COMPARATIVE EVALUATION OF CHEMICAL FUNGICIDES AGAINST SHEATH BLIGHT DISEASE OF RICE IN AMAN SEASON

Abstract

ABSTRACT Two experiments were conducted to evaluate the efficacy of chemical fungicides for the management of sheath blight disease of rice at Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during July 2019 to November 2019, following randomized complete block design (RCBD) and complete randomized design (CRD) with 3 replications for in vivo and in vitro experiments, respectively. Sheath blight disease susceptible variety BR 11 was used in these experiments. Fifteen treatments viz. T 1 (Tilt 250 EC), T 2 (Combi 230 EC), T 6 (

Awal 72 WP), T 10 (Sunvit 50 WP), T 14 (Contaf 5 EC), T 3 (Filia 525 SE), T 7 (Nativo 75 WP), T 11 (Control 1 (Folicur 250 EC), T 4 (Amister Top 325 SC), T 8 (Autostin 50 WP), T 12 ) and T 15 (Control 2 (Score 250 EC), T 5 (Acibin 28 SC), T 9 (Dithane M-45), T 13 ) were evaluated against Rhizoctonia solani causing sheath blight disease of rice (BR 11) in aman season. In field experiment thirteen fungicides and two controls were used, in which T 14 was with inoculation and T 15 was without inoculation. After the 4 th spray the lowest disease incidence per hill (30%), disease incidence per tiller (10.80%), disease severity (10.80%) and percent relative lesion height (%RLH), (2.44%) was found in T 2 treated plot. The highest disease incidence per hill (93.33%), disease incidence per tiller (44.71%), disease severity (48.36%) and %RLH (9.11%) was found in T 14

after the final spray. In case of yield contributing characters, the highest yield (6.94 ton/ha) and straw yield (7.12 ton/ha) was found in T 2 treated plot while lowest yield (3.49 ton/ha), straw yield (4.32 ton/ha) observed in T 14 . Moreover, T 3 were also significantly effective against this disease. In vitro condition at 1000 ppm concentration all fungicides 100% inhibited the mycelial growth of R. solani. At 250 ppm concentration six fungicides T 1 , T 2 , T 3 , T 4 , T 10 and T 11 completely inhibited the mycelial growth of R. solani. Among all, fungicides, T 12 gave the worst result to inhibit the mycelial growth of R. solani. and T 4