کارآیی قارچ‌کش بیولوژیک پروبیوتکت در کنترل بیماری بلاست برنج در خزانه

Blast is the most important fungal disease of rice in humid areas, including Mazandaran province, which in favorable conditions causes up to 90% of crop loss in local cultivars. The rice plant is exposed to (Pyricularia oryzae) at all stages of its development. The aim of this study was to evaluate the efficiency of Probiotect biological fungicide in controlling rice blast disease by seed coating on Fajr and Hashemi cultivars in the seedbed. Probiotect contain densities of 107 to 108 colony forming units (CFUs) from the live strain of the plant probiotic bacterium Bacillus subtilis UTB96. This research was conducted in April 2019, in Hadishahr region in Mazandaran province, as a factorial experiment, in the form of a randomized complete block design with four treatments and in three replications in plots measuring 2×6 m in a traditional seedbed with an area of 434 m2. Efficiency of compound was calculated based on Abbott's formula by measuring two indices of incidence and severity of leaf blast disease in control plots (water) and treatment (Probiotect) when the incidence of disease in the control reached 90%. Disease severity was measured on a scale of nine (9) by the International Rice Research Institute of the Philippines (IRRI, 1996). The results of analysis of variance of the obtained data showed that the effect of cultivar, biological compound and interaction of cultivar and compound on efficiency based on the incidence and severity of rice blast disease was statistically significant at the level of statistical probability of 0.1%. The highest efficiency of Probiotect based on both incidence and disease severity indices was 70.28 and 60.54%, respectively, for Fajr cultivar, compared to Hashemi cultivar, 34.93 and 24.25%, respectively. Probiotect showed 50.30% incidence efficiency and 59.94% efficiency showed more intensity on Fajr cultivar compared to Hashemi. As a result, Probiotect on Fajr semi-sensitive cultivar, in comparison with Hashemi sensitive cultivar, had an incidence efficiency and intensity of more than 50% in controlling leaf blast in the seedbed.