Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/27/2010
Publication Date: 2/8/2010
Citation: Dowd, P.F. 2010. Mycotoxin management studies by USDA-ARS, NCAUR in 2009 [abstract]. Abstract 1.
Technical Abstract: Studies again included several popcorn fields in 2009 in order to continue gathering data for modification of the previously developed management strategies for mycotoxins in field corn (including the mycotoxin predictive computer program). Without an attempt for optimization, the field corn model gave overall predictions that were correlated 0.65 with actual values for fumonisin in popcorn over 2005-2008 suggesting modification of the model for popcorn should not be too difficult. Examination of popcorn data from 2005-2008 indicated within a year differences in fumonisin levels were primarily associated with insect damage levels. DON levels in 2008 were relatively independent of insect damage. Prior crops of rye appeared to increase levels of DON in some sites. Weather conditions were cooler and wetter for growing corn in 2009, and excess rainfall may have contributed to greater levels than normal of Fusarium-molded corn where insect damage occurred in ears, as well as areas where no insect damage occurred. Damage by caterpillars was relatively low overall. Earlier planted corn escaped most European corn borer damage in ears, as has been noted in the past. Western bean cut worm moths were found in traps at all locations, but few were seen as caterpillars in milk stage ears. However, damage characteristic of these caterpillars was found in harvest stage ears at several locations. Some fields also had significant stink bug damage, and sap beetle damage (in hybrids where husks did not cover tips well). No obvious visible Aspergillus flavus (the mold that makes aflatoxin) was found. Most insect damaged kernels were visibly molded by Fusarium. Mycotoxin levels of samples have not been received yet. As in 2008, a higher percentage of ears than normal were seen with "late" mold that occurred after ear fill, primarily at the base of the ear. Based on comparisons of weather data over the past several years, this appears to be due to higher than normal rainfall during dry down and is worse in ears with open husks. Upgrading the predictive computer program on the website is continuing. 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.