Effects of Pink Bollworm Larval Feeding on 'NuCOTN 33b~(R)' Cotton Bolls and Pollen and Tolerance to Cry1Ac Toxin in Artificial Diet Bioassays

摘要

Transgenic cottons (Bt), Gossypium hirsutum L., have been grown commercially in Arizona since 1996. We conducted laboratory studies from 2001 to 2005 to determine the effect of pink bollworm (PBW), Pectinophora gossypiella (Saunders), larval feeding periods on 'NuCOTN 33B~(R)' bolls on development, mortality, pupation, and tolerance to the CrylAc toxin. Initially, higher larval mortality occurred and more days were required for pupal development following four or seven day feeding periods on NuCOTN 33B~(R) bolls compared with similar feeding periods on 'Delta and Pineland (DPL) 5415' non-toxin containing bolls. Mortality and larval development time decreased as the number of larval feeding generations increased suggesting adaptation to the toxin inbolls. Some larvae of a PBW strain [BG~(R)(4)] developed by feeding for 35 of 40 generations for four days in each generation on NuCOTN 33B~(R) bolls survived to larval maturity on NuCOTN 33B~(R) pollen for 20 days or on 10 mu g/ml Cry1Ac-fortified artificial diets for 21 days. No survival of BG(4) strain larvae occurred on NuCOTN 33B~(R) bolls for more than seven days. The 10 mu g/ml CrylAc concentration in artificial diet has been determined as the discriminating dose for PBW resistance in the laboratory. No larvae of a DPL 5415 PBW control or a BG~(R)(7) strain developed to maturity when feeding on NuCOTN 33B~(R) pollen, bolls, or Cry 1 Ac-fortified diets. Moth emergence from the BG~(R)(4) strain surviving pupae from larvae on 10 mu g/ml CrylAc diet ranged from 42 to 100%, mating of emerged adults occurred and egg hatch averaged 67%, but oviposition was reduced.