Evaluation of potato tuber moth (Lepidoptera : Gelechiidae) resistance in tubers of Bt-cry5 transgenic potato lines

The potato tuber moth, Phthorimaea operculella (Zeller), in tropical and su btropical countries, is the most destructive pest of potato, Solanum tubero sum L. The larvae attack foliage and tubers in the field and in storage. Th e purpose of this study was to evaluate the efficacy of a Bt-cry5 transgene to control the potato tuber moth in tuber tissues, Tuber bioassays using s tored (11-12 mo old) and newly harvested tubers of Bt-cry5-Lemhi Russet and Bt-cry5-Atlantic potato lines showed up to 100% mortality, of 1st instars. Mortality was lowest in the newly harvested tubers of Bt-cry5-Atlantic lin es (47.1-67.6%). Potato tuber moth mortality was 100% in the Bt-cry5-Spunta lines that were transformed with Bt-cry5 gene controlled by the CaMV 35S p romoter (pBIML5 vector) and in 2 of 3 lines transformed with Br-cry5 gene c ontrolled by the Gelvin super promoter pBMIL2 vector). The transgenic Spunt a lines expressing Bt-cry5 controlled by the patatin promoter (pBMIL2 vecto r) showed the lowest tuber moth mortality (25.6 and 31.1%). The Bt-cry5 tra nsgenic lines with high tuber expression of B. thuringiensis have value in an integrated pest management system to control potato tuber moth.