西南冷凉产区苹果黑星病流行规律初探及防控药剂筛选

Preliminary study on the epidemic regularity of apple scab in the cool areas of southwest China and screening of control fungicides

2021年以来,苹果黑星病在西南冷凉高地部分苹果产区暴发。为了探索出苹果黑星病在西南冷凉产区的发生规律和筛选出防控效果较好的药剂,以云南昭通苹果产区5年生瑞雪苹果为材料,调查黑星病发病规律及其同气候变化的关系,并通过田间药效试验测试了11种杀菌剂对苹果黑星病的防治效果。结果表明,3月下旬至4月初昭通地区降水后,苹果黑星病菌越冬孢子开始萌发并侵染,4月底至5月初开始显症,之后因雨水增多和温度适宜而快速发病,6月底达到发病高峰,进入7月后病情因雨水减少、气温较高和叶片成熟而趋于稳定。在供试的11种药剂中,40%嘧霉胺SC(1000倍液)、20%氟唑菌酰羟胺SC(3500倍液)、50%醚菌酯WG(2500倍液)和40%氟硅唑EC(6000倍液)的防治效果较好,末次药后20 d均在93%以上;30%吡唑醚菌酯SC(2500倍液)和30%氟菌唑WP(3000倍液)、10%苯醚甲环唑WG(2000倍液)、40%氯氟醚菌唑SC(1500倍液)、50%氟醚菌酰胺WG(3500倍液)的防治效果中等,末次药后20 d在68%~79%之间,其余药剂防治效果较差。

Since 2021,apple scab was outbreak in some apple producing areas in the cool highlands of southwest China.In order to explore the occurrence regularity of apple scab and screen out effective prevention and control fungicides,five-year-old Ruixue apple was used to investigate the occurrence regularity of apple scab and its relationship with the climate change,and effect of 11 fungicides on apple scab was tested with field test.The results showed that the overwintering spores of apple scab began to germinate and infect the plants in mid-late March in Zhaotong areas,and the primary symptom on leaves was observed at the end of April and the beginning of May,then the rate of infected leaves increased exponentially with the increase of rainfall and reached the peak at the end of June,finally became stable with the decrease of rainfall and the maturation of leaves.Among the 11 fungicides,40%pyrimethanil SC(1,000 times liquid),20%pydiflumetofen SC(3,500 times liquid),50%kresoxim-methyl WG(2,500 times liquid)and 40%flusilazole EC(6,000 times liquid)showed the best control effects.After 20 days of the last spray,the control effect remained above 93%.The control effects of 30%pyraclostrobin SC(2,500 times liquid),30%triflumizole WP(3,000 times liquid),10%difenoconazole WG(2,000 times liquid),40%mefentrifluconazole SC(1,500 times liquid)and 50%Fluopimomide WG(3,500 times liquid)were moderate,from 68%and 79%at 20 days after the last spray.The control effects of other fungicides were lower.