Evaluation of fungicides about residue, rainfastness and efficacy of disease inhibition for the purpose of efficient control to the anthracnose with Colletotrichum gloeosporioides on Japanese pear

Abstract

Azoxystrobin, dithianon, fluazinam, kresoxymmethyl, captan-benomyl were evaluated for residue, rainfastness and efficacy of disease inhibition by spraying Japanese pear leaves after inoculation with Colletotrichum gloeosporioides, and efficacy in the field condition to establish an efficient control system against anthracnose on Japanese pear leaf. Azoxystrobin and dithianon were more efficient than the other three fungicides and maintained a protective value of about 80 (80% disease suppression over control) until 14 days after spraying in the field. Both fungicides also maintained the same protective value when cumulative precipitation was less than 200mm in an artificial precipitation experiment. These characteristics of dithianon and azoxystrobin explain why they continuously had higher control efficacy than other three fungicides during three years of field tests. Among the five fungicides, azoxystrobin was the most efficacious when sprayed 2 days after inoculation with the pathogen. This result suggests that azoxystrobin can be used as a fungicide for post-infection application.