Peanut seed treatment crisis

All commercial peanut seed is tested by the Georgia Department of Agriculture Seed Laboratory in Tifton to ensure that certain quality standards are met. This winter the seed lab started finding unexpectedly low germination in some seed lots, as well as visible contamination from Aspergillus flavus growing on the seed. All peanut seed are treated with fungicides to help control such issues, and the lab noticed that seed treated with Rancona had less Aspergillus contamination, and in some cases remarkably higher germinations, than did seed treated with Dynasty. UGA plant pathologists collected different seed lots and plated them out to evaluate the mycoflora and try to determine the cause of the problem. It was evident that majority of the seed lots were heavily contaminated with A. flavus, and that seed treated with Rancona had considerably less colonization from this pathogen. In addition, 70 of the isolates collected were evaluated in the UGA Molecular Diagnostics Lab in Tifton, and 65 percent were found to be highly resistant to azoxystrobin, one of the main ingredients in Dynasty. Another 20 percent were partially resistant. UGA findings were disseminated to the seed industry, and with the rapid approach of planting season they quickly started transitioning to Rancona. This was a huge change for the industry as Dynasty has been the dominant product for many years. The manufacturer of Rancona, UPL, had to run extra shifts in their Valdosta plant to try and meet the sudden demand. They could not produce enough to completely replace Dynasty in the short time prior to planting, but much of the seed for the 2020 peanut crop in Georgia was treated with Rancona.

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