Indian Phytopath.dcbaZYXWVUTSRQPONMLKJIHGFEDCBA 59 (1) : 68-71 (2006) Sio-efficacy of fungicides against different fungal bioagents for tolerance level and fungistatic behaviour K.K. PANDEY*, P.K. PANDEY and K.K. MISHRA Indian Institute of Vegetable Research, Varanasi 221 005 ABSTRACT:Newgeneration fungicides are most frequently used in vegetable crops as seedtreatment,soil drenching and foliar sprays. Thesefungicides havenot beentested so far against Trichoderma spp.andthe information isstill lacking aboutthetoxicity ofthesefungicides againstdifferent antagonists. Presentstudies revealed tolerance limit of the test fungicides by various biocontrol agents for compatibility. Complete inhibition of all the four species of Trichoderma is observed by tebuconazole and hexaconazoleshowing extremely toxic nature of the fungicide. Captanand propineb show tolerable growth up to 200).1grnl' while azoxystrobin at400).1grnl'. Among thesefungicides ml· 1 azoxystrobin is lesstoxic and compatible upto 400 ).1gml', Captan is fungistatic to T. harzianum and can be applied by keeping 2-3 days gap betweenthe fungicide and bioagentas integration. Combination of soil treatment by captan followed by afew daysseed treatment laterwith Trichoderma would bevery safe and useful without any loss of Trichoderma. Thelevel ofthe fungicidal toxicity varied amongdifferent biocontrol agents.Captan,propineb andazoxystrobin canbe integrated between200-400).1gml' concentrations depending upon the speciesof Trichoderma. Pencycuron can beincorporated with Trichoderma even at a concentration of morethan 400).1grnl' for seedtreatment in the integratecimanagementsystem. Key words: Bioagents,fungicides,integration, Trichoderma Search for potential biocontrol agents for the management ofplant diseases has been intensified in recent years to reduce the dependence on ecologically hazardous chemicals. Itmay be even better ifthe biocontrol agent is effective as well as compatible with seed and soil dressing fungicide so that it can be used in integrated disease management system. Insuch approach, biocontrol agents need to be used with fungicides without any toxic effect on antagonists (Papavizas and Lumsden, 1980). Such type ofcompatible fungicide can be mixed with the antagonists for the management ()f diseases. Use of some strains of Trichoderma harzianum tolerant to fungicides has been reported for the integrated control of plant diseases (Papavizas et a/ 1982). Integration of foltaf at 0.125 percent concentraion with G. virens as seed treatment was used for control of chickpea wilt disease (Upadhyay and Singh, 1995). T *Corresponding author: koshlendra_pandey@rediffmail.com harzianum and T viride cannot be integrated with carbendazim even at a concentration of 10).,lgrnl' while thiram can be used up to 50 ).,lgrnl' (Pandey and Upadhyay 1998). Several new generation fungicides ofergestoral biosynthesis inhibitorgroups (EBI) are highly specific to the pathogen. These new fungicides are nowadays most frequently used invegetable crops as seed treatment, soildrenching and foliar sprays. These fungicides have not been tested so far against Trichoderma spp. and the information is still lacking about the toxicity of these fungicides against different antagonists. Therefore, the present investigation was carried out to find out the tolerance limit ofdifferent fungicides by various biocontrol agents for use in integrated disease management programme. MATERIALS AND METHODS Eight fungiCides, viz., Kavach 75 WP (chlorothalonil), Captan 50WP (hetrocyclic nitrogen compound), Monceren 250 FS (pencycuron), Contaf 5% SE (hexaconazole), Folicur (tebuconazole),