The effects of addition of Trichoderma inocula on flowering and shoot growth of bedding plants

Abstract

Trichoderma isolates were added to a range of peat-based growing media as a dried fermenter biomass to study the prospects of general use in promoting bedding plant growth. The responses of marigold plants in peat/grit compost, petunia plants in peat/sand compost and verbena plants in Fisons M2 compost to inoculation with a range of Trichoderma strains applied as dry fermenter biomass were studied. In tests with marigold seedlings, T. harzianum strains WT, T35 and 20 and T. viride strain 47 applied at a rate of 1% w/v showed increases in shoot fresh and dry weights of up to 40% and 52%, respectively, and T. harzianum strains T35 and 20 increased the number of flowers by up to 40%. In tests with petunia plants, T. harzianum strain TH1 applied at a rate of 0.1% w/v increased the shoot fresh weight by 82% and dry weight by 87%. The number of flowers and buds were increased with strain TH1 at application rates of 0.1% and 0.01% w/v and with T. harzianum strain T12B applied at a rate of 0.1% w/v by up to 227%. In tests with verbena seedlings, T. harzianum strains WT and 20 and T. viride strains 75, 92 and T8 were applied at 0.3, 0.7 and 1.0% w/v. Depending on concentration, each strain was able to increase either number of flowers, weight of flowers, shoot fresh weight or shoot dry weight, but only WT applied at 1% w/v increased all these parameters. Thus Trichoderma biomass can increase flowering and shoot growth of petunia, marigold and verbena under a range of cultural conditions.