Summary Efficiency of various organic acids, organic salts, essential oils, algae (an extract of Chlorella vulgaris and a commercial product), and bioagents against Magnaporthiopsis maydis, causing maize late wilt disease, was evaluated in laboratory and field conditions. For the in vitro tests, isolated M. maydis field strains from Egypt were used. Additionally, in field experiments different application methods were tested for their efficacy throughout two successive growing seasons. Results showed maximum growth inhibition of M. maydis at different concentrations of salicylic acid, ascorbic acid, benzoic acid and humic acid as well as sodium benzoate, potassium sorbate, di-potassim phosphate and calcium choloride, in descending order. The essential oils of carnation, lemongrass and black seed followed a similar trend. The minimum pathogenic fungal growth was achieved when the pathogen was exposed to the antagonistic Trichoderma viride followed by Trichoderma harzianum, Bacillus subtilis and Pseudomonas fluorescens treatments. Under field conditions, the highest disease reduction was recorded after treatment with salicylic acid (all application methods), humic acid (all application methods), sodium benzoate (seed dressing), carnation oil (seed dressing or seed dressing +foliar spray) and the bioagents B. subtilis and P. fluorescens (soil drench). Overall, all treatments and all application methods led to significant lower disease incidence compared to the untreated control in both growing seasons. Additionally, all treatments achieved an enhancement of plant morpho-genesis and yield characters. The most effective combinations of compounds/bioagents and application methods can be considered for future use in IPM management of late wilt disease of maize.

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Background Stem rust caused by Puccinia triticina Erikss is one of the most devastating fungal foliar diseases, and causes substantial yield losses to wheat crops cultivated under field conditions. This study aimed to evaluate the efficacy of plant extract-based foliar sprays for wheat with carnation, ginger and cinnamon on the severity of stem rust infection of three wheat cultivars cultivated under field conditions for two consecutive winter seasons of (2020/21 and 2021/22). Results In both seasons our data showed that all treatments were associated with some degree of disease suppression recorded as a range of 2.3–8.6% compared to 15.3–24.5% in untreated control treatment. The plant extract treatment was more effective than Amistar, a commercial fungicide. They recorded disease severity as: scores ranged between 2.3 and 3.2%; 3.0–4.5%, and 3.0–6% for wheat cvs. Giza 1, Misr 2, and Sids 14, in respective order. Meanwhile, scores of 4.1, 7.5, and 8.6% were recorded at fungicidal treatment. Spaying wheat plants with carnation extract showed the lowest disease prevalence followed by ginger and cinnamon extract, respectively. Increased in grain yield was associated with reduced disease severity. Conclusions The present investigation demonstrated the efficacy using plant extracts against foliar diseases caused by Puccinia and it was suggested that they may be an alternative to traditional chemical treatment.

Background and Objective: Pea (Pisum sativum L.) was attacked by many foliar diseases. Downy mildew, powdery mildew and rust are the most common diseases that affect the quantity and quality of this crop. To control these diseases, certain natural organic acids, e.g., citric, benzoic, salicylic, boric, sorbic acids and also coumarin were foliar sprayed to examine the possibility of avoiding the adverse effect of biotic stress. Materials and Methods: The experiment was conducted at Kafr-El-Dwar district, Beheira Governorate, Egypt during 2 successive summer seasons of 2019 and 2020 to evaluate pea plants foliar spray with some organic acids and coumarin at the rate of 0.25 and 0.50% against some foliar diseases. Results: The results proved that citric and benzoic acids at 0.50% induced the highest reduction of downy, powdery mildew and rust, while coumarin recorded the lowest reduction at the same concentration and other tested materials came moderately. Moreover, all tested substances gave clear increases in crop parameters and alleviated the harmful effects of biotic (diseases) stress. Acceleration in the recovery in terms of enhancing photosynthetic pigments, indole acetic acid, phenolic, some compatible solutes and antioxidant content was recorded. Also, a positive variation in anatomical structure, e.g., the leaflet blade thickness, upper and lower epidermal layers, vascular bundles, midrib zone, palisade and spongy tissues was noticed. Conclusion: Conclusively, foliar spraying with tested materials alleviated the harmful effects of biotic stress and accelerated the recovery and improved pea plants productivity.

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