Due to the various negative impacts of chemical fungicides, the reduction of its applications in agricultural production process is widely recommended. Thus, the need and application of bio-agents in disease control has increased tremendously. The current study aimed at investigating the role of both bio-agents Glomus mosseae (mycorrhizal fungi) and Trichoderma harzianum in protection of Cucumis sativus (cucumber plants) against the fungal pathogen Alternaria alternata which is an opportunistic pathogen and the causal agent of cucumber wilt disease. Results obtained from this work revealed the positive influence of using bio-agents treatments in the reduction of pathogenic effects of A. alternata. The results also showed that G. mosseae and T. harzianum combination had a positive synergistic influence in reducing the detrimental effects of A. alternata ny improving the biomass yield (e.g. fresh and dry weight of root); as well as, on disease severity on C. sativus. Bio-agents (G. mosseae and T. harzianum) increased resistance in C. sativus by raising the production of enzymes catalase and peroxidase. Conclusively, this research revealed that using a multifarious combination of bio-agents significantly (P =.05) increased the efficiency of biological control of A. alternata than using each of them exclusively. Thus, it is recommended that to get an effective result in the control of the pathogen A. alternata in crops as highlighted by the results of this work; a combination of two bio-agents should be used.

Mycorrhizae establish symbiotic relationships with plants and play an essential role in plant growth, disease protection, and overall soil quality. There are two main categories of Mycorrhizae relationships: Endomycorrhizal fungi (Arbuscular Mycorrhizal Fungi) (AMF) form relationships with over 90% of plants (including turf grasses). Ectomycorrhizae fungi form relationships with only about 2% of plants, but some of them are quite common. In this scientific review, we will only talk about Endomycorrhizal. Mycorrhizae described in current scientific literature, the Endomycorrhizal the most abundant and widespread. The molecular basis of nutrient exchange between Arbuscular Mycorrhizal (AM) fungi and host plants is presented. The role of AM fungi in disease protection, Root colonisation by Arbuscular Mycorrhizal Fungi (AMF) can improve plant resistance/tolerance to biotic stresses. Although this bio protection has been amply described in different plant systems, the underlying mechanisms remain largely unknown. Besides mechanisms such as improved plant nutrition and competition, experimental evidence supports the involvement of plant defense mechanisms in the observed protection. During mycorrhiza establishment, modulation of plant defenses responses occurs upon recognition of the AMF in order to achieve a functional symbiosis. As a consequence of this modulation, a mild, but effective activation of the plant immune responses may occur, not only locally but also systemically. This activation leads to a primed state of the plant that allows a more efficient activation of defense mechanisms in response to attack by potential enemies.

Grapevine is an important fruit crop grown in the Chott Sidi Abdel Salam oasis in south eastern Tunisia. It provides great economic potential for the oasis population due to its higher yield and monetary returns. It, also, has a good nutritional value and is consumed fresh or in dried form. Powdery mildew represents one of the most destructive diseases affecting viticulture, especially in temperate-humid climate. It is an economically important fungal disease in the grapevine farms. This pathogen is able to differentially attack leaves and grapes, and is currently controlled with repeated applications of fungicides. This research aimed to use chemical control in order to assess the ability of contact, systemic and the combination of both routes of fungicides’ administration, at three different sampling moments to manage powdery mildew infestation of grapevines (Cv. Bazzoul Kalba), under field conditions. The experiments were conducted in the oasis of Chott Sidi Abdel Salam in southeastern Tunisia. Both Pristine WG and Vectra 10 SC allowed controlling the disease intensity of powdery mildew compared to Talendo® showing a highly significant augmentation of the inhibitory growth potential (84.26% and 88.94%, respectively at 21 days after the first fungicide application) and the protective potential (73.11% and 76.92%, respectively at 21 day). This information can be used to help grapevines growers to improve powdery mildew control and enhance marketable yields.

Recently, a wide range of symptoms including light yellow lesions gradually turning into brown stripes were noticed on date palm leaves in Iraq. In this context, the aim of this study were to isolate the phytopathogens associated with these symptoms, evaluate their pathogenicity and assess the efficacy of two fungicides (Score and Pentanol) under in vitro and in vivo conditions. Two fungal species (Alternaria sp. and Fusarium sp.) were isolated from the symptomatic leaves of date palm. The results of pathogenicity tested proved the ability of Alternaria sp. inoculated separately or in combination with Fusarium sp. to infect the leaves of date palm trees with disease severity index (DSI) values of 67.33% and 65.99%, respectively. The effect of Score (88.76%) and Pentanol (82.91%) against Alternaria sp. was examined by poisoned food technique, which leads a significant increase in mycelial growth inhibition (for 300% of commercial recommended dose of fungicide). Test results indicate that prophylactic spraying of date palm leaves with Score or Pentanol effectively controlled Alternaria sp. with DSI values of 22.65% and 17.87%, respectively. To control Alternaria sp. in field within integrated pest management strategies, chemical control using Score or Pentanol should be taken in consideration.

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