Trichoderma as a Seed Treatment to Control Helminthosporium Leaf Spot Disease of Chrysalidocarpus lutescens

Helminthosporium (Bipolaris) causes a leaf spot disease in Chrysalidocarpus lutescens (cane palm) in Sri Lanka. The losses could reach 90% of production during rainy weather conditions. Field experiments were carried out to test the efficacy of treatment of seeds of C. lutescens against Helminthosporium infection. In the fungal growth tests the isolates T.harzianum 1, T.harzianum 2, T.viride 1,T.viride 2 and T.viride 3 inhibited growth of the pathogen by 79.18, 69.03, 83.75, 82.99, 74.11% respectively. Isolates of Trichoderma harzianum and Trichoderma viride obtained from soil and having antagonistic activity against Helminthosporium were used in the field experiments. In the field trials, seed treatment with a spore suspension of Trichoderma completely eliminated the disease while Trichoderma and Pseudomonas fluorescens reduced the disease incidence significantly. The seed treatments also significantly increased seed germination, seedling growth and seedling vigor.