1. Forest Pest Management Institute, Department of Fisheries and the Environment, Sault Ste. Marie, Ontario, Canada;2. Cotton Insects Unit, Agricultural Research Service, U. S. Department of Agriculture, Brownsville, Texas 78520 USA
Abstract:
Two groups distinguishable on the basis of crystal serology have been identified within Bacillus thuringiensis var kurstaki (serotype 3 ab). The toxicities of these two groups to Trichoplusia ni and Heliothis virescens expressed as ratio also differed. It is suggested that serotype 3 ab be separated into two subgroups designated as K-1 and K-73.