Paper presented at the 52nd CFCS Annual Meeting, Guadeloupe, July 10-16, 2016
MANAGING WHITEFLY (BEMISIA TABACI) ON GREENHOUSE TOMATO WITH BIOPESTICIDES Michelle Samuel-Foo1 , Hugh A. Smith1 and Babu Srinivasan2 1
University of Florida and 2University of Georgia
Keywords : Sweetpotato Whitefly, Bemisia tabaci,Greenhouse Tomato, Biopesticides Abstract The US Environmental Protection Agency (EPA) defines Biopesticides as certain types of pesticides derived from natural materials such as animals, plants, bacteria, and certain minerals. There are many benefits associated with biopesticides: they are inherently less toxic when compared to conventional chemistries; are narrow spectrum in efficacy, generally affecting only the target pest and closely related organisms; are typically at low risk for resistance and are generally compatible with pollinators and biocontrol. In 2014, the IR-4 Program, which is the entity that helps procure registration of sustainable pest management tools for specialty crop growers, via its Biopesticides and Organic Support Program, identified whitefly control on greenhouse (GH) tomato as a priority need during a stakeholder led national workshop. In 2015 two studies were conducted in Florida and Georgia whose objectives were to evaluate a selected group of biopesticides for efficacy and phytotoxicity on GH tomatoes for control of whiteflies. This presentation will highlight the results of these studies. Materials and methods The efficacy of nine biological pesticides for control of SPW on greenhouse-grown tomato was compared to Sivanto and a non-treated check at the locations in Georgia and Florida. Each treatment was replicated 4 times and each replicate consisited of 4-5 tomato plants enclosed in mesh covered cages. All cages were arranged on greenhouse benches in a RCB design. The plants were hand watered and liquid fertilized as needed. The treatments were as follows: (1) Non-treated control, (2) Agri-Colle at 3 liters per acre, (3) EPL-1001 at 135 oz per acre, (4) Botanigard ES at 1 qt per acre, (5) PFR 97 at 28 oz per acre, (6) MBI 203 at 12 qt per acre, (7) MBI 206 at 8 qt per acre, (8) Requiem Prime at 3 qt per acre, (9) Mycotrol O at 1 qt per acre, (10) M-Pede at 2% v:v, and (11) Sivanto at 14 oz per acre. Plants were infested from laboratory SPW colonies at both locations. Treatments were applied to the plants outside their cages using a hand-held sprayer with a spray wand outfitted with a nozzle containing a 45° core and a no. 4 disc. The sprayer was pressurized by CO2 to 40 psi and calibrated to wet the leaf surfaces thoroughly without excessive runoff. Sampling was performed over a period of 3-4 weeks and consisted of ten leaflets per plot, selected randomly from the middle one third strata of the plants. Samples were transported to the laboratory where SPW were counted on the lower leaf surfaces with the aid of a stereo microscope. Main results In the FL trial, all treatments resulted in lower total nymphal densities than the UTC, however treatments of Sivanto and PFR-97 resulted in the lowest densities.In the GA trial, a number of biopesticides such as Agri-colle, EPL-1001, Requiem, Mycotrol, and M-pede were comparable with the conventional standard Sivanto in reducing immature populations. The effects of biopesticides on eggcounts were not all that clear and no significant differences from the non-treated control were obvious. Conclusion This study suggests that a handful of biopesticides could be useful for whitefly management under certain conditions, particularly when virus management is not a concern.Several applications might also be necessary to notice substantial effects on whitefly populations.
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