The Study On Sensitivity And Resistant Risk Assessment Of Botrytis Cinerea To SYP-Z048

Gray Mould, one of major fungal diseases on vegetable and fruit crops, can cause severe losses of vegetables. The control of gray mould relies on application of chemical synthesized fungicides. But the contradict between chemical control and occurrence of the fungal resistance to the fungicides is standing out increasingly. SYP-Z048, a novel fungicide, which was developed by Chemical Institute of Shenyang , has special mode of action to Botrytis cinerea. It has never been used in Hebei province. In the view of widespreading occurrence of resistance to the most of systemic fungicides in Botrytis cinerea , the study of resistance of Botrytis cinerea to novel fungicide is in critical request .The results were shown as follows about cross-resistance between other fungicides and SYP-Z048 ,baseline-sensitivity to SYP-Z048, risk resistance assessment to SYP-Z048 in the lab,the physiological and biochemical parameters comparison of resistant mutants and parental isolates to SYP-Z048,and the synergistic interaction of mixing combinations between SYP-Z048 and pyrimethanil.1. Sensitivity to pyrimethanil, procymidone, carbendazim, and difenoconazole was determined of 11 SYP-Z048-sensitive strains and 3 SYP-Z048-resistant strains. Correlation coefficient is 0.0069,0.0006,0.0007 and 0.0018 respectively in linear regression analysis between EC50 values of SYP-Z048 and pyrimethanil, procymidone, carbendazim, and difenoconazole, which indicated that the correlation between EC50 values of SYP-Z048 and the other four fungicides is poor; there was no positively coorelaled cross-resistance between SYP-Z048 and the four fungicides.2.The baseline-sensitivity of Botrytis cinerea to SYP-Z048 was established. The sensitivity to SYP-Z048 of a total of 102 single-spore isolates, accquired by single-spore from the leaves and fruits of tomato and cucumber infected by Botrytis cinerea collected from greenhouse and plastic tunnels in Baoding, Langfang, Chengde and Hengshui of Hebei Province where SYP-Z048 was never used, was determined by mycelial growth rate inhibition test. The frequnency of EC50 values distributed as a unimodal curve, ranging from 0.0460 to 0.1991μg/mL, with a mean value of (0.1182±0.0363)μg/mL. No subpopulation resistant to SYP-Z048 appeared among these isolates, so the data could be used as baseline sensitivity of Botrytis cinerea to SYP-Z048.3. Seven SYP-Z048-resistant mutants were obtained through ultraviolet irradiation. It was found that the resistant mutants significantly decreased in the colonies diameter, mycelial weight,sporulation, sclerotial number and pathogenicity, compared with their parental single-spore isolates. And the resistance level of SYP-Z048-resistant mutants receded as the resitant mutants to SYP-Z048 was subcultured on PDA plate in absence of fungicides. Thus, a low or moderate risk of resistance to SYP-Z048- is supposed to exist in Botrytis cinerea in fields.4. Through test of conductivity of amended with plugs of SYP-Z048-resistant mutants and their parental isolates for the same time, it was found that osmosis of resistant mutants were higher than their parental isolates. Besides, SYP-Z048-resistant mutants were extremely sensitive to high concentration of glucose and NaCl agar. The resistant mechanism of Botrytis cinerea to SYP-Z048 will be refered to this results.5. The highest synergistic ratio of mixtures was found to be 1:9 in the 52 mixtures of SYP-Z048 with pyrimethanil through test of the synergistic interaction of the mixtures of SYP-Z048 with pyrimethanil against mycelial growth of Botrytis cinerea.