Characteristics of Three Trichoderma Species in Peanut Haulms Compost Involved in Biocontrol of Cumin Wilt Disease

Peanut haulms compost as a carrier of three Trichoderma species (T. harzianum, T. hamatum and T. koningii) exhibited different morphological and chemical characteristics and its ability to control Fusarium wilt of cumin plants caused by Fusarium oxysporum compared with peat/vermiculite. The peanut haulms carrier was able to increase the population size, numbers, viability, survival, microbial biomass and activity during twelve months experiment while population from other commercial peat/vermiculite was decreased. Detecting Trichoderma biochemical activity in compost by High Performance Liquid Chromatography (HPLC) analyses revealed that relative amounts of antibiotics as gliotoxin, trichodermin and gliovirin as well as total phenols production increased. At the same time, spectrophotometric determination of the enzymatic hydrolysates revealed that chitinase, protease, cellulase, βglactosidase and β-1,3-glucanase were also increased. In infested and natural soil with Fusarium oxysporum, amendment with peanut haulms compost inoculated with Trichoderma spp. were found to be effective in reducing wilt disease incidence and pathogen population. Addition of peanut compost increased the population counts of all Trichoderma spp in soil. Plant growth yield, nitrogen content and seeds oil content were improved. Peanut compost inoculated with T. harzianum was effective in reducing disease incidence and increased yield components. Similarity between levels and specificities of biological activity and the morphological and chemical characterization of biocontrol agents in compost were found in relation to antagonist. Peanut haulms compost, in general, exhibited high stimulation of biocontrol activity.