十一种杀菌剂防治马铃薯晚疫病的适宜施用时期

Optimal application timing of eleven fungicides for the control of potato late blight

为了明确当前市场上具有代表性的11种防治马铃薯晚疫病杀菌剂的适宜施用时期,采用人工接种马铃薯叶片的方法,测定了其中5种药剂在接种晚疫病菌前10 d内不同时间施用的预防效果和其中7种药剂在接种后24 h内不同时间施用的治疗效果。结果显示：在保证良好防治效果的前提下,药剂在病原菌接种前保护性施用的适宜时期比在接种后治疗性施用的适宜时期要长。在测试浓度下,接种前5种供试药剂保持100%防治效果的适宜施用时期为接种前3～10 d;而接种后7种供试药剂保持相同防效的适宜施用时期仅为接种后6～12 h,在生产实际中难以操作。研究结果说明,在田间马铃薯晚疫病的化学防治中,为了取得良好防治效果,每次用药均应在病菌侵入之前采用保护性施用,尽量避免在病菌侵入之后进行治疗性施用。

In this study, the optimal application timing of 11 representative fungicides for the control of potato late blight was investigated. The preventive effects of 5 fungicides applied at different time within 10 days before the inoculation（dbi） and the curative effects of 7 fungicides applied at different time within 24 hours post the inoculation（hpi） of Phytophthora infestans on potato leaves were tested by means of artificial inoculation. The result showed that, under the premise of achieving good control effect, the appropriate application period for fungicides protectively applied before the inoculation is much longer than that curatively applied post the inoculation. The optimal application period for 5fungicides applied before the inoculation, with 100% control efficacy, was 3 to 10 days under tested concentration; whereas that of 7 fungicides applied post the inoculation, with the same control efficacy,was only 6 to 12 hours, which is difficult to operate in actual potato production. The results of this study indicated that, in the chemical control of potato late blight in farming practice, spray should be conducted preventively before the infection of the pathogen, and curative application of fungicides should be avoided as much as possible.