Title: Study on the fungicidal effects of VELGRO in controlling rice blast disease under field condition
Autore : Hadis shahbazi
Rice blast disease caused by Pyricularia oryzae is considered the most damaging disease of local rice cultivars in the north of Iran, so its chemical management has a special priority. In this study, the efficacy of VELGRO (34.5% Copper and 37.3% Zinc) in controlling leaf and panicle blast disease in comparison with Tricyclazole (75% WP) were evaluated in field conditions in a randomized complete block design with four replications. For this purpose, Hashemi seedlings were transplanted. Three concentrations of 0.5, 1, and 2 kg/ha of VELGRO and a concentration of 0.5 kg/ha of Tricyclazole were prepared and applied at the first appearance of disease symptoms in the region for leaf blast and after heading repeated for panicle blast estimation. Leaf and panicle blast disease percentages were assessed respectively 7 days after the first spraying and one week before harvest. After harvesting yield and yield components were measured. Statistical analysis was performed by using SAS software and an LSD test was used to show significant differences between treatments. After harvesting yield and yield components were measured. Statistical analysis was performed by using SAS software and an LSD test was used to show significant differences between treatments. The results showed that the concentration of two kg/ha of VELGRO not only reduced leaf, band, neck, and panicle blast disease by 25.77, 24.22, 38.44, and 8.41%, respectively, compared to the control, but also its efficacy in controlling of blast disease and its yield and yield components were very close to that of Tricyclazole. In yield components, although statistically, the percentage of filled and empty grains in Tricyclazole was higher and less than the concentration of 2 kg/ha of VELGRO, respectively, there was no significant difference between them in 1000-grains weight and yield/10 m2. Therefore, it seems that the concentration of 2 kg/ ha of VELGRO can be used in rice fields in rotation with other recommended fungicides for blast disease control and in the absence of predicting disease outbreaks, as well as in organic rice farming.
Keywords: Efficacy of fungicide, Tricyclazole, Chemical control, Organic rice, Fungicide resistance