theories on why we’re seeing the shift?
important to know what disease you are treating – diagnoses have become that much more imporJohn: Yes there are differences. My tant. You do a lot of disease diagthoughts on this issue are as folnostic work on turfgrass. What lows. These organisms no doubt steps do you take in diagnosing have always been around but may- disease? be not expressing themselves to the magnitude they are today. John: I like to get a look at the turfgrass stand if possible to see sympRemembering the old contact fun- toms and signs. I note the weather gicides Cadmium Chloride, Phenyl conditions and environment. Is Mercury Acetate, Calo-clor which it wet or shady? etc. I identify the is another Mercury compound and species of grass that’s being infectother heavy metals, one wouldn’t ed and try to get a little history of doubt that they controlled some of how the stand has been managed. these organisms by accident. Those At that point I can usually identify products also lasted longer. The diseases by stand symptoms and newer fungicides are more specific plant symptoms, also macroscopic in targeting certain pathogens or signs if they are there (Examples: even just one. This also would tend rust, red thread, powdery mildew). to increase fungicide resistance is- For more complicated samples I sues. Lastly, in many cases we are get sample plugs of good and dismanaging turfgrass species beyond eased turf and put it under the mitheir natural genetic abilities. croscope and see if there is enough fungus there for it to identification Angela: I couldn’t agree more! itself. If there is not enough mateWe’ve changed the circumstances rial to visualize the pathogen under of the disease triangle! Possibly the microscope, I put it in humid we’ve changed the growing envi- chamber for 12 to 24 hours and ronment such that it causes more check again under microscope. You plant stress and opportunity for need to look at the roots for patch disease development. The site-spe- diseases. Look for runner hyphae. cific fungicides make it even more Sometimes you can find fruiting
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