Biological Control of Seedling Diseases in Forest Nurseries in Kerala

Trichoderma harzianum, T. viride, and Psendomonas fluorescens were screened in forest nursery in two consecutive years to study the efficacy against the seedling damping-off pathogens, Rhizoctonia solani and Cylindrocladium quinqueseptatum. Solarization of nursery beds by tarping the moistened soil by thick polythene sheets was also carried out as a part of the experiment. The antagonists were introduced in the nursery beds by soil amendment and seed coating either singly or in different combinations using Eucalyptus tereticornis and E. grandis as the host plants. Solarization increased the temperature in the top layer of soil (2.5-5 cm depth) up to 51°C and reduced the pathogen inoculum considerably. Among various treatments, T. harzianum as soil application was the most effective one against damping-off followed by the combination of soil solarization and T. harzianum soil application.