裸仁美洲南瓜白粉病菌对5种三唑类杀菌剂的敏感性研究

Sensitivity of hull-less pumpkin powdery mildew to five kinds of triazole fungicides

为明确裸仁美洲南瓜白粉病菌对丙环唑、腈菌唑、己唑醇、氟硅唑和戊唑醇5种三唑类杀菌剂的敏感性,在室内条件下,测定5种三唑类药剂对南瓜白粉病菌的毒力,结果表明:睛菌唑毒力作用最强,EC50值为62.11μg·mL^-1;戊唑醇作用最差,EC50值为1503.97μg·mL^-1;而氟硅唑、丙环唑和己唑醇的EC50值介于二者之间,分别为929.43、442.01和67.53μg·mL^-1。进一步探讨5种三唑类杀菌剂对裸仁美洲南瓜白粉病的防治效果和白粉病菌接种前后不同施药时间对白粉病菌的抑制作用,结果表明:12.5%腈菌唑对裸仁美洲南瓜白粉病的防治效果最佳(90.13%),25%戊唑醇防治效果最差(72.21%);白粉病菌接种前后不同施药时间对白粉病菌的抑制作用不同,接种后24h施丙环唑和腈菌唑最敏感,接种后96h施氟硅唑和戊唑醇最敏感,接种后48h施己唑醇最敏感。

In order to clear sensitivity of Podosphaera xanthii on hull-less pumpkin to five triazole fungicides (propi-conazole, myclobutanil, hexaconazole, flusilazole and tebuconazole), toxicities of the fungicides to P.xanthii were determined in laboratory. The results indicated that toxicitiy of myclobutanil had best effect, with EC50 value of 62.11μg·mL^-1, followed by flusilazole, propiconazole and hexaconazole, with EC50 values of 929.43, 442.01 and 67.53μg·mL^-1, respectively, and toxicitiy of tebuconazole (with EC50 value of 1503.97μg·mL^-1) was the lowest. The control efficacies of five triazole fungicides on hull-less pumpkins powdery and inhibition effects at different application times before or after inoculation with P. xanthii were also explored. The results showed that the myclobutanil 12.5% controlling effect (90.13%) was the best, the tebuconazole 25% control effect (72.21%) was the worst, and inhibition effects of fungicides at different application times were different before or after inoculation, the most sensitive times of propiconazole and myclobutanil were 24 hours after inoculation, flusilazole and tebuconazole were 96 hours after inoculation, hexaconazole was 48 hours after inoculation.