Effect of Trichoderma sp. on Sclerotium rolfsii, the Causative Agent of Collar Rot on Zamioculcas zamiifolia and an on Farm Method to Mass Produce Trichoderma species

The antagonistic effect of three local isolates of Trichoderma viride and one local isolate of Trichoderma harzianum were tested against the pathogenic fungus Sclerotium rolfsii. The latter organism is responsible for major loss due to collar rot of the ornamental crop Zamioculcas zamiifolia in Sri Lanka. The disease causes massive losses. The antagonistic potential of the local isolates against the phytopathogenic fungi Sclerotium rolfsii was investigated in dual culture, poison food technique, pot trials and field trials on Zamioculcas zamiifolia plants. All Trichoderma isolates tested under in-vitro conditions significantly inhibited the growth of S. rolfsii. Of these isolates, Trichoderma viride isolate Tv1, showed highest percentage inhibition and was thus selected for in vivo field trials. Data recorded from bi monthly field application of this organism over the two growing seasons, confirmed the success of the treatment in controlling collar rot disease at the economic threshold level. Field application of testing isolate T. viride Tv1 as a conidial suspension (1011 cfu mL-1) greatly reduced the disease incidence of Zamioculcas zamiifolia plants by a percentage of 75.54%. On farm mass production of this isolate was developed to help facilitate the establishment of an integrated eco-friendly disease management system for growers of Zamioculcas zamiifolia. Different media was also evaluated to mass produce the Trichoderma isolate. The media evaluated in this study included the solid substrates barley seeds, paddy, cow pea, maize and sorghum and semi solid, liquid substrates such as potato dextrose, rice extract, paddy extracts, respectively. Although mycelial growth was fastest in barley and paddy media. And the highest yield of spores of the Trichoderma isolate was observed 7 days after inoculation in Barley and Paddy media.