Biological Control of Tomato Damping-off by Gliocladium virens

Gliocladium virens (IMI No.304061) strongly antagonised Pythium aphanidermatum, incitant of tomato damping-off. G.virens hyphaeran parallel to, entwined around, penetrated into and killed the host hyphae. Cell-free culture filtrate of G. virens was inhibitory to P. aphanidermatum. Apron (5-25 ug/ml), Captaf (5-25 ug/rnl) and San S06F (50-150 μg/ml) completely inhibited the growth of P. aphanidermatum in vitro. Cobox L, Thiram and Captaf (5 g/Kg) seed) gave 64.28, 58.93 and 51.79 per cent control of tomato damping-off in .the glasshouse. G. virens was .relatively less sensitive to Apron (25 Ilg/ml), Captaf (150 Ilg/ml) , Cobox L (100 μg/ml) and Fytolan (100 Ilg/ml) -. Soil application of inoculum- rich mycelial and/or conidial preparation of G. virens on wheat-bran-saw dust (WBSD) media (3:1:3.5 w/w/v) (@ 10 g/2 kg soil) gave 82.77 % control of tomato damping-off. Seed coating with conidial suspension (3.78 x 10⁸ /ml) completely protected the seedlings in the glass house. Population of Pythium declined in soil amended with G. virens: Integration between WBSD preparation of the antagonist and fungicidal seed treatment yielded an additive effect of the two. Seed coating and soil amendment with G. virens separately resulted in 128.94, 162.38 and 107.89, 108.92 per cent increase in seedling stand over check in pre and post emergence phases respectively in the field nursery.