SCLEROTIUM ROOT ROT OF SUGARBEET (Beta vulgaris L.): INCIDENCE, SEVERITY AND ITS IN-VITRO CONTROL THROUGH CHEMICAL, BOTANICAL AND BIOLOGICAL MEANS

Abstract

Incidence and severity of sclerotium root rot disease of sugarbeet was investigated at Sher-e-Bangla Agricultural University (SAU) and Bangladesh Sugarcrop Research Institute (BSRI) campus during January to March 2019. From the survey study it revealed that, the highest disease incidence (21.6%) was observed at BSRI farm, Iswardi in compared to SAU field (19.4%) and the disease severity was higher at BSRI campus (7.73%) compare to SAU campus (5.51%). The lab experiment was conducted for invitro management of sclerotium root rot disease of sugarbeet through chemical, botanical

and biological means during April to december 2019. Seven fungicides viz. Amister Top

325 SC, Acibin

28 SC, Tilt 250 EC, Ridomil Gold, Dithane M-45, Cabrio Top 55 WG, Benda 50 WP, one plant extract (Neem leaf) and two bio- agents (Trichoderma harzianum and Pseudomonus fluorescens) were evaluated for their efficacy against Sclerotium rolfsii. The selected chemical fungicides and neem leaf extract were evaluated following by cup method and two bio-agents were evaluated through dual culture method. Among the tested chemical fungicides, Cabrio Top 55 WG and Acibin 28 SC gave the better performance in controlling the radial mycelial growth of Sclerotium rolfsii. Amister top showed better Performance in reduction of radial mycelial growth (inhibition 70% over control) followed by Tilt 250 EC, Benda, Ridomil Gold, and Dithane M-45 (inhibition 64.78%, 64.11%, 18.56%, 14.44% over control respectively) at 4 days after inoculation. Neem leef extract was not found satisfactory result in reducing the growth of fungus in in-vitro. Between two bio-agents Trichoderma harzianum (% inhibition 42.77% over control) showed better performance in controlling Sclerotium root rot disease of sugarbeet compared to Pseudomonus fluorescens (% inhibition 27.60 % over control )in reduction of radial mycelial growth of S. rolfsii. In this study, the potentiality to cause sugarbeet root rot disease caused by Sclerotium rolfsii was also confirmed through pathogenicity test. However, from the findings of the in-vitro study, it may be concluded that among the selected chemical fungicides, Acibin 28 SC, Cabrio top 55WG and bio-agents Trichoderma harzianum can be suggested for field trail for management of sclerotium root rot disease of sugarbeet.