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

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

  • 摘要: 【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0.08 μg/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0.17~4.99 μg/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种药剂的毒力虽然较强但变异系数较大,对病菌存在较大的个体差异。各药剂对3种病菌的lgEC50相关性分析结果显示,吡噻菌胺、咪鲜胺和腈菌唑3种药剂间具有较高的交互抗性 (P<0.01);而吡噻菌胺和咪鲜胺分别与嘧霉胺、代森锰锌、嘧菌酯之间交互抗性较小。【结论】吡噻菌胺和咪鲜胺单剂分别与嘧霉胺、代森锰锌、嘧菌酯的复配剂可作为草果叶斑病类病害的新型低毒防控药剂在草果生态种植中推广使用。

     

    Abstract: 【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.

     

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