Indian Phytopath. 54 (1) : 67-71 (2001) Testing of different formulations of Gliocladium virens against chickpea wilt-complex A.K. TEWARI* and A.N. MUKHOPADHYAY** Division of Plant Pathology, GBPUAT, Pantnagar, Udham Singh Nagar 263 145 ABSTRACT: Out of seven different formulations of Gliocladium virens evaluated for their efficacy in preventing chickpea wiE-complex in glasshouse and field, six were found effective in controlling the disease. G. virens (Gv) remained viable in various formulations for three months at room temperature (20-3S0C) and six months at refrigerator temperature (SoC). The highest spore longevity (nine months) was observed with the formulation Gliocladium virens + Carboxymethyl cellulose. Seeds coated with various formulations were effective, except Gv+CaCO J in preventing chickpea wilt-complex in glasshouse and field. Of the various formulations, the preparation of Gv+CMC was found best in managing chickpea wilt-complex, Key words: Biological control, chickpea wilt-complex, formulations, Gliocladium virens, seed treatment Chickpea (Cicer arietinum) has been reported to be infected with a number of diseases. Among them chickpea wilt-complex is considered the most irnpor- tant,. devastating and challenging one, being respon- sible for seed rot, seedling blight, root rot and mature plant wilt, culminating in 60-70 percent yield loss. The disease is caused by several pathogens but Sclerotium rolfsii, Rhizoctonia solani, and Fusarium oxysporum f.sp. ciceri have been considered major pathogens (Nene, 1985). Chemical control of such soil-borne plant diseases is frequently ineffective because of the physi- cal and chemical heterogeneity of the soil, which may prevent effective concentrations of the chemical from reaching the pathogen. Biological control agent colo- nizes the rhizosphere, the site requiring protection, and leaves no toxic residues as opposed to chemicals. Spe- cies of Trichoderma and Gliocladium have exhibited promise in glasshouse and in field trials for the control of chickpea wilt-complex (Kaur and Mukhopadhyay, 1992; Mukhopadhyay and Mukherjee, 1991; Mukhopadhyay et al., 1992 and Mukhopadhyay, 1995). Successful biocontrol depends largely on the use of appropriate formulation and delivery system of effica- cious bioagents. Formulation is necessary to retain the viability during preparation, storage and ease of appli- cation and favour survival of bioagent in the environ- *Present Address: Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi 110 012 **Director, Tea Research Association, Jorhat, Assam ment. The present investigations, were carried out to generate potentially useful formulation of G. virens in controlling chickpea wilt-complex. MATERIALS AND METHODS Formulations of Gliocladium virens The antagonist Gliocladium virens Miller, Giddens and Foster, isolate-I (IM! No. 304061) from culture collections of Biocontrol Laboratory, GBPUAT, Pantnagar, was selected for the present investigations. The fungal antagonist was maintained on PDA slants at 5°C after growing for seven days at 28± 1"C. G. virens was multiplied on preboiled sterilized sorghum grains having 5 percent anhydrous dextrose. The in- oculated sorghum grains were incubated at 28±1°C for 15 days. Colonized grains were air dried, powdered and sieved with 80 mesh sieve. The concentration of conidia and chlarnydospores was determined using a haemacytometer prior to preparations of G. virens. The fine powder of G. virens was properly mixed with various adjuvants viz. clay soil (CS), multani soil (MS), talc powder (TP), calcium carbonate (CaCO), calcium sulphate (CaS0 4 ) and boric acid (BA) in a ratio of 1:1 w/w and with carboxymethyl cellulose (CMC) in a ratio of 3:1 w/w. These preparations were stored at 5°C for further studies. Compatibility of formulations Spore suspension from each preparation was made after one month. In each treatment one ml of spore