In Vitro Management of Foot and Root Rot of Betel Vine (Piper Betie L.) Incited By Sclerotium Rolfsii

Abstract

Betel vine (Piper betle L.) is largely grown as an important cash crop throughout the tropical and subtropical regions in Bangladesh. Disease damage to the crop is one of several known limiting factors. Foot and root rot of betel vine caused by Sclerotium rolfšii is the most overwhelming disease which decreases the production of betel leaf to a great extent. The present study was catTied out in the Plant Protection Laboratory of Agrotechnology Discipline, Khulna University, Khulna to evaluate in vitro the efficacy of different fungicides, botanicals, antagonist microorganisms and organic amendments against Sclerotium rolfšii. To fulfill the objectives four fungicides, four plant extracts/botanicals, two bioagents and four organic amendments at different concentration was considered against Sclerotium rolfsii, causal agent of foot and root rot disease of betel vine. The experiment was laid out in Completely Randomized Design (CRD) with four replications. Radial growth and formation of sclerotia were recorded. Radial growth inhibition was calculated thereafter. In all the cases, the growth inhibition was found to be increased with the increase of concentration against Sclerotium ro(fsii. Four fungicides viz., Unisaaf 75WP, Dithane M-45, Exzole 50 SC and Provax-200 at different concentrations (100, 150, 200, 250 and 500 ppm), were tested. Among the tested fungicides, Exzole 50 SC and Provax-200 showed complete growth inhibition of S. rolfsii at all the concentrations and consequently no sclerotia were formed. Four botanicals viz., Neem leaf, Tulsi leaf, Marigold leaf and Allamanda leaf extracts at different concentrations (10, 15, 20, 25 and 30%), were tested. Neem leaf extracts at 30% concentration showed highest percent inhibition (63.20%) and lower number of sclerotia formation (200.00) followed by tulsi leaf extract, marigold leaf and allamanda leaf extracts respectively. Two antagonist microorganisms T. harzianum and Bacillus subtilis strain (ATCC 6633) was evaluated against S. rolfsii. T. harzianum showed promising effect against mycelial growth inhibition (88.91%) of S. rolfsii and subsequently no sclerotia was formed. Secondary metabolites of Bacillus subtilis strain (ATCC 6633) was evaluated at different concentrations (1:2, and 1:6) against S rolfsii. Secondary metabolites at 1:6 concentrations showed highest percent of mycelial growth inhibition (89.54%) and consequently lowest number (34.00) of sclerotia was formed. Four organic amendments viz., Neem cake, Wood ash, Mustard cake and Coconut cake at different concentrations (10, 15, 20, 25 and 30%), were tested. All tested amendments at 30% concentrations showed highest percent inhibition and lower number of sclerotia formation.