Evaluation of Fungicides and Bio-agent against Neck Blast Disease of Rice

Abstract

Blast disease caused by Pyricularia grisea, is one of the most devastating diseases of rice in most rice producing areas of the world. In Nepal, the disease causes 10%-20% yield reduction in susceptible varieties, but in severe case, it goes up to 80%. Chemicals are commonly applied for controlling rice blast disease, but when chemicals are used indiscriminately, they also pose a serious threat to the environment. An experiment was conducted to check the efficacy against neck blast disease of rice variety “DY-69” (a Chinese variety) with Hexaconazole 5 SC, Tricyclozole 76 WP and Kasugamycin 3% SL as chemical fungicides while with Trichoderma viridae as biological agent during June to November 2014 in experimental plot with four replications at Plant Pathology Division of Nepal Agricultural Research Council, Lalitpur. The treatments were applied two times in the field i.e. at tillering stage, i.e. 35 days after transplanting (DAT), and at booting stage, i.e. 65 DAT. Disease incidence, disease index, test weight and total yield were calculated and mean computed. Disease scoring of neck blast was done following the standard scoring system developed by SES (2002). Tricyclazole appeared better to control the neck blast disease followed by Hexaconazole determined in terms of disease incidence, disease index, test weight and total yield. However, T. viridae appeared quite comparable to tricyclazole. So, use of T. viridae as an option of bio-agent to control a disease will be ecofriendly measure and more study in its dose and application should be tested in field to verify the results and to control the blast of rice. Thus, using appropriate fungicide or bio-agents (alternative to fungicide) help in reducing health hazard by minimizing adverse impact on environment.