Mortality of Adult Corn Earworms Treated with Insecticidal Formulations in Sweet Corn in Fields and in the Laboratory

Mortality of adult Heliothis zea (Boddie) was studied by caging moths at ear and tassel height in sweet corn and applying selected insecticides with aerial and ground equipment for field evaluations and with oral feeding for laboratory evaluations. Aerial applications of Gardona® (2-chloro-1-(2,4,5-trichlorophenyl) vinyl dimethyl phosphate) and methomyl gave mortalities equivalent or superior to the standard insecticidal treatment (Niran® 6-3 (parathion (6) methyl parathion (3) + toxaphene). Emulsiliable concentrate ultra-low-volume (ULV) formulations applied with ground equipment produced similar mortalities. Low-volume dusts were less effective than other formulations. Ground applications of methomyl, Gardona WDL4 (water dispersible liquid at 4 lb/gal), carbaryl wettable powder, monocrotophos, ULV malathionmethyl parathion, and ULV malathion produced >95% mortalities. In feeding trials in the laboratory, dosages (µg/moth) of chemicals that produced 100% mortality were: methomyl 0.1; mevinphos 0.5; Gardona 5.0; Niran above 50; and DDT above 100.