Frequency of alleles conferring resistance to a Bacillus thuringiensis toxin in a Philippine population of Scirpophaga incertulas (Lepidoptera : Pyralidae)
Js. Bentur et al., Frequency of alleles conferring resistance to a Bacillus thuringiensis toxin in a Philippine population of Scirpophaga incertulas (Lepidoptera : Pyralidae), J ECON ENT, 93(5), 2000, pp. 1515-1521
Using the F-2 screen methodology, we estimated the frequency of alleles con
ferring resistance to the CrylAb toxin of Bacillus thuringiensis Berliner i
n a Philippine population of the stem borer Scirpophaga incertulas (Walker)
. Evaluation of >450 isofemale lines for survival of F-2 larvae on crylAb p
lants did not detect the presence of an allele conferring a high level of r
esistance. The frequency of such an allele in the sampled population was co
nservatively estimated to be <3.6 X 10(-3) with 95% confidence and a detect
ion probability of 94%. However, there was evidence of the presence of alle
les conferring partial resistance to CrylAb. The frequency of alleles for p
artial resistance was estimated as 4.8 X 10(-3) with a 95% CI between 1.3 X
10(-3) and 1.04 X 10(-2) and a detection probability of 94%. Our results s
uggest that the frequency of alleles conferring resistance to CrylAb in the
population of S. incertulas sampled is not too high to preclude successful
implementation of the high dose/refuge resistance management strategy.