Biological management of fusarial wilt of tomato by Trichoderma spp. in Andamans

Abstract

Twelve isolates of Trichoderma from Andaman and Nicobar Islands have been evaluated for their biocontrol potential under in vitro and field conditions during 2008-09, 2009-10 and 2010-11 against Fusarium oxysporum f. sp. lycopersici causing wilt of tomato. The isolates Th-CARI-50, Tv-CARI-73, Tv-CARI-85 and Th-CARI-61 were most efficient in the hyperparasitic action on the test pathogen in dual culture test. The biopriming of seeds with Trichoderma isolates and bacterial antagonist significantly improved the germination behaviour of tomato seeds as compared to control. Mycelial form of inocula was proved better than conidial inocula of Trichoderma in inducing germination (%) of tomato seeds. The isolates Th-CARI-61 was proved most effective in inducing per cent germination (90% - mycelial inoculums; 88% - conidial inocula), seedling vigour (945 – MI; 889 - CI), seedling biomass (395.5 mg - MI; 355.4 mg - CI) of tomato seedlings followed by Tv-CARI-85, Th-CARI-50, Tv- CARI-73, P. fluorescens, Tv-CARI-110, Th-CARI-72, whereas Th-CARI-130 was noted with least effective. The seed and soil application of Trichoderma spp. was most effective in reduction of disease incidence of fusarial wilt of tomato under both greenhouse and field conditions than that of either seed or soil application alone. Th-CARI- 50 was most effective in inducing germination (92%), lowest disease (16.4%) and highest reduction of disease incidence (80%) followed by Th-CARI-61, Tv-CARI-85, Tv-CARI-73, Th-CARI-130 and the isolate Tv-CARI-100 was least effective (54.9% RDI). T6 treatment (Th-CARI-50) was most effective in improving field emergence (90.2%) of tomato seedlings, reduction in fusarial wilt disease incidence (78.8%) and corresponding yield increase (138%) of tomato under field condition followed by T12 (Tv-CARI-73), T15 (Tv-CARI-85) and T3 (Th-CARI-61).