EFFECT OF TRICHODERMA ON PLANT-GROWTH - A BALANCE BETWEEN INHIBITION AND GROWTH PROMOTION

The effect of lettuce (Latuca sativa L.) germination and growth in non sterilized potting compost of 0.1% and 1.0% w/w incorporation of ferme nter biomass inocula of six strains of Trichoderma was investigated. E xcept for strains WT and T35 at 0.1% w/w, all inocula inhibited germin ation. Biomass of strains WT, T35, 20, and 47 at 1.0% promoted shoot f resh weight, whereas strains TH1 and 8MF2 were inhibitory. In contrast , when biomass of strains WT, TH1, and 8MF2 was autoclaved and incorpo rated at 1%, shoot fresh weight was promoted, but the biomass of T35 w as inhibitory. None of the strains incorporated at 0.1% w/w increased shoot fresh weight, and autoclaved biomass of TH1, T35, and 20 incorpo rated at 0.1% w/w resulted in lower shoot fresh weights in comparison with.uninoculated controls. The shoot dry weight of lettuce seedlings could be enhanced by germinating seeds in uninoculated compost and aft er five days' growth transferring them into WT-inoculated compost. Ino culum of strain TH1 when applied using this method was very inhibitory . With WT the degree of increase in shoot fresh weight and germination rate declined as the fermentation time to produce inocula was increas ed.