EVALUATION OF BT COTTONS RESISTANT TO INJURY FROM BOLLWORM (LEPIDOPTERA, NOCTUIDAE) - IMPLICATIONS FOR PEST-MANAGEMENT IN THE TEXAS SOUTHERN HIGH-PLAINS

Transgenic cotton plants, carrying a gene construction that codes for the HD-1 delta-endotoxin from Bacillus thuringiensis Berliner var. kur stakii, were evaluated for resistance to injury from the bollworm, Hel icoverpa zea (Boddie). Transgenic cotton lines containing the Bt gene suffered significantly less bollworm injury to squares and green bolls than the commercial cultivars Coker 312 and Paymaster HS26. Paymaster HS26, a cultivar well adapted to Texas High Plains growing conditions , suffered an average loss of 150 kg of lint per ha when not treated w ith insecticide to control bollworms. None of the transgenic cotton li nes required insecticide treatment to preserve yield. The present stud y indicated that well-adapted cotton varieties containing the Bt gene could play an important role in future cotton pest management in the T exas High Plains.