Sensitivity of a biocontrol fungus, Beauveria bassiana strain GHA, to chemical fungi and bactericides on cucumber leaves

Abstract

The sensitivity of Beauveria bassiana strain GHA, an active ingredient in biocontrol agents, to chemical fungi and bactericides in plant leaves was investigated. Conidia of the GHA strain were mixed with 40 chemical agents registered in Japan and inoculated onto cucumber leaves. After a week of incubation, the rise and fall of the colony-forming units (CFUs) of the strain were measured. Many multisite activity inhibitors and sterol biosynthesis inhibitors decreased the CFUs of the strain. Fludioxonil, fluazinum, cymoxanil, fenexamide, benomyl, amisulbrom, mandipropamid, pyriofenone, polyoxins, fosetyl, flutianil, and kasugamycin decreased strain growth, in addition to sodium or potassium hydrogen carbonate in organic agricultural materials. When these chemicals are mixed to Beauveria bioagents, effects of the bioagents may be inhibited.