Risk Assessment Of Resistance Of Botrytis Cinerea To Penthiopyrad And Fluindapyr

Tomato gray mold,caused by Botrytis cinerea,is one of the most important plant diseases in this world.The severity of the disease is that it can occur in all stages of tomato crop growth,infecting all parts of tomato,and pose a great threat to the quality and yield of tomato.During 2018 to 2019,our laboratory collected some typical tomato gray mold leaves in Henan,Jiangsu,Shandong and other regions of China,and brought them back to the laboratory for separation.Nowdays,chemical control is still the main way to control the disease in China.However,due to unreasonable use of chemical pesticides for a long time,the problem of resistance of pathogens in the field resulted in the decline of drug efficacy.Therefore,the research and development of chemical pesticides for the prevention and control of tomato grey mould is of great significance for the long-term stable prevention and control of the disease.In this paper,the antimicrobial activity of SDHI against Botrytis cinerea was studied based on the samples of Botrytis cinerea collected in the laboratory.The sensitivity of 100strains of Botrytis cinerea to fluindapyr and penthiopyrad were determined by mycelial growth inhibition method and the baseline sensitivity was established.The resistance risk of fluindapyr and penthiopyrad to Botrytis cinerea was evaluated by laboratory acclimation of fluindapyr and penthiopyrad.Results are as follows:the sensitivity of the above of 100 isolates of Botrytis cinerea to fluindapyr and penthiopyrad was determined by mycelial growth inhibition method.Besides,The resistant mutants of Botrytis cinerea were obtained by laboratory acclimation.At the same time,the pathogenicity,temperature sensitivity and sporulation of susceptible and resistant strains,as well as the cross-resistance between resistant mutants and common fungicides,such as boscalid and azoxystrobinp,were determined to evaluate the risk of resistance to Botrytis cinerea.The results showed that the EC₅₀ value of Botrytis cinerea against fluindapyr ranged from 0.3922-3.8280μg/m L,the average EC₅₀value was 1.1974μg/m L,and the coefficient of variation was 9.76 times.Six strains of fluindapyr resistant strains were obtained by laboratory acclimation,and all of them were low resistance strains.The results of biofitness test showed that there was no significant difference in pathogenicity,temperature sensitivity and sporulation between the resistant and sensitive strains.The results of cross-resistance data showed that fluindapyr and boscalid had positive cross-resistance,while fluindapyr and azoxystrobinp had no cross-resistance.The risk level of resistance of Botrytis cinerea to fluindapyr was low.The EC₅₀ value of Botrytis cinerea against penthiopyrad ranged from 0.4399 to 3.4126μg/m L,the average EC₅₀value was1.5791μg/m L,and the coefficient of variation was 7.76 times.Six strains of penthiopyrad resistant strains were obtained by laboratory domestication,and all of them were low resistance strains.The results of biofitness test showed that there was no significant difference in pathogenicity,temperature sensitivity and sporulation between resistant and sensitive strains.The results of cross-resistance data showed that there was positive cross-resistance between penthiopyrad and azoxystrobinp,but no cross-resistance between penthiopyrad and azoxystrobinp.The risk level of resistance of Botrytis cinerea to pyrazolamide was low.