant-based organic biostimulant registered for use on 48 crops in South Africa. The commercial use of the product follows solid scientific research (>500 trials done over >10 years). In the most in-depth investigation of the product to date, Loubser evaluated the effect of C4L on Arabidopsis thaliana (a plant from the mustard family) and tomato (Solanum lycopersicum). On tomato, with C4L applied as a foliar spray, treated plants had a significant increase in root and shoot biomass. For tomato, 33 308 transcripts were analysed and about 18% of the transcripts were expressed significantly differently from the untreated control plants. Although C4L improves the yield and quality of crops and elicits abiotic stress tolerance, no information is available on the product's potential impact on fruit's post-harvest decay. This study aimed to determine if the pre-harvest application of

the biostimulant C4L has an impact on the post-harvest decay of gooseberries.

Materials and methods Inoculation of gooseberries with fungal cultures Nine, freshly harvested gooseberries per treatment (viz treated with C4L {x2} or untreated) of the cultivar ‘Super-Size’ were packed onto sterile paper trays. After packing it out on the trays, the berries were surface sterilised with a 70% ethanol solution applied with a spray bottle. The berries were allowed to air dry before being wounded once with a needle-like device (1 mm x 1 mm). A 10 μl aliquot of spore suspension was pipetted onto the single wound with sterile techniques (respectively for the three fungi). Control fruit was wounded and inoculated with a 10 μl droplet of unamended, sterilised water. The paper pulp tray was covered with sterile cling film (to maintain high relative humidity and prevent cross-contamination from the environment). Trays were randomised and subsequently stored in an incubator at 23 °C (day/night) for 6 days.

Results When decay between berries treated with C4L was compared to decay in berries that were not treated with C4L, there were no significant differences between the decay induced by the three different pathogens. • When fungal sporulation in C4L-treated berries was compared to that of untreated control berries, there were significant differences in the sporulation of all three fungi. • In all instances, fungal sporulation in treated fruit was significantly less than fungal sporulation in untreated fruit. • Fungal sporulation of decaying fruit contribute to the secondary spread of decay while fruit are in transit to export markets, or on shelves at local retailers. The reduction of sporulation of the decay-causing fungi might contribute to

TO PAGE 30

VEGETABLES & FRUIT | NOVEMBER • DESEMBER 2023

GENERAL

The effect of pre-harvest application of Crop4Life on fungal decay in Cape gooseberries |

FROM PAGE 29

Figure 3: Gooseberries to indicate differences in size were randomly selected from the harvest bag of about 300 gooseberries.

a lower rate of spread of the decay while fruit is in storage. • Since the control of Botrytis cinerea specifically is becoming all the more difficult to manage, this effect of the product may contribute to an integrated disease management strategy to lower decay experienced in Cape gooseberries.

The suppression of fungal sporulation is encouraging, since the product is fully organic, and it does not have any withholding periods. Further development of the product may prove it useful for integrated disease management of post-harvest decay in Cape gooseberry and perhaps also for other berries that spend prolonged periods in storage.

Additional observations Berry size • The study aimed to determine the effect of two applications of C4L on the fungal decay of Cape gooseberry. Thus, the size of the berries was not measured as a parameter, but a clear difference in the size of the harvested berries was visible (Figure 1). When gooseberries were de-husked the difference in size was still apparent (Figure 2). • For visualisation of size differences, berries were randomly chosen from the two harvest bags, one for the non-treated berries and one for the treated berries containing about 300 harvested berries each (Figure 3). Berry firmness • Berries that received C4L were firmer than those that did not receive C4L. Berry moisture loss • Remaining harvested berries were stored in sterilised paper trays for two weeks at ambient temperatures (day/night) for observational purposes. • Berries that received C4L were less shrivelled than those that did not receive the product.

Discussion and recommendations This is the first study on the effect of C4L on fungal infection and decay in Cape gooseberry. The product was applied to mature plants at two dosages, but under label recommendations, the plants may receive up to four more applications of the product: two in the seedling stage after planting, and two additional applications while plants are actively growing. It is thus recommended that the research should be repeated with a greater number of C4L applications, with the first application being at the seedling stage – perhaps the product will prove to have more benefits if applied for a longer duration (as per the label instructions for crops similar to gooseberry).

References

BALAGUERA-LÓPEZ, H.E., MARTÍNEZ, C.A. AND HERRERA, A. 2015.M Refrigeration affects the postharvest behaviour of 1-methylcyclo-Y propene-treated Cape gooseberry (Physalis peruviana L.) fruits with CM the calyx. Agronomía Colombiana, 33(3), pp.356-364. CABI, 2022. CABI Compendium. Wallingford, UK: CAB International.MY Physalis peruviana (Cape Gooseberry) | CABI Compendium (cabi-CY digitallibrary.org) GREEN, M. R. AND SAMBROOK, J. 2019. Estimation of Cell Num-CMY ber by Hemocytometry Counting. Cold Spring Harbor Proto-K cols, 2019(11), pdb. prot097980. https://doi.org/10.1101/PDB. PROT097980 LOUBSER, J. 2020. Analysis of the molecular and physiological effects following treatment with BC204 in Arabidopsis thaliana and Solanum lycopersicum. PhD Dissertation, University of Stellenbosch. OLIVARES-TENORIO, M.L 2017. Exploring the potential of an Andean fruit: An interdisciplinary study on the Cape gooseberry (Physalis peruviana L.) value chain, PhD thesis, Wageningen University and Research, Wageningen, NL. ISBN: 978-94-6257-985-9 DOI http:// dx.doi.org/10.18174/393622 PANAYOTOV, N. AND POPOVA, A. 2015. Influence of the different rate of nitrogen on the possibilities for post-harvest ripening of the Cape gooseberry (Physalis peruviana L.) fruits. Scientific Papers. Ser. B, Horticulture, 49, pp.245-250. RAMÍREZ, F. AND DAVENPORT, T.L. 2021. Uchuva (Physalis peruviana L.) reproductive biology. Springer International Publishing. ROSNER, B., GLYNN, R.J. AND LEE, M.L.T. 2006. The Wilcoxon signed rank test for paired comparisons of clustered data. Biometrics, 62(1), pp.185-192. TRINCHERO, G.D., SOZZI, G.O., CERRI, A.M., VILELLA, F. AND FRASCHINA, A.A., 1999. Ripening-related changes in ethylene production, respiration rate and cell-wall enzyme activity in goldenberry (Physalis peruviana L.), a solanaceous species. Postharvest Biology and Technology, 16(2), pp.139-145.

This research article was adapted by editorial staff of Vegetables & Fruit magazine for editorial purposes. Editor.

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