ARS | Publication request: BIOASSAY OF BACILLUS THURINGIENSIS AGAINST LEPIDOPTERAN LARVAE

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: June 4, 1996
Publication Date: N/A

Technical Abstract: This book chapter reviews some of the important types of bioaasays used to asses the activity of the bacteria, Bacillus thuringiensis (Bt), against Lepidopteran larvae. Diet incorporation assays can be useful for screening new isolates of Bt or in determining the relative potency of Bt produced from different fermentations. By using a range of concentrations, the dosage necessary to kill 50% of the test population can be determined. This measure is useful for comparing different isolates and fermentation conditions. Other assays discussed include whole plant assays wherein a plant is treated with formulation after which larvae are added. This assay is a good indication of what will happen under field conditions. Leaf assays wherein disks of leaf tissue are treated, can be extremely useful to determine activity of Bt and various formulations directly on the leaf surface. Environmental factors such as sunlight or rainfall can be simulated on the leaf disks and an accurate measure of residual activity obtained.