ARS | Publication request: Mycotoxin management studies by USDA "Ag Lab" in 2011

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 9, 2012
Publication Date: February 9, 2012
Citation: Dowd, P.F. 2012. Mycotoxin management studies by USDA "Ag Lab" in 2011 [abstract]. Central Illinois Irrigated Growers Association. Paper #3.

Technical Abstract: Studies again included several popcorn fields in 2011. The research has been redirected to investigate hybrid based and environmental influences on gene expression directly and indirectly involved in resistance to mycotoxin production, so milk stage undamaged and damaged ears have been saved in the freezer for the gene expression analysis as well. Weather conditions were much wetter than normal in June, while July and August were very dry. Thus, there was potential for several different types of mycotoxins, depending on planting date and local rainfall and irrigation. Japanese beetle damaged kernels were present on the ears that did not have good husk coverage; this may have contributed to some mold and mycotoxin presence. Damage by caterpillars was extremely variable; in some cases few caterpillar damaged ears occurred. In other cases, up to 15 European corn borers were found on one ear at one location, and multiple per ear at other locations was not uncommon. Earlier planted corn escaped most European corn borer damage in ears, as has been noted in the past, but there was some damage by corn earworms. Western bean cutworm moths were found in traps at all locations, but were not common in milk stage ears. However, damage characteristic of these caterpillars was found in harvest stage ears at several locations. Stink bug and sap beetle damage was much less common than normal. Spraying for Japanese beetles may have helped reduce European corn borer damage. Some visible Aspergillus flavus (the mold that makes aflatoxin) was found, and kernels with black spots (which can be an indicator the fungus is present) were also found in some fields. Some insect damaged kernels were visibly molded by Fusarium. Only one sample assayed contained aflatoxin, which was at a very low level. Low levels of DON were found in all fields, and did not appear to be associated with insect damage. Fumonisin levels were variable, and as in the past, higher levels were associated with higher incidence of insect damage. Plans for this year are to again monitor popcorn and some field corn as in the past for insect damage, molds, and mycotoxin levels. Trap monitoring for corn earworms, European corn borers, and western bean cutworms will again occur. New competitive grant funding has permitted new experiments to be set up to evaluate insect damage to low lignin lines of sorghum, which are also being examined for bioenergy production. Greenhouse and plant growth room studies have generally indicated no significant increase in susceptibility of leaves to corn earworm or fall armyworm damage in the low lignin lines, and greatly enhanced pith resistance to these species.