Soybean Response to Various Levels of Podworm Damage1

Abstract

Infestations of varying numbers of Heliothis zea (Boddie) were established in 1968 and 1969 on caged soybeans to determine the number of pod worms per row-foot necessary to produce economic damage. All artificially introduced podworm infestation levels resulted in reduced yields in 1969. Based on the cost of insecticidal control applications, an introduced population level of three podworms per row-foot would justify control measures. Population levels of 1 larva per foot of row, if introduced twice, would justify control measures. Pod-damage counts were made before harvest, and each larva had partially consumed at least 6 pods.