Impact of commonly used agrochemicals on different fungal and bacterial bio-agents

Abstract

Four fungal bio-agents viz., Trichoderma harzianum, T. viride, Paecilomyces lilacinus and Pochoniachlamydosporia and four bacterial bio-agents viz., Bacillus subtilis, B. pumilus, B. amyloliquefaciens and Pseudomonas fluorescens were tested for their in vitro compatibility with five fungicides (carbendazim, captan, mancozeb, copper oxychloride and fenamidone + mancozeb) and three pesticides (carbofuran, metam sodium and acephate) at recommended doses of the pesticides and fungicides. The results revealed that carbendazim and metam sodium were highly toxic to all fungal bio-agents and copperoxychloride, mancozeb, fenamidone + mancozeb and metam sodium were highly toxic to all bacterial bio agents. T. harzianum exhibited more tolerance to captan than T. viride, P. chlamydosporia and P. lilacinus. All fungal bio-agents exhibited tolerance to carbofuran and acephate except P. chlamydosporia. Carbendazim was comparatively safer to B. subtilis, P. fluorescens and B. pumilus, but more toxic to B. amyloliquefaciens. P. fluorescens was relatively tolerant and Bacillus spp. was more sensitive to carbofuran and acephate. This study suggests that it is safe to integrate fungal bio-agents with copper oxychloride, carbofuran and acephate and bacterial bio-agents (except B. amyloliquefaciens) with carbendazimin integrated pest management (IPM) programmes.