Have no fear, the aphid fungus is here
Published 5:11 pm Friday, June 24, 2016
By Ty Torrance
I have scouted multiple fields this year with heavy aphid pressure causing untimely stress to cotton plants.
Aphids are a pest of cotton every year, but their presence is usually followed by a population crash caused by a fungus.
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Dr. Roberts from The University of Georgia explains it best, “Each year aphid populations build and we anxiously wait for the fungal epizootic or crash. We have very effective insecticides for controlling aphids; however, UGA research cannot demonstrate a consistent yield response when treating aphids in cotton.
“With that said there are likely fields which may need treatment for aphids in Georgia each year, but that would be a small percentage of the acreage. In the few trials where we have observed yield responses, failure to control aphids resulted in stunted plants compared with protected plots. It is a judgment call when and if to treat aphids, but I would consider the condition of the plant. If growth is being impacted across the field (like we see in the original aphid hot spots now) treatment may be warranted. Another indication would be yellowing of terminals.
“Before making an insecticide application, be sure to look for the naturally occurring fungus which will cause aphid populations to crash. The presence of gray fuzzy aphid cadavers is indicative of this fungus. Once the aphid fungus is commonly observed in a field, we anticipate the population to crash in a few days.”
A small amount of fungus was found in Decatur County this week; we look forward to seeing the population crash in the near future.