INTEGRATED APPROACH FOR THE MANAGEMENT OF FOOT AND ROOT ROT DISEASE OF BETELVINE (PIPER BETLE L.)

Abstract

Betelvine (Piper betle L.) is an important cash as well as exporting crop of Bangladesh. The crop is attacked by various diseases. Of those foot and root rot caused by Sclerotium rolfsii is the most devastating one, which causes considerable losses of the crop in the country. An investigation was undertaken to develop an integrated disease management (IPM) approach against the disease. Preliminary experiments were conducted to find out present severity status of the disease in major betelvine growing areas of Bangladesh, to select IPM components and finally to evaluate the efficacy of integrated application of the selected IPM components against the disease. It was found that incidence of the disease in five upazillas varied within range of 5.60 – 28.80, 4.00 – 10.40 and 4.00 – 7.20% in late summer (August), late winter (February) and midsummer, respectively. The maximum incidence of 15.46% was recorded from Gournadi where soil pH was 5.4, air temperature 32.61 o C, RH 82.46 and light intensity 53x100 lux, and the lowest incidence of 4.53% from Sitakunda where soil pH 6.6, air temperature 28.78 o C, RH 72.67% and light intensity 74x100lux. Other than foot and root rot disease leaf spot or anthracnose (Colletototrichum piperis), leaf rot (Phytophthora parasitica) and stem rot (Phytophthora parasitica) were recorded from different upzillas. An experiment was conducted to identify the isolates of S. rolfsii isolated from foot and root rot infected betelvine plants collected from different areas of Bangladesh. Altogether 19 isolates of S. rolfsii were found to be associated with foot and root rot infected betelvine plants in different locations. The mycelial growth, colony colour, colony consistency, formation of sclerotia, number, shape, size and colour of sclerotia varied remarkably among the isolates. All 19 isolates were pathogenic. The most pathogenic isolate was isolate-9 from Kaligonj upazilla of Jhenaidah. Thirteen betelvine cultivars designated as PB 001 to PB 013 were collected from different locations of Bangladesh and found remarkable variations in vegetative growth, morphological features and disease reaction. Based on incidence of foot and root rot (8.33-100.00%) on those cultivars, PB 001 was graded as resistant, PB 011 and PB 013 as moderately susceptible and rest of ten cultivars as susceptible. In-vitro and in-vivo experiments were conducted and based on promising results, four chemical fungicides (Provax 200, Tilt 250 EC, Score 250 EC, Pencozeb 80 WP), two plant extracts (garlic clove, Allamanda leaf), two soil amendments (poultry manure, Vermicompost) and a bioagent (T. harzianum) were selected as IPM components. Efficacy of integrated application of those IPM components, in 22 treatment combinations including a control, was evaluated under inoculated conditions to control foot and root rot of betelvine. Visible symptoms of the disease did not appear on the betelvine plants up to 120 days after inoculation (DAI) under the treatment with T. hazianum + Provax-200. The first visible symptoms of the disease appeared within 9 to 116 DAI under other treatments. At 120 DAI, the maximum reduction of disease incidence of 100% was found under

under other treatments. At 120 DAI, the maximum reduction of disease incidence of 100% was found under treatments T. harzianum + Provax 200 and T. harzianum + Score 250 EC, which were followed by Soil amendment with Poultry manure +Score 250 EC , Poultry manure + Garlic clove extract, Soil amendment with vermicompost + Provax 200, Vermicompost + Score 250 EC, Vermicompost + Pencozeb 80 WP, Soil amendment with Trichoderma harzianum + Tilt 250 EC and T. harzianum + Garlic clove extract showing 91.67% disease reduction of disease incidence. The highest number of leaf (20.25/plant), weight of leaf (105.25 g/pant) and leaf yield (8.25 t/ha) were obtained with the treatment T. harzianum

+ Provax 200. The second highest leaf number, leaf weight and leaf yield of 18.75/plant, 97.68g/plant and 81.25 t/ha, respectively were obtained with the treatments with Vermicompost + Provax 200 and Vermicompost + Score 250 EC. All treatments with IPM components increased leaf yield by 55.63-82.78% over control. Based on findings of the experiment it was noted that the maximum reduction of disease incidence of 100% was recorded from treatments Soil amendment with Trichoderma harzianum + Provax 200 and Soil amendment with Trichoderma harzianum + Score 250 EC, which were followed by Soil amendment with Poultry manure + Score 250 EC,

Soil amendment with Poultry manure + Garlic clove extract, Soil amendment with vermi-compost + Provax 200, Soil amendment with vermi-compost + Score 250 EC, Soil amendment with vermicompost + Pencozeb 80 WP, Soil amendment with T. harzianum + Tilt 250 EC and Soil amendment with T. harzianum + Garlic clove extract where reduction of disease incidence was 91.67%. As a conclusion it may be mentioned that as integrated approach application of either Provax 200 (0.2%) or Score 250 EC (0.1%) or Garlic clove extract (1:2 w/w) in combination with soil application of Trichoderma harzianum or Vermicompost was found as the suitable approach for the management of foot and root rot disease of betelvine that reduced up to 100% disease incidence increasing yield upto 82.78% over control.