Relative impact of vermiwash against phytophagous insects and growth properties of yardlong bean (<em>Vigna unguiculata</em>)

Abstract

Due to severe insect infestation, yardlong (Vigna unguiculata) bean expansion and production have been declining in Sri Lanka. This experiment tested the effectiveness of several vermiwash against phytophagous insects in yardlong bean. Ten distinct types of vermiwash were generated by alternately and separately feeding exotic (Eudriluseuginea) and indigenous types earthworm with the specified botanicals, viz. onion and garlic peel, marigold and neem leaves, and the materials given for mass culturing. Eleven treatments including 10 vermiwash and untreated control and three blocks were laid on Randomized Complete Block Design. Since the third week of planting, vermiwashes have been administered to the corresponding plots at weekly intervals. Before each application of treatment, the total number of insects in each treated and untreated plot were carefully counted. ANOVA assessed treatment effects, and Duncan's Multiple Range Test compared mean separation values at 5% significance using SAS software. Plots treated with vermiwash made from indigenous earthworm varieties with garlic peel (1.33), exotic varieties with onion peel (2.33), and native varieties with onion peel (3.00) had the significantly similar fewest epilachna beetles. Further, vermiwash of an indigenous variety with neem leaves, where the maximum yield of yardlong beans was also discovered, had a considerably lower population of epilachna beetles. Furthermore, with the exception of the vermiwash of exotic species with onion peel, practically all treatments were less harmful to ladybird beetles. As demonstrated by this experiment, vermiwash has a beneficial effect on plant development in terms of both plant height and leaf area. Vermiwash made from combining an indigenous species of earthworm with neem leaves was potentially suggested for yardlong bean production since it was both environmentally and economically efficient.