EVALUATION OF NATURAL AND ENGINEERED RESISTANCE MECHANISMS IN SOLANUM-TUBEROSUM FOR RESISTANCE TO PHTHORIMAEA-OPERCULELLA (LEPIDOPTERA, GELECHIIDAE)

Potato tuber moth, Phthorimaea oprrculella Zeller, is a highly destruc tive pest of cultivated potato, Solanum tuberosum L., and is responsib le for damage to both leaf and tuber tissues. Host plant resistance is a central component to developing ten integrated pest management prog ram to control potato tuber moth. This research tested the efficacy of a codon-modified CryV-Bacillus thuringiensis (CryV-Bt) gene constitut ively expressed in potato and the combined effect of CryV-Bt expressio n with natural host plant resistance mechanisms in potato. 'Lemhi Russ et' and 2 lines with host plant resistance mechanisms, USDA8380-1 (lea f leptines) and L235-4 (glandular trichomes), along with the CryV-Bt-t ransgenic lines of each of these 3 genotypes were examined. Detached l eaf bioassays were conducted to examine control of potato tuber moth. Nontransformed Lemhi Russet and L235-4 were susceptible to potato tube r moth, while 54% potato tuber moth mortality was found when first ins tar larvae fed on USDA8380-1 leaves. High levels of expression occurre d in the CryV-Bt transgenic Lines, with up to 96% potato tuber moth mo rtality. These transgenic lines provide a germplasm base to examine co mbined insect-resistance mechanisms as a means to achieve durable host plant resistance.