ارزیابی مقاومت به قارچکش ها در جدایه های مختلف گونه های Botrytis از میزبان های متنوع در ایران

Due to population density and increasing demand for agricultural products worldwide, producers are trying to use different ways to minimize losses caused by pathogens, including Botrytis species. The most popular way to achieve the goal, especially in developing countries like Iran, is chemical protection. Therefore, we tried to obtain information about the response to fungicides in Botrytis cinerea, B. prunorum, B. sinoviticola and also Botrytis group S from strawberry (Alborz, Gilan, Isfahan, Kerman, Kurdistan, Mazandaran), raspberry (Gilan and Mazandaran) and rose (Alborz, Fars, Gilan, Hamedan, Isfahan). Six fungicides, Boscalid and Isophethamid (a SDHI, inhibitor of respiration) Fe(10 mgL-1), nhexamid (a SBI-III, inhibitor of sterol biosynthesis) (0.4 and 4 mgL-1 for detection of low and high resistance), Fluodioxanil (a Phenylpyrrole, inhibitor of signal transduction) (0.3 and 1 mgL-1 for detection of low and high resistance), Pyrimethanil (an Anilinopyrimidine, inhibitor of aminoasid and protein synthesis) (10 mgL-1) and Trifloxystrobin (an QOI, inhibitor of respiration) (10 mgL-1), due to frequent use and also being in the same group in terms of the mode of action and the most used fungicides in recent years in Iran against Botrytis were selected for the resistance test. The resistance level was measured based on the comparison of the growth of each isolate in the culture medium containing the fungicide with the growth of the control isolate. Despite the lack of positive correlation between fungicide response and virulence, isolates from all identified species were able to infect both strawberry and cucumber (as host plant) and included isolates with different levels of resistance to all six fungicides used. In general, the total number of isolates resistant to fungicides ranged from 4% for isophthamide to 47% for fenhexamide. In addition, unexpected strong resistance in 1 and 17% of isolates to Fludioxonil and Phenhexamide, which are not registered as botrytisicides in Iran, can be a big alarm for the chemical management of this fungus. The observation of predominance of isolates resistant to Trifloxystrobin, in contrast to other cases, can be justified by the high use of Pyraclostrobin (a fungicide of the same group, with a similar mode of action) in combination with Boscalid (under the name Sygnom). This study can provide a deeper insight into the risk of excessive use of fungicides and help control gray mold disease more effectively in Iran. It should be mentioned that among the genes related to resistance, only the status of cytB gene was investigated among isolates and the presence of intron in this region was confirmed for all isolates resistant to trifloxystrobin (with different levels of resistance).