草果叶斑病类致病菌对新型低毒药剂的敏感性及交互抗性

【目的】筛选高效防治草果叶斑类病害的绿色低毒药剂，为草果叶斑类病害的绿色防控和生态种植提供科学依据。【方法】以3种草果叶斑类病害(炭疽病、叶瘟病和叶斑病)的强致病菌[炭疽菌(Colletotrichum sp.)、灰梨孢菌(Pyricularia grisea)和茎点霉(Phoma sp.]为材料，采用菌丝生长速率法测定6种药剂(嘧霉胺、腈菌唑、咪鲜胺、代森锰锌、嘧菌酯和吡噻菌胺)对草果叶斑病类致病菌株的敏感性和毒力变异系数；通过药剂间交互抗性分析，筛选具有较好协同作用的药剂组合。【结果】吡噻菌胺和咪鲜胺对炭疽菌和灰梨孢菌的毒力最强，与其他药剂的半最大效应浓度(EC₅₀)差异显著(P<0.05)，其中吡噻菌胺和咪鲜胺对炭疽菌的EC₅₀平均值分别为0.04和0.08μg/mL，吡噻菌胺对炭疽菌菌丝生长抑制率均在61.68%以上，最高达93.57%。6种药剂对茎点霉均具有较高毒力，EC₅₀介于0.17～4.99μg/mL，其中咪鲜胺和嘧菌酯的毒力最强。6种药剂对3种病原菌的毒力变异系数分析结果显示，吡噻菌胺和咪鲜胺2种...

Sensitivity and cross-resistance of pathogen of Amomum tsao-ko leaf spot to new low-toxic fungicides

【Objective】 To screen environmentally friendly low-toxic pesticides to prevent and control leaf spot diseases of Amomum tsao-ko，so as to provide scientific basis for A.tsao-ko leaf spot prevention and control and planting of A.tsao-ko.【Method】 Pathogens of 3 kinds of A.tsao-ko leaf spot（anthracnose，leaf blast and leaf spot disease），Colletotrichum sp.，Pyricularia grisea，and Phoma sp.were taken as material.Mycelial growth rate method was used to determine the sensitivity and virulence coefficient of variation of 6 medicaments（pyrimethanil，myclobutanil，prochloraz，mancozeb，azoxystrobin and penthiopyrad）；through cross-resistance analysis between medicaments，combinations of medica-ments with better synergistic effects were screened.【Result】Penthiopyrad and prochloraz had the strongest virulence to Colletotrichum sp.and P.grisea，and their EC₅₀ was significantly different from that of other medicaments（P<0.05）.The average EC₅₀ values of penthiopyrad and prochloraz against Colletotrichum sp.were 0.04 μg/mL and 0.08 μg/mL，respectively，mycelial growth inhibition rate of penthiopyrad on Colletotrichum sp.was above 61.68%，and its highest value was 93.57%.Six medicaments had strong virulence to Phoma sp.，with a EC₅₀ of 0.17-4.99 μg/mL，among which prochloraz and azoxystrobin had the strongest virulence.The results of virulence variation coefficient analysis of 6 medicaments against 3 pathogens showed that penthiopyrad and prochloraz had strong virulence，but their variation coefficients were high，indicating they worked differently for pathogens.Based on the correlation analysis of the lgEC₅₀ of penthiopyrad，prochloraz and myclobutanil，these 3 medicaments had high cross-resistance（P<0.01）；penthiopyrad and prochloraz had little interaction resistance with pyrimethanil，mancozeb and azoxystrobin.【Conclusion】Compound agent of single agent of penthiopyrad or prochloraz with pyrimethanil，mancozeb and azoxystrobin can be used as a new low-toxicity control agent for prevention and control of A.tsao-ko leaf spot in planting.