Study on the effect of yeast in compost tea efficiency in controlling chocolate leaf spot disease in broad bean (Vicia faba)

Abstract

This study was conducted to determine the effect of adding yeast to compost tea in the biocontrol activity of compost tea against chocolate leaf spot disease in broad bean as a proposed biocontrol treatment, in addition to effects on soil biota, yield, and growth parameters of broad bean. Faba bean was planted in plastic bags filled with 11 kg of non-sterilized clay soil. Foliar compost tea–yeast mixture was applied 40 days post-sowing and 1 day pre-inoculation with Botrytis fabae spore suspension. Soil drenching was done directly, before seeds sowing, at a rate of 100 ml/bag. Seed treatment was done for 24 h before seeding. The trial was designed in complete randomized block design with three triplicates for each treatment. Adding yeast to compost tea as seed soaking treatment significantly decreased the disease severity when integrated with foliar spray and soil drenching. Foliar and seed soaking treatments significantly increased pod number, seed weight, and population of soil microorganisms. Foliar treatment increased peroxidase enzyme content. Seed soaking treatment increased polyphenol oxidase enzyme level. Total phenol content increased with foliar spray, seed soaking, and soil drenching when compared with control. It can be concluded that adding of the yeast to compost tea in seed soaking treatment resulted into biocontrol of chocolate leaf spot disease of broad bean, increased soil microorganism population, pod number, seed weight, polyphenol oxidase enzyme, and total phenolic contents.