Inhibitory effect of some plant extracts and Trichoderma spp. on growth of Fusarium oxysporum causing wilt of pepper (Capsicum annuum L.)

Fusarium wilt, a disease induced by Fusarium oxysporum f.sp. capsici, has a substantial impact on the growth of peppers in the Menoufia governorate area of Egypt. Lost production is the consequence of this illness. The efficacy of four aqueous plant extracts was evaluated in greenhouse and laboratory environments to manage the Fusarium wilt pathogen.The extract of Laurus nobilis, Dianthus caryophyllus, Cinnamomum verum, and Azadirachta indica demonstrated a significant reduction in the growth of mycelia in the F. oxysporum isolate in in vitro trials.Carnation aqueous extract were the most effective one against Fusarium. The data obtained indicated that the pathogenic fungal growth was completely suppressed at concentrations of 2.5, 5, and 10% of Dianthus caryophyllus extract. Trichoderma harizianum inhibited the mycelia growth by 93.38% ,followed by T. Viride with 89.27%. InThe most effective treatment against Fusarium was the carnation aqueous extract.The data obtained indicated that the pathogenic fungal growth was completely suppressed at concentrations of 2.5, 5, and 10% of Dianthus caryophyllus extract. Trichoderma harizianum inhibited the proliferation of mycelia by 93.38%, while T. viride did so by 89.27%.Compared to the infected plants (positive control), all treatments were efficacious in reducing the incidence of wilt (post-emergence damping off and severity of infection) and increasing certain vegetative growth parameters of pepper plants (plant height and root weight) in spots experiments. The ultrastructural investigations of pepper plants that were treated with Dianthus caryophyllus extract revealed an increase in the size of plaside cells, spony cells, in comparison to the infected leaves, as well as the quantity of xylem arms and phloem layers.