Fungicide Resistance Detection Of Botrytis Cinerea In Vegetable Fields And Its Resistance Risk Assessment Against Iminoctadine Tris

Grey mold is one of the most serious disease of vegetable crops, it is difficult tocontrol because Botrytis cinerea easily produces fungicide resistance. Therefore,resistance detection is useful to understand resistance level of Botrytis cinerea fromdifferent regions. In addition, the extension of a new fungicide also need to evaluatethe fungicide resistance to avoid or delay the resistance development. Based on this，the resistance of Botrytis cinerea in Shandong vegetable fields against4fungicides(diethofencarb, pyrimethanil, iprodione, fludioxonil) were detected, and the resistancerisk assessment of Botrytis cinerea agianst iminoctadine tris was conducted. Theresults are as follows:1. In this study,181strains of Botrytis cinerea from Shandong Province wereisolated, and their resistance frequency and resistance level against4fungicides weredetected with mycelia growth rate method. The results showed that pyrimethanil anddiethofencarb possessed high resistance frequency with90.61%and84.53%,respectively. The resistance frequency of iprodione is52.49%, and the resistancefrequency of fludioxonil is lower with18.23%. The detection of resistance levelshowed that no strain with high resistance was found. The strains with middleresistance against pyrimethanil, diethofencarb, iprodione and fludioxonil account for64.71%,36.78%,1.06%and0%, respectively. The average EC50value were33.9186±18.2906μg/ml,14.4168±17.5128μg/ml,3.6410±2.4229μg/ml and0.0659±0.0502μg/ml. And we found that pyrimethanil, diethofencarb and iprodionepossessed higher resistance frequency and lower resistance level. However,fludioxonil has better control effect with lower resistance frequency.2. The sensitivity of56Botrytis cinerea agaist iminoctadine tris were detected with mycelia growth rate method. The result showed that the iminoctadine tris hashigh inhibitory activity. The EC50value differ of26times. The average EC50value ofBotrytis cinerea is3.9226±2.1237μg/ml.3. Eighteen resistance mutants were got by UV and fungicide induction,including one high resistant strain, thirteen middle resistant strain, and4low resistantstrain. The resistance mutants were different from their parents in the biologicalcharacteristics. The results of cross resistance test show that iminoctadine tris has nocross resistance with diethofencarb, iprodione and fludioxonil.