Department of Hematology, Gujarat Agricultural University, Anand Campus, Anand-388110, Gujarat, India.
To evaluate formulations of Bacillus thuringiensis Berliner var. kurstaki (B.t.k.) and neem (Azadirachtiri) for the management of cotton bollworms, field studies were conducted during 1993–94 and 1994–95 in a Latin Square Design with six treatments. B. thuringiensis var. kurstaki formulations viz. Cutlass, Delfin and Bactec treatment @ 1 kg/ha was found equally effective as the chemical insecticide treated check in protecting fruiting bodies (bud and green boll) on the cotton. However, neem was found to be less effective than B. thuringiensis var. kurstaki but better than the untreated check. Maximum yield of seed cotton was obtained with the chemical insecticide treatment followed by B.t.k, neem and untreated check treatments. AH the B.t.k formulations persisted well under the field conditions with identical half life time of 2 days. They were also found to be less toxic to predators in cotton fields compared to chemical and neem treatments.
