Colletotrichum truncatum (syn. C. capsici), like many other members of the genus Colletotrichum, displays a highly developed infection mechanism against a number of agriculturally important crops. Among many survival strategies, C. truncatum is well known for its wide host range and high pathogenicity on several major crop species. Meticulous understanding of a pathogen's infection mechanisms is the best way to achieve successful management of a disease. This study was carried out to evaluate the pathogenicity of C. truncatum on selected crop plants and weed species and to detect the possibility of non-host species to facilitate survival of the pathogen. Inoculation of an isolate of C. truncatum to four crops: curry chilli -Capsicum annuum (var. CA8), eggplant -Solanum melongena (var. Lena Iri), tomato -Solanum lycopersicum (var. Thilina) and green chilli -C. annuum (var. KA2) and three weed species: little ironweed (Vernonia cinerea), billygoat-weed (Ageratum conyzoides) and Bengal dayflower (Commelina benghalensis) resulted in approximately 3.5 disease severity (DS) (100% disease incidence-DI) on S. lycopersicum and C. annuum (var. KA2), followed by 2.8 and 1.8 DS (100%, 75% DI) on C. annuum (var. CA8) and S. melongena (var. Lena Iri), respectively. The three weed species were completely symptomless up to 8 weeks after the inoculation (WAI). However, microscopic studies and serial culturing of the inoculated tissues revealed the presence of the fungus in all the tested plants. Appressoria were present in all treated leaves and eventually broke their dormancy upon leaf senescence nearly 6 WAI. This study reveals the potential of C. truncatum infecting all tested crops and the capability of the three weed species in harboring the pathogen asymptomatically for several weeks. Thus, early management of inoculum in the field is suggested for C. truncatum diseases.

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Wilt is one of the major diseases causing economic losses in many crops. It is caused by infections of many bacterial (Ralstonia solanacearum), fungal (Fusarium spp., Vertcillium spp., Rhizoctonia spp., Sclerotium spp.), oomycete (Pythium spp., Phytophthora spp.) and viral (Tomato spotted wilt virus) pathogens. This review provides an overview on the control strategies used in other countries for the wilt disease in highly susceptible vegetable/fruit crops; tomato and chilli and make comparisons with Sri Lanka. Many studies have been performed on the prevalence, severity, pathogenicity and the control of these infections in both crops worldwide. Wilt in tomato is caused mainly by Ralstonia solanacearum and Fusarium oxysporum and in chilli mainly by Fusarium oxysporum. Tomato bacterial wilt is successfully managed through usage of resistant cultivars, grafting, biological control agents, inducing host systemic resistance and integrated management. Tomato and chilli wilt caused by Fusarium sp. have been successfully controlled mainly through the application of chemicals and biological approaches such as systemic defense induction and the use of microbial antagonists. In Sri Lanka, tomato wilt is reported as being the result of bacterial, fungal and viral infections which have been mainly controlled by the usage of resistant cultivars, physical measures and cultural practices. Chilli wilt in Sri Lanka has not been thoroughly studied yet. But application of fungicides has been an effective strategy for fungal wilts. Wilt threat of tomato and chilli in Sri Lanka has to be further studied for the proper management of these infections and for freeing tomato and chilli cultivations from the wilt disease.