Comparison of Frequency of Kdr-type Resistance to Cyhalothrin in Cotton Bollworm from Xinjiang and North China

The frequencies of alleles for kdr type resistance to cyhalothrin in field populations of Helicoverpa armigera collected from Xinjiang and North China were evaluated by single-pair mating and hot-probe method. It was found that there was no individual of kdr-type resistance, including heterozygote of resistant gene, in the population of Xinjiang.The frequencies of alleles for kdr-type resistance to cyhalothrin were estimated as 20.83% and 11.11% in JF1 and JF2population, respectively. The results indicated that Xinjiang population was still suscepitible, however, kdr-type resistance had developed at high level in Jizhou population. The results also showed that most of resistant individuals were heterozygotes, but a few were homozygous resistant in JF1 population.