EFFICACY OF SELECTED MODERN PHYTO- CHEMICALS AND Trichoderma harzianum AGAINST THE PATHOGEN OF SCLEROTIUM ROOT ROT DISEASE RESPONSIBLE FOR SUGARBEET DECLINE

Abstract

A field experiment on management of sclerotium root rot disease of sugarbeet was conducted in the central farm of Sher-e-Bangla Agricultural University, Dhaka during November, 2019 to March, 2020. The prime aim of the study was to manage the sclerotium root rot disease of sugarbeet using seven modern phyto- chemicals and bio- agent, Trichoderma harzianum. BSRI released tropical sugarbeet line HI 0044 was used as a planting material and seven modern phyto-chemicals viz., Amister Top 325 SC, Acibin, Tilt 250 EC, Ridomil Gold, Dithane M-45, Cabrio Top, Autostin were used in the experiment as a codified treatments. The sugarbeet was grown for sugar production and natural inoculums were relied upon for the infection of sclerotium root rot. Growth parameters, yield attributes and physiological features were significantly affected by the application of selected modern phyto-chemicals and bio- agent. Percent disease incidence and severity of sclerotium root rot was varied among the treatments. The lowest disease incidence (16.67, 13.89 and 16.67%) was found in Amister Top 325 SC, Acibin and Tilt 250 EC treated plots. The highest disease incidence (56.94%) was found in control treatment. The lowest disease severity (4.63, 4.63 and 5.40%) was found in Amister Top 325 SC, Acibin and Tilt 250 EC treated plots. The highest disease severity (14.20, 13.43 and 11.57%) was found in control treatment, Autostin and Dithane M-45 treated plots. Although the Acibin and Tilt 250 EC showed the better performance regarding the percent disease incidence and severity, but other considering parameters were not found at satisfactory level in Acibin and Tilt 250 EC treated plots due to the chemical effects. Plants were severely affected and showed the stunted and shrinked symptoms. The highest individual beet diameter, weight and yield per plot was obtained in Amister Top 325 SC, Dithane M-45, Cabrio Top and Autostin treated plots (41 cm, 1.02 kg, 24.40 kg; 32.28 cm, 0.78 kg, 18.80 kg; 33.38 cm, 0.85 kg, 20.40 kg and 32.58 cm, 0.85 kg, 20.40 kg respectively). The lowest individual beet diameter (19.75 cm), weight (0.51 kg) and yield per plot (12.16 kg) was obtained in control treatment. The highest brix (%) and sucrose/pol (%) was also measured in Amister Top 325 SC, Dithane M-45 and Cabrio Top treated plots (17.8 %, 12.7%; 16.9%, 12.62% and 16.9%, 12.62% respectively). The lowest brix (11.5%) and sucrose/pol (6.53%) was obtained in control treatment. However, from the findings of the study, it may be concluded that among the selected phyto- chemicals, Amister Top 325 SC and Cabrio Top showed the promising performance for management of sclerotium root rot disease of sugarbeet and gave better yield and yield attributes. On the other hand, bio- agent Trichoderma harzianum showed non-satisfactory results regarding the all considering parameters.