Use of Methoxyfenozide (Intrepid) and Bifenthrin (Capture) for Management of Southwestern and European Corn Borers in Conventional Field Corn in Arkansas

Abstract

In order to conserve the gene pool of insects susceptible to Bacillus thuringiensis (Bt) protein in transgenic plants, 50% of field corn produced in Arkansas is required to be non-Bt or conventional. In conventional corn, farmers generally apply either bifenthrin (Capture) or methoxyfenozide (Intrepid) during early July to manage second generation southwestern corn borers, Diatraea grandiosella Dyar, and European corn borers, Ostrinia nubilalis (Hubner). The study reported herein sought to establish the effectiveness of the insecticide sprays on reducing corn borer feeding and increasing yield. When corn borer populations were high, as in 2003 and 2004, both Capture and Intrepid were often effective in reducing damage from tunneling larvae. In 2005, however, when corn borer population levels were lower, insecticide application failed to produce significant reductions in corn borer tunneling. Yield increases were not detected when feeding reductions were observed. Of the nine fields sampled throughout the three-year study, no significant increases in yield were detected in plots receiving insecticides when compared to non-sprayed plots. The lack of yield increase may be due to the advanced maturity of Arkansas field corn when attacked by second generation corn borers. Ears on field corn that is planted during March and early April are generally at or near dent stage (R5) by mid-July, the time of attack by second generation corn borers in Arkansas. Of the nine fields sampled, the application of the foliar insecticides significantly reduced stalk lodging in five. Thus, foliar insecticide application may offer the Arkansas field corn producer a method of reducing plant lodging.