Fungal Antagonists for the Biological Control of Ascochyta Blight of Chickpea

Abstract

Ascochyta blight (Ascochyta rabiei) is one of the most devastating diseases of chickpea. The biocontrol potential of fungal antagonists, Chaetomium globosum, Trichoderma viride, Acremonium implicatum were explored under in vitro and in vivo. A. implicatum isolate-1 overgrew the host mycelium and caused lysis, while A. implicatum isolate-2 produced inhibition zone. C. globosum profusely overgrew the mycelium of A. rabiei and T. viride showed overgrowth and profuse sporulation. Bioassay with culture filtrates of all the antagonists resulted in significant inhibition of pycnidiospore germination and reduction in colony development of A. rabiei. Syringe filtered culture filtrate when amended in liquid broth medium also significantly reduced the mycelial growth. Bioassay of culture filtrates under glass house conditions, although brought reduction in disease development in both pre- and post-inoculation sprays, but C. globosum was the most effective antagonist causing 73.12% reduction in disease index when used as post inoculation spray. Under in vitro conditions C. globosum caused 48.59% reduction in colony diameter and 70.86% reduction in pycnidiospore germination.