* To whom all correspondence should be addressed. E-mail: suneeag16@gmail.com JOURNAL OF PURE AND APPLIED MICROBIOLOGY, March 2017. Vol. 11(1), p. 241-247 Promissory Action of Trichoderma spp. and Fungicides in the Management of Fusarium Wilt of Gerbera P. Suneeta*, S. Vinod Kumar, K. Eraivan Arutkani Aiyanathan and S. Nakkeeran Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore - 641 003, Tamil Nadu, India. http://dx.doi.org/10.22207/JPAM.11.1.31 (Received: 14 September 2016; accepted: 03 November 2016) Novel Trichoderma harzianum isolate NVTH2, effective against Fusarium oxysporum f. sp. gerberae (FOG) causing wilt in Gerbera showed growth tolerance against azoxystrobin 23 % SC, kresoxim methyl 44.3% SC and carbendazim 50% WP at all the tested concentrations (50ppm, 100 ppm, 250 ppm, 500 ppm, 1000 ppm, 1500 ppm and 2000 ppm) followed by fosetyl Al 50% WP, difenoconazole 25% EC and tebuconazole 250 EC (effective against FOG) moderately tolerant at lower concentrations. The fungicides like propioconazole 25% EC, propineb 70 WP and tebuconazole 50%+ trifloxystrobin 25% WG (effective against FOG) completely resisted the growth of NVTH2. Finally, a field experiment was designed by utilizing 3 most efficient Trichoderma spp. and 4 fungicides in combination treatments. As a result, root dipping+ soil drenching with NVTH2 @5ml/ lit followed by soil drenching of tebuconazole @1ml/lit at fortnight interval alternately resulted in highest yield, growth promotion and percent inhibition of wilt incidence. Keywords: Fungicides, Gerbera, growth promotion, Trichoderma. Gerbera jamesonii Bolus ex Hook has very huge demand globally. The production of cut flowers has gone from 2,071 million stems in 2007 to 6,667 million stems in 2011, which ultimately increased the growth of domestic and export markets in India 1 . Deterioration of soil health makes Gerbera highly susceptible to soil borne diseases under protected cultivation. The major soil borne diseases of Gerbera are foot rot, wilt, root rot complex and blight 2 . Trichoderma harzianum is among the various species of the Trichoderma that is considered to be the utmost effective biocontrol agent 3 . The additive effects of Trichoderma and compatible fungicides were studied from many years. Arunasri et al. 4 reported that Trichoderma sp. which was effective against collar rot of crossandra were highly compatible with thiram (32% growth inhibition) and followed by captan (47.5%). Integration of Captan + Metalaxyl with Trichoderma harzianum and T. virens were found to be the superior to control the wilt complex of bell pepper caused by four wilt pathogens viz. Fusarium oxysporum, Phytopthora capsici, Rhizoctonia solani and Sclerotium rolfsii and promoted seedling growth 5 . MATERIALS AND METHODS Isolation, pathogenicity and identification of FOG Pathogen was isolated from the infected roots of Gerbera (var. Donavan yellow) on potato dextrose agar (PDA) medium amended with 1000 ppm of streptomycin sulphate. Surface sterilisation of infected root bits was done by 0.1% mercuric chloride (HgCl 2 ) solution for 30 seconds and