HIỆN TRẠNG VÀ TÁC ĐỘNG CỦA MỘT SỐ YẾU TỐ DỊCH TỄ ĐẾN BỆNH KHẢM LÁ SẮN (Begomovirus stanleyi) TẠI VIỆT NAM

Cassava mosaic disease is the most serious disease affecting cassava worldwide and its is caused by at least 11 viruses belonging to the genus Begomovirus. In Vietnam, cassava mosaic disease was first reported in Tay Ninh province in 2017 and rapidly spread throughout the country. The objectives of this study were to assess the status of cassava mosaic disease in major cassava-growing regions, identify epidemiological factors influencing the disease, and confirm its causal agent. Field surveys conducted in 2022 showed that cassava mosaic disease was present in 10 out of 12 surveyed provinces, with an average disease prevalence of 70.4%. The average disease incidence (DI), disease severity index (DSI), and adult whitefly (Bemisia tabaci) density were 75.4%, 2.80, and 2.51 individuals per plant, respectively. Statistical analyses revealed that: (i) cassava variety determined DI, DSI, and whitefly density; (ii) plant age influenced DSI; (iii) plants propagated from infected cuttings had higher DSI than those infected via whiteflies; (iv) adult whitefly density had a slight effect on DI but no effect on DSI. PCR testing of 507 cassava leaf samples and sequencing of 15 virus isolates confirmed that Sri Lankan cassava mosaic virus (Begomovirus stanleyi) was the sole causal agent of cassava mosaic disease in Vietnam at the time of investigation.