Soybean genotype effects on bigeyed bug feeding on corn earworm in the laboratory

Corn earworm, Helicoverpa zea (Boddie), is a serious pest of many crops, including soybean, Glycine max (L.) Merr. This study was conducted to determine whether or not plant pubescence could be used to enhanced predator activity. The influence of plant pubescence or insect resistance of soybean on predation of corn earworm eggs by the bigeyed bug, Geocoris punctipes (Say), was investigated in the laboratory. Bigeyed bug adults were allowed to feed on corn earworm eggs that were placed on foliage of soybean genotypes isogenic for dense, normal, or no pubescence, and on genotypes susceptible or resistant to foliar feeding insects. Percent egg puncture by males was similar on all foliage types whether or not choices were offered. Females punctured significantly (P < 0.05) more eggs on normal leaflets in a no choice situation. Significant differences (P > 0.05) were not detected in percent egg puncture on soybean genotypes resistant to foliar feeding insects as compared with susceptible genotypes (|Centennial' and |Davis'). Development of soybean cultivars with reduced pubescence, which is less preferred by corn earworm for oviposition and/or foliar feeding, will probably not influence this beneficial predator, since egg predation was not adversely affected by plant pubescence or insect resistance under laboratory test conditions.