Symptomless Carriers of the Causal Agent of Tomato Wilt Pathogen

A study was carried out to determine whether naturally-occurring weeds and other cultivated plants in tomato growing regions could act as symptomless reservoirs of infection to Fusarium oxysporum f. sp. lycopersici. A numher of F. oxysporum isolates from weeds and oubergines were used in this investigation. A susceptible tomato cultivar was used for comparison. The plants were artificially inoculated at the five to six leaf stage by root dip method. Only tomato showed wilt symptoms and died three weeks after inoculation. These isolates were identified as F. o. f. sp. lycopersici. Weeds including Amaranthus retroflexus, Amaranthus. sp., Chenopodium album, and aubergines were colonized to various degrees and determined as symptomless carriers. Therefore, in infested areas, aubergines should not be rotated consecutively with tomatoes and proper measures should be adopted to control the weeds