Influence of Soybean Lines Isogenic for Pubescence Type on Twospotted Spider Mite (Acarina: Tetranychidae) Development and Feeding Damage

Soybean lines isogenic for glabrous, normal, and dense pubescence developed from the genotypes ‘Davis’, ‘Tracy-M’, and D75-10169 were used in studies of the impact of pubescence on twospotted spider mite, Tetranychus urticae Koch, development and feeding damage under controlled environmental conditions and a known infestation rate. Significant differences in progeny and feeding damage of the twospotted spider mite between genotypes were observed. There were no significant differences between isolines within genotypes for number of progeny. Glabrous isolines had significantly more adult mites leave the excised plant leaf and significantly less feeding damage than the normal or dense isolines. Results suggest that leaf pubescence, or in this case lack of, could be a potential factor in the control of the twospotted spider mite on soybean. This study also demonstrates a reliable and uniform laboratory procedure, under controlled conditions, for rearing the twospotted spider mite, screening soybean germplasm, and determining resistance mechanisms.