A whole leaf bioassay to determine the efficacy of two Bollgard II® cotton varieties against cluster caterpillar, Spodoptera litura (Lepidoptera: Noctuidae).
Helen SpaffordA, Geoff StricklandB and Justin FairheadA
A School of Animal Biology (M085), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
B Cotton Catchment Communities CRC, Department of Agriculture and Food, Western Australia, 3 Baron-Hay Court, South Perth, Western Australia 6151, Australia.
A whole leaf bioassay was performed to determine the survivorship of neonate larvae of the lepidopteran pest Spodoptera litura (Lepidoptera: Noctuidae), the cluster caterpillar, feeding on old and young leaves of Bollgard II® cotton varieties. Larval survivorship was reduced on the Bollgard II varieties compared to a non-transgenic control but only when larvae fed upon the old leaves. Neonates that fed on young leaves of Bollgard II varieties showed no significant variation to the non-transgenic control in relative mortality or weight gain. This study indicated that there may be differential expression of the Bacillus thuringiensis Berliner toxin in Bollgard II cotton leaves and, as a consequence, Bollgard II varieties might not be able to adequately control S. litura in the field.
Keywords: transgenic cotton, cluster caterpillar, Spodoptera litura, Bollgard II, Bollgard II Roundup Ready®, integrated pest management.
Plant Protection Quarterly (2007) 22 (3) 92-95.