Effects of rate and spray volume of Bacillus thuringiensis var. kurstaki on activity against Heliothis virescens (Lepidoptera: Noctuidae) and persistence in cotton terminals
1993
Ali, A. | Young, S.Y.
Effects of rate and total spray volume on activity of Bacillus thuringiensis var. kurstaki against Heliothis virescens (F.) in cotton terminals was determined in field cotton. Higher B. thuringiensis rates caused higher initial mortality than the lower rates and maintained higher efficacy up to 3 d. Persistence did not differ significantly (P less than or equal to 0.05) among rates, and half-lives ranged from 2.4 to 3.1 d. Spray volume did not affect the activity of B. thuringiensis in cotton terminals. Half-lives for B. thuringiensis applied at a rate of 1.12 kg/ha were 3-3.1 d for 46.7, 93.4 and 140 liters/ha.
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