TRANSGENIC POTATO EXPRESSING THE BACILLUS-THURINGIENSIS CRYIA(C) GENE EFFECTS ON THE SURVIVAL AND FOOD-CONSUMPTION OF PHTHORIMEA-OPERCULELLA (LEPIDOPTERA, GELECHIIDAE) AND OSTRINIA-NUBILALIS (LEPIDOPTERA, NOCHUIDAE)

Second generation transgenic potatoes were grown from tubers of transgenic plants expressing the Bacillus thuringiensis CryIA(c) gene. Leaf disks from transgenic and untransformed potato plants were tested against the tubermoth Phthotimea operculella (Zeller), a major pest of potato, and European com borer, Ostrinia nubilalis (Hubner), which can use potato as an alternative host. Ten percentage of mortality of first-instar P. operculella was observed after 48 h of feeding on leaf disks from transgenic plants. Bioassays also showed that second-instar P. operrulella is slightly less capable of surviving on leaf disks from transgenic plants than on untransformed plants after 240 h of feeding. The amount of feeding of P. operculella larvae was also less, as indicated by lighter weight of the dried frass. Bioassay showed that second-instar European com borer is less capable of surviving on leaf disks from transgenic plants than those from untransformed plants. Preference tests showed that leaf disks from transgenic plants were less preferred than those from untransformed plants by third-instar com borer after 24 h of exposure. Prolonged exposure showed that leaf disks from transgenic and untransformed plants were equally preferred by com borer larvae. These transgenic plants can be used together with untransformed plants or transgenic plants (or both) expressing high quantity of B. thuringiensis insecticidal protein to devise insect resistance management strategies.