Document Type : Original Article
Authors
1
Plant Pathology Research Institute, Agricultural Research Center, 12619, Giza, Egypt.
2
Plant Pathology Research Institute ARC
3
Plant Pathology Department, Faculty of Agriculture, Ain Shams University P.O. Box: 68, Hadayek Shobra 11241, Cairo, Egypt.
Abstract
Early fruit drop is one of the most important diseases that usually decrease the production of mango trees in Egypt. The typical symptoms of early fruit drop were observed on four surveyed Egyptian mango cultivars (Hindy, Ewais, Keitt, and Montakhab El-Qanater) during 2022 and 2023 seasons. Among these cultivars, Montakhab El-Qanater recorded the highest percentage of fruit drop while Ewais showed the lowest percentage in both inspected seasons. Fusarium moniliforme Sh., Lasiodiplodia theobromae Pat. and Alternaria alternata (Fr.)Keissler, were isolated from early dropped fruits of inspected cultivars and recorded the highest frequencies, respectively. Pathogenicity test showed that isolated fungi were able to induce the early fruit drop disease with typical symptoms. Montakhab El-Qanater cv. was the most susceptible for fungal infection compared to Ewais cv. Infection with each of F. moniliforme, and L. theobromae was inherent to the high percentage of fruit drop compared with A. alternata. In vitro, the efficacy of five commercial agrochemical products (Bellis, Craft, Dovex, Score and Tekto) was evaluated on the isolated fungi. Generally, the linear growth of any of the isolated fungi was inhibited with 0.5ml/L of Score, 0.5g/L of Bellis and 1ml/L of Tekto, respectively. In vivo, the treatment with Score (50ml/100L) significantly decreased early fruit drop during the two experimental seasons on Montakhab El-Qanater and Ewais cultivars. The lowest efficacy was obtained with Craft (40ml/100L) and Dovex (25ml/100L). The physiological effects of the evaluated products were measured on total phenolic content and enzymatic activities of chitinase (CHT), peroxidase (PO) and polyphenol oxidase (PPO) in leave extract of Montakhab El-Qanater and Ewais cultivars. The total phenolic content and enzymatic activities were significantly promoted in both cultivars with the treatments of the evaluated chemicals. The highest values of total phenolic content in both cultivars were detected with Score, Bellis and Tekto, respectively. While, the greatest activity of measured enzymes was revealed with Bellis, Score and Tekto, respectively.
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