POTENTIAL OF TRICHODERMA SPP AS CONSISTENT PLANT-GROWTH STIMULATORS

In a series of repeated trials, six Trichoderma spp. strains, applied as a dried powder from a liquid fermentation in molasses/yeast medium, proved to be consistent at promoting the growth of lettuce (Latuca sativa L.) seedlings grown in a peat-sand potting compost in the glasshouse. Strains WT, 92, 20, and 75 at 0.75% or 1% w:w concentrations increased shoot dry weight by up to 26%, although WT did inhibit germination. For example, after 4 days only 13% of seeds sown in WT 1% w: w treated compost had germinated, whereas in other treatments germination was consistently greater than 32%. WT increased shoot fresh and dry weights by 14.3 g and 0.6 g per pot, respectively, without affecting the root dry weights, to give concomitant increases in shoot: root ratios of fresh and dry weight. The potential use of these Trichoderma spp. strains for plant growth promotion is discussed.