Gliotoxin, an epithiodiketopiperazine toxin produced by the "Q" strain of Trichoderma virens, is essential for curtailing growth and multiplication of phytopathogens (Howell et al. 1993, Fravel 1988). Three isolates (Gv, Gv-A and Gv-V) of Trichoderma virens were grown on natural substrates such as bengal gram hull, gingelly cake, green gram hull, rice bran, soya meal, sugarcane bagasse, soyameal + tapioca, tapioca powder, tapioca peel and wheat bran). It was evident from this study that maximum gliotoxin (64 mg/l) was produced on tapioca powder by the alien isolate Gv. However sugarcane bagasse significantly enhanced gliotoxin production (36 mg/l) in the native isolate Gv-A, when compared to other substrates like green gram hull and rice bran. So far, studies on production of gliotoxin on synthetic media has been reported. We report the production of gliotoxin by T. virens on natural substrates "in vitro" for the first time.

Mimosine, a non-protein aromatic amino acid was tested at 100, 50 and 25 microg/mL on some human pathogenic bacteria and fungi. Mimosine exhibited total lethality towards Trichophyton tonsurans and Trichophyton rubrum at 100 microg/mL. Among the tested bacteria Staphylococcus aureus was inhibited to a larger extent than the other bacteria. The studies revealed mimosine to be potent against fungi rather than bacteria. This study reports the effect of mimosine on dermatophytes for the first time.

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The present investigation was carried out at Sugarcane Research Station, Cuddalore on CoC25 sugarcane variety during the period of 2016-2019. This study was conducted to determine the effect of silicon nutrition on physiology, yield and quality of sugarcane under drought condition. Result showed that soil application of silica solublizer @ 12.5 kg + 50 kg FYM/ha + sett treatment with 0.5% K 2 SiO 3 + 2.5% urea and potash foliar spray on 15 days interval from 60 to 150 DAP showed maximum germination percentage, tiller population, leaf area, millable canes, relative water content, silica solubilizing microbial count, total chlorophyll content, nitrate reductase activity, catalase, proline, plant height, number of nodes, internode length, silicon content, carbon content, potassium content, single cane weight, commercial cane sugar per cent, cane yield and sugar yield under drought condition in both plant and ratoon crop.