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The nematicidal potential of five filamentous fungi as biological control agents (BCAs) against the root-knot nematode (RKN), Meloidogyne javanica, infecting tomato was assessed in vitro and in pot experiments. The five promising native taxa, namely Trichoderma longibrachiatum, T. harzainum, T. asperellum, Lecanicillium spp., and Metacordyceps chlamydosporia, were selected to compare their effectiveness against both chemical (Mocap, 10% ethoprophos) and biological (abamectin) nematicides on M. javanica reproduction indices and plant growth parameters. The stimulation of defense mechanisms was assessed by monitoring changes in the enzymatic activities of the polyphenol oxidase (PPO), peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), lipid peroxidation (MDA), phenols, and proteins content of tomato roots. The laboratory assays revealed that T. longibrachiatum, M. chlamydoporia, and Lecanicillium spp. seemed to be the most effective under laboratory conditions, with more than 60% of juvenile mortality. The egg infection rate was above 62%, and the egg hatching rate was below 32%. The direct parasitism by the five taxa was confirmed by scanning electron microscope observation. The results of this study found a similar parasitism mechanism for T. longibrachiatum, T. harzianum, and M. chlamydosporia, where their hyphae and spores adhered to the M. javanica juveniles cuticle layer and formed trapping rings around them. The pot experiment results showed that T. harzianum and Lecanicillium spp. enhanced the plant growth parameters. Trichoderma longibrachiatum, abamectin, and the ethoprophos-based nematicides effectively decreased the reproduction rates of the nematode. The Trichoderma species and M. chlamydosporia significantly reduced the gall index and female fecundity of RKN. The treatment with BCAs and chemical nematicides involved a significant increase in the antioxidant activities of nematode-infected plants. The ethoprophos and fungal treatments decreased the MDA and total phenols content compared with the nematode-infested seedlings. This paper analyzes the advancements made towards the effective and efficient biocontrol of M. javanica using different fungal taxa, especially T. longibrachiatum and M. chlamydosporia, and the implications of these advancements for sustainable agriculture and food security. [ABSTRACT FROM AUTHOR]

Alternaria alternata, responsible for Alternaria leaf spot, is spread worldwide, notably in Iraq. This disease is characterized by lesion formation on the leaves, leading to substantial yield and quality losses in several plant species such as Cucumis melo (melon). Glomus mosseae and Trichoderma harzianum are considered eco-friendly and bio-safe alternatives to traditional chemical fungicides due to their intrinsic ability to induce native anti-stress pathways in plants. This research study was conducted to evaluate the efficacy of the tested bio-agents, G. mosseae and T. harzianum (in combination or separately), on cucumber infected with A. alternata under greenhouse conditions. G. mosseae and T. harzianum provided strong inhibitory effects against leaf spot disease, decreasing disease severity index (DSI = 31.35 and 40.39%, respectively) and disease index (DI = 1.30 and 1.49, respectively). Obtained results revealed that the separate treatment of melon against this airborne pathogen using G. mosseae and T. harzianum generated the strongest activity of catalase (CAT = 5.678 and 3.389 units/mg protein/min, respectively) and peroxidase (POX = 9.948 and 7.542 units/g/ml/min, respectively). However, the ongoing results revealed that the combination of G. mosseae and T. harzianum negligibly reduced DSI (47.04%) and DI (2.08) and increased CAT (1.962 units/mg protein/min) and POX (3.08 units/g/ml/min) activities. To control A. alternata within integrated pest management strategies, biological control agents (such as G. mosseae and T. harzianum) should be considered. [ABSTRACT FROM AUTHOR]

Alternaria solani responsible for early blight of eggplant is a worldwide spread notably in Iraq. The use of biological control agents represents the best alternative and eco-friendly approach. Two soil-borne fungal (Paecilomyces lilacinus and Trichoderma harzianum) were tested in laboratory conditions using the dual confrontation technique at different concentrations of conidia filtrate (10, 20 and 30% conidia/mL) and in vivo as potential bio-agents against A. solani. T. harzianum possessed the highest antifungal potency against A. solani with an inhibition rate above 50% at a concentration of 30% conidia/mL. In greenhouse experiments, both P. lilacinus and T. harzianum treated preventively on eggplant leaves inoculated with A. solani lowered significantly the disease severity index (31.61% and 28.08%, respectively). Obtained results revealed an augmentation of the peroxidase activity (4.84 units/g/mL/min for P. lilacinus; 3.88 units/g/mL/min for T. harzianum) in comparison with positive and negative controls. The effect of these two antagonists is limited not only to the protection of eggplant plants but also to the improvement of their growth by increasing the fresh (27.01% for P. lilacinus and 34.45% for T. harzianum) and dry weights (3.31% for P. lilacinus and 5.90% for T. harzianum) of the above-ground portion. Based on our results, we can conclude that T. harzianum could be recommended for biological control use. [ABSTRACT FROM AUTHOR]