Studies on Variability of Cassava Brown Streak Disease Symptoms and the Relationship between Virus Infection and Symptom Expression on Cassava Crop
For a long time, infected plants’ foliage and root symptoms were used to diagnose cassava brown streak disease (CBSD). However, because of the differences in symptom presentation patterns between types and seasons, symptom-based diagnosis has proven to be incorrect. The current investigation discovered three basic forms of CBSD symptoms in the foliage (chlorotic blotches, chlorotic spots, vein chlorosis) and root (brownish black necrosis, chalky necrosis, necrotic specks). Spotty foliage chlorosis, brown necrotic internal tissue at the base of the leaf petiole, and chalky root necrosis are among the newly identified CBSD symptoms. equally dispersed across the afflicted plants Plants that were both sick and visually seen to be infected by CBSV made as up to 67 percent of analysed samples. Only 7% were CBSV-infected but symptomless, while about 22% were free of CBSV despite appearing to have CBSD symptoms. Flowers, fruits, apical buds, young delicate leaves, newly-opened leaves, youngest symptomatic leaves, the tender top green region of the stem, and non-necrotic storage root tissues all tested positive for CBSV. According to the findings, symptom-based diagnosis for CBSD should include inspection of both leaves and roots, and should always be verified by molecular detection by RT-PCR.
Author (s) Details
Prof. Gration M. Rwegasira
Department of Crop Science and Horticulture, Sokoine University of Agriculture, P. O. Box 3005 Chuo Kikuu, Morogoro, Tanzania.
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