These SAR achievements with virus diseases in tobacco, papaya, chilli, potato and cucumber mean that promising results can be expected if SAR method is applied to RGSD and RRSD in rice. If successful, we can introduce this method to help farmers limit damage when they cannot avoid BPH at the beginning of crop. To reach this aim, the study was conducted in the net-house to find the best effective chemicals in SAR to RGSD if the rice plants were infected early, at 7 days after sowing. | JOURNAL OF SCIENCE, Hue University, Vol. 67, No. 4A, 2011 SELECTION OF CHEMICALS IN SYSTEMIC ACQUIRED RESISTANCE TO RICE GRASSY STUNT VIRUS Le Thanh Toan1 and Pham Van Kim2 1 College of Agriculture and Applied Biology, Cantho University 2 Vietnamese Phytopathological Society Abstract. The aim of this experiment is to select the best effective chemical to improve the health of rice grassy stunt disease infected rice plants. The experiment was conducted in the net-house of Plant Protection Department, College of Agriculture and Applied Biology (Cantho University), and was carried out with randomized complete design, 5 replications, 6 rice plants per replication. Rice grassy stunt disease was transmitted to rice plants at 7 DAS (day after sowing) with 3 larvae of rice grassy stunt virus borne brown planthopper/tiller. Rice plants were induced by seed soaking in 24 hours and then leaf spraying at 10, 20, 30 and 40 DAS. The experiment had 4 induced resistance treatments: (), K2HPO4 (20mM), oxalic acid () and combination of CuCl2 () + K2HPO4 (20mM). Results showed that rice plants in all four treatments had the height higher than those of infected control. Besides, these chemicals limited the quantity of infected plants, maintained the length of floccules, increased the ratio of firm grain and yield per pot. Among them, oxalic acid had the best systemic acquired resistance. Keywords: rice grassy stunt disease, Rice grassy stunt virus, systemic acquired resistance. 1 Introduction The epidemics of rice grassy stunt virus (RGSV) and rice ragged stunt virus (RRSV) have begun to cause serious damage in Vietnam since 2006. According to Plant Protection Department (2006), rice area seriously infected with RGSV and RRSV was 43, ha, with 14, ha destroyed in Summer Autumn 2006; and 62,224 ha infected with these viruses, with 2,321 ha destroyed in Autumn Winter 2006. Estimation of rice yield loss at the Mekong Delta was approximately .
