Biointensive management of blast disease of rice

Abstract

Blast of rice caused by Pyricularia grisea (Cooke.) Sacc. (Teleomorph :Magnaporthe oryzae) is a serious disease of rice and causes considerable reduction in yield. Overdose and untimely application of chemical fungicides disturb the rice ecosystem, pollute the environment and induce resistant mutants of the pathogen. An ecofriendly integrated disease management programme should be implemented to avoid overuse of a single control method and fight against genetic resistance. Salicylic acid (0.01ml/ l) and Benzoic acid (0.01ml/ l) proved superior in inducing disease resistance among different inducers tested at Regional Agricultural Research Station, Pattambi, Palakkdad district, under Kerala Agricultural University under green house conditions. As an integrated approach, Palmarosa oil + Carbendazim and Palmarosa oil+ Salicylic acid were the most effective treatments .Compatibility studies under in vitro conditions showed that Trichoderma harzianum and fluorescent pseudomonad were compatible to each other, and also palmarosa oil and Neemazal were compatible with Trichoderma harzianum and Fluorescent pseudomonad. For the management of blast disease under field conditions with high B:C ratio, Palmarosa oil (0.1%) + Carbendazim (0.1%)was the best treatment followed by Trichoderma (2%) + Fluorescent pseudomonad (2%)+ Palmarosa oil (0.1%).