abstract
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Wheat blast is an emerging and one of the most damaging disease to the last decades. After 31 years of its emergence in Brazil, the first outbreak of this disease outside South America was recorded in Bangladesh in 2016 with significant yield damage conferring a global concern in the wheat stakeholders. This outbreak represents a serious threat to wheat production not only for Bangladesh but also for other countries with similar agro-climatic conditions. Reliable and effective disease management strategies are needed for managing this disease. Blast disease control using a single option is unlikely to be effective and sustainable, and therefore, a number of studies with different strategies were conducted for effective management of wheat blast. Wheat planted in optimum timing of November 15-30 mostly escaped or had very low disease intensity while it increased with the late sowing dates of December 15 to January 4. The highest disease severity of 85.92% was observed with highly susceptible variety BARI Gom 26, while the resistant variety BARI Gom 33 showed only 0.96% disease severity under late sowing condition. In a field screening experiment comprising a total of 408 diverse germplasm and 25 advance lines including check varieties were evaluated for wheat blast reaction under natural and artificially inoculated conditions. Some of the promising lines had immune or low infection ranging from 0 to 10%, while the susceptible check varieties showed up to 92% disease severity. From this study, Borlaug 100, and the elite breeding lines BAW 1272, BAW 1280 and BAW 1286 were found most promising against wheat blast. Seed treatment with Provax 200 WP (Carboxin 37.5% + Thiram 37.5%) and some other group of fungicide completely controlled seed infection of MoT and improved germination and plant growth, while the untreated seed showed 45-50% seed infection with reduced germination and poor plant vigor. Preventive foliar spray with fungicides was found to be effective against wheat blast infection with significant reduction in disease severity and increase in grain yield and economic benefit. Combination of triazole with strobin was found more effective for controlling the disease (upto 95%). Thus, timely planting, seed treatment and preventive foliar spray with fungicide have been suggested as a short-term measure until resistant varieties are made available to farmers.