Effects of Transgenic Petunia Expressing Bacillus thuringiensis Toxin on Selected Lepidopteran Pests
Abstract:Toxicity of 11 transgenic petunia lines expressing the CryIA (c) insecticidal crystal protein of Bacillus thuringiensis subsp . kurstaki was investigated using lepidopteran neonates Spodoptera exigua, Trichoplusia ni and Manduca sexta. Mortality of S. exigua, T. ni and M. sexta varied within and among transgenic petunia lines . Bioassay results demonstrated that levels of CryIA (c) expression obtained in 7 out of the 11 transgenic petunia lines produced at least 50% mortality in S. exigua and T. ni, and all 11 transgenic lines produced more than 80% mortality in M. sexta. Demographic analysis of the biological impact of transgenic petunia on S. exigua revealed that sub - lethal feeding on transgenic petunia significantly reduced larval weight and prolonged larval and pupal development times . Continuous feeding on transgenic petunia significantly reduced lifetime fecundity , egg hatch and longevity in female and male moths . Compared with insects fed continuously on non - transgenic petunia , lifetime fecundity and net reproductive rate were reduced by 58 and 84% in insects fed continuously on transgenic petunia respectively . Mean generation time was 8 days longer for insects fed continuously on transgenic petunia than for insects fed on non - transgenic petunia . Ovipositional attractiveness of transgenic petunia to S. exigua with respect to non - transgenic tomato or lettuce plants was similar , suggesting that petunia / tomato and petunia / lettuce may not be effective trap - cropping combinations . The potential and implications of using transgenic petunia as trap plants interplanted with crop plants for management of lepidopteran pests in the field are discussed .
Document Type: Research Article
Publication date: September 1, 1997