Laboratory and field studies of Bacillus thuringiensis subsp. tenebrionis as a feeding deterrent to Colorado potato beetle (Coleoptera: Chrysomelidae)

Bacillus thuringiensis subsp. tenebrionis (Novodor FC) was tested for effect as a feeding deterrent to Leptinotarsa decemlineata (Say) in laboratory and field trials. In laboratory tests, eggplant leaf disks dipped in concentrations of 0%, 0.04%, 0.2%, 1.0%, 5.0%, and 10.0% (vol:vol) of Novodor FC showed no evidence of feeding deterrency to adult beetles. In two field tests, Novodor FC at rates of 0, 1.2, 2.3, 4.7, and 7 liters/ha (0, 0.5, 1.0, 2.0 and 3 qt acre, respectively) showed no evidence of repellency to fourth instars or adult Colorado potato beetles on eggplant. The lack of feeding deterrency may limit management strategies by using commercially prepared B. thuringiensis sprays in the field.