Mass multiplication and formulations of biocontrol agents for use against fusarium wilt of pigeonpea through seed treatment

Abstract

Trichoderma harzianum and Pseudomonas fluorescens are the two major fungal biocontrol agents found in the soil and the rhizosphere of various crop systems. We used different agricultural waste bases such as wheat bran, rice bran, paddy straw and neem cake for mass-multiplying T. harzianum and P. fluorescens. Ten isolates each of T. harzianum and P. fluorescens were isolated from rhizosphere soil samples collected from various pigeonpea-growing fields. We evaluated the efficacy of these isolates, both in increasing seed quality variables of pigeonpea and in inhibiting the mycelial growth of Fusarium udum Butler. Trichoderma harzianum isolate 4 and Pseudomonas fluorescens isolate 3 were selected and mass-multiplied using different agricultural waste products as bases. Among the latter, boiled rice bran was found to increase the growth of both biocontrol agents. Talc and sodium alginate formulations of mass-multiplied biocontrol agents were prepared and evaluated for their affects against fusarium wilt under greenhouse conditions. Fresh cultures of both biocontrol agents were found to increase seedling emergence and reduce fusarium wilt disease incidence when compared to the control and the formulations.