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Submitted to: Journal of Entomological Sciences
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/7/1997 Publication Date: N/A Citation: N/A Interpretive Summary: The twospotted spider mite can be a serious pest of soybean during periods of prolonged hot and dry weather. Studies to screen soybean germplasm for resistance to spider mites have been limited and have met with little success. Soybean lines with dense, normal, and no hairs (pubescence) were tested to determine their effects on twospotted spider mite development and dfeeding damage to the plants. The results indicated that soybean isolines with no pubescence were less preferred by spider mite adults and suffered less feeding damage than normal or dense pubescent plants. This study also demonstrated a reliable laboratory procedure for rearing the twospotted spider mite, screening soybean germplasm, and determining resistance mechanisms. The results of this study will aid soybean entomologists and breeders in the screening and development of soybean germplasm resistant to the twospotted spider mite. Technical Abstract: Studies to screen soybean germplasm for resistance to the twospotted spider mite, Tetranychus urticae Kock, have been limited and have met with little success. The objective of this study was to investigate the influence of soybean lines isogenic for pubescence type on twospotted spider mite development and feeding damage under controlled environmental conditions and a known infestation rate. Soybean lines isogenic for glabrous, normal and dense pubescence developed from the genotypes 'Davis", 'Tracy-M', and D75-10169 were used in this study. Small but significant differences in progeny and feeding damage 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 development of soybean germplasm resistant to the twospotted spider mite. 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. |
