Thyme (Thymus vulgaris L.) Root Rot/Wilt in Minia Governorate, Egypt

Abstract

Thyme (Thymus vulgaris L.) is a medicine and aromatic plant, have a great economic important due to the great income that it provides and other diversified usages. Damping-off, root rot and wilt symptoms were observed in field thyme grown in Maghagha and Beni Mazar districts, Minia Governorate, Egypt, during November to March, 2016-2017. Survey, sampling and pathogenicity tests were carried out. Fusarium semitectum, F. solani, Rhizoctonia solani and Macrophomina phaseolina were the dominant pathogens causing thyme damping off, root rot and wilt. The inhibitory effect of two resistance inducer substances (salicylic and ascorbic acids) three fungicides (Cure M 72% WP, Rizolex Ex-T 50% WP and Rolex 50% WP) on the growth of the most pathogenic fungi in vitro was investigated. Salicylic acid inhibited the growth of F. semitectum and R. solani completely at 200ppm but the growth of M. phaseolina was completely inhibited at 400ppm. The complete inhibition for the growth of all tested pathogens was occurred at 400 ppm Ascorbic acid. F. semitectum and R. solani were more sensitive to Rizolex T, while M. phaseolina was more sensitive to Cure-M, (causing the lowest diameter averages The results of the present investigation showed the possibility to use certain antioxidants as fungicides alternatives to control plant pathogenic fungi. According to the available literature, this is a first study on thyme root rot/wilt in Egypt.