Improving Efficacy of Fungicides with Integration of Plant Products and Resistance Inducers for the Management of Rice Blast

摘要

Experiments were conducted during 2008-2011 for the management of rice blast caused by using fungicides plant products and resistance inducers. Based on the studies, promising fungicides isoprothiolane (1.5ml L (1)), carpropamid (1ml L (1)), carbendazim (1.5g L (1)), propiconazole (1ml L (1)) and tricyclazole (0.6g L (1)) were evaluated in integration with plant products- palmorosa oil and neemzal, and resistance inducers - salicylic acid and benzoic acid in a pot culture. Isoprothiolane and carpropamide singly and combinations of palmarosa oil + carbendazim, neemazal + carbendazim, salicylic acid + carbendazim, showed enhanced efficacy in suppressing the disease. In the field trial, palmarosa oil + carbendazim had the highest B: C ratio of 2.69, which was exactly the same as in the case of Isoprothiolane. This was followed by neemazal + carbendazim, salicylic acid + carbendazim, and carpropamid and fungicidal check. The efficacy of carbendazim was improved by integrating it with palmarosa oil or neemazal or salicylic acid, which was as effective as isoprothiolane. The relationship between blast disease severity and weather factors during kharif 2010 indicated positive correlation between disease severity and maximum temperature, RH, rainfall, and rainy days, but negative correlation with minimum temperature. With an increase of one unit of maximum and minimum temperature, RH and rain fall, the percentage of disease index increased by 3.23, 2.29, 2.27 and 0.07, respectively. The judicious use of integrated treatments according to disease prediction system would be useful for reducing the losses caused by rice blast.