Fusarium Wilt on Pepper, Disease Incidence and Control Potential using Trichoderma Longibrachiatum

Abstract

Fusarium wilt is one of the important and major diseases that affect pepper crops in different parts of the world. The study aimed to determine the presence of wilt fungi associated with pepper crops in different areas of central Iraq and to evaluate the response of different pepper varieties to infection with the possibility of reducing infection using the biological agent Trichoderma longibrachiatum. The results of a survey of 10 areas showed the presence of Fusarium spp. on pepper in six areas covered by the survey. The fungal isolates were purified and multiplied and their pathogenicity was tested, where two isolates with the highest pathogenicity and an isolate with medium pathogenicity were selected for field tests. The pathogenic isolates were diagnosed microscopically and morphologically, and the diagnosis was confirmed molecularly, which was found to be due to the fungus Fusarium solani and registered under the accession number (PP95237) in (NCBI). The antagonism of the biological fungus Trichoderma longibrachiatum registered under the accession number MZ021580 against the isolated fungi was tested. The results showed the highest percentage of antagonism against the isolate (F3), while the antagonism ranged from (82.35) to (83.88). The pathogenicity of the pepper plant was tested for the three hybrids Carisma, Gennext and Golden Land, as the isolates F3 and F5 of the fungus Fusarium spp. gave the highest percentage of seed rot and seedling death. To evaluate the effectiveness of the biological control agents and varieties used to control Fusarium wilt disease on pepper, the results showed that T. longibrachiatum led to a reduction in the disease severity. T. longibrachiatum was superior in the field in increasing plant height, leaf area, dry weight of vegetative and root groups, fruit weight, total yield regardless the pepper variety compared to pathogen infected and in the absence of biological factor. Golden Land was superior in the field in most of the study indicators, especially in the presence of the biological fungus T. longibrachiatum.