1997 年 1997 巻 44 号 p. 113-115
A rapid sensitivity test using a toothpick was employed to detect resistant strains to benzimidazole, dicarboximide and diethofencarb in B. cinerea on tomato in Futtsu, Chiba Pref., Japan. The test constituted of the following: picking up of conidia from one single lesion of a diseased fruit of tomato with a toothpick, inoculating the conidia on to a fungicide amended selective medium for B. cinerea and observation of colony formation on the medium to determine fungicide sensitivity of the isolate. Of all isolates derived from 130 lesions, sensitivity of eighty five isolates (65.4%) could be determined. The most frequent phenotype of sensitivity was benzimidazole-resistant, dicarboximide-resistant and diethofencarb-sensitive (RRS) and its frequency, was 60.0% of all solates. On the other hand, the frequency of the phenotype resistant to all these fungicide (RRR) was the least, 1.2%. No clear correlation was observed between fungicide sensitivity of isolates and fungicide use on the field where the isolates were collected.