Co-Authors:
Navon, A., Department of Entomology, ARO The Volcani Center, Bet Dagan, 50250, Israel
Hare, J.D., Department of Entomology, University of California, Riverside, 92521, California, United States
Federici, B.A., Department of Entomology, University of California, Riverside, 92521, California, United States
Abstract:
The potential interactions among a plant-produced allelochemical, a phytophagous insect, and an endotoxin produced by Bacillus thuringiensis were investigated using purified cotton condensed tannins, the CryIA(c)δ-endotoxin from B. thuringiensis subsp. kurstaki strain HD-73, and larvae of Heliothis virescens. Purified condensed tannin from cotton fed to neonate H. virescens reduced feeding and mortality caused by insecticidal crystals of B. thuringiensis. In fifth instars, tannin reduced relative growth rate (RGR), relative consumption rate (RCR), but antagonized the effects of the crystal δ-endotoxin. Tannin did not deter feeding of fifth instars in choice tests with cellulose-ester disks. Masking tannin from interacting with the dietary ingredients of artificial diets and crystal protein by encapsulation in alginate gel suggested that tannin adversely affected feeding after ingestion.These results suggest that insect control tactics that employ δ-endotoxins in microbial insecticides and transgenic cotton plants may not be compatible when used in conjunction with plants containing high tannin concentrations. © 1993 Plenum Publishing Corporation.