Articles
Identification and pathogenicity of Botryosphaeria species associated with mango dieback disease in Egypt and Israel
Article number
1415_31
Pages
257 – 264
Language
English
Abstract
Fungal diseases including dieback and fruit stem end rot, caused by Botryosphaeriaceae genera, were recently recorded from multiple locations in Egypt and Israel.
During 2022, approximately 40% of mango trees showing symptoms of twig and branch dieback, leaf necrosis, leaf fall, internal stem necrosis, and darkening within the vascular tissue, were detected from 45 farms located in Sharkya, Ismailia and Behera Governorates in Egypt, and from six mango orchards across Israel.
Sections from diseased branches were plated on PDA at 25°C and after 3-5 days, cultures containing grayish-white to dark-gray to black mycelia were observed.
After 21 days, the colonies produced dense aerial mycelia with dark-colored pycnidia and conidia.
In Egypt, morphological characteristics were consistent with Lasiodiplodia theobromae, L. pseudotheobromae, and Neoscytalidium dimidiatum. Similarly, in Israel, L. theobromae, and N. dimidiatum were identified as causal agents of mango stem and inflorescence dieback based on morphology and molecular phylogeny.
In Egypt and Israel, pathogenicity tests of selected isolates were carried out on healthy two-year-old mango cultivar ‘Eweis’ and ‘Shelly’ seedlings, respectively, by inoculating wounded apical buds with the representative isolates and water controls.
All seedlings, five replicate plants per treatment, were kept under greenhouse conditions (27°C, 16/8-h day/night; 70% relative humidity) and monitored for disease development.
After 28 days, all inoculated plants displayed similar symptoms to those observed in the field, whereas control plants remained healthy.
Koch’s postulates were fulfilled when typical colonies of L. theobromae, L. psedotheobromae and Neoscytalidium dimidiatum were successfully re-isolated from symptomatic tissues.
The identification of Botryosphaeriaceae fungi is important to establish suitable control measures and quarantine requirements.
During 2022, approximately 40% of mango trees showing symptoms of twig and branch dieback, leaf necrosis, leaf fall, internal stem necrosis, and darkening within the vascular tissue, were detected from 45 farms located in Sharkya, Ismailia and Behera Governorates in Egypt, and from six mango orchards across Israel.
Sections from diseased branches were plated on PDA at 25°C and after 3-5 days, cultures containing grayish-white to dark-gray to black mycelia were observed.
After 21 days, the colonies produced dense aerial mycelia with dark-colored pycnidia and conidia.
In Egypt, morphological characteristics were consistent with Lasiodiplodia theobromae, L. pseudotheobromae, and Neoscytalidium dimidiatum. Similarly, in Israel, L. theobromae, and N. dimidiatum were identified as causal agents of mango stem and inflorescence dieback based on morphology and molecular phylogeny.
In Egypt and Israel, pathogenicity tests of selected isolates were carried out on healthy two-year-old mango cultivar ‘Eweis’ and ‘Shelly’ seedlings, respectively, by inoculating wounded apical buds with the representative isolates and water controls.
All seedlings, five replicate plants per treatment, were kept under greenhouse conditions (27°C, 16/8-h day/night; 70% relative humidity) and monitored for disease development.
After 28 days, all inoculated plants displayed similar symptoms to those observed in the field, whereas control plants remained healthy.
Koch’s postulates were fulfilled when typical colonies of L. theobromae, L. psedotheobromae and Neoscytalidium dimidiatum were successfully re-isolated from symptomatic tissues.
The identification of Botryosphaeriaceae fungi is important to establish suitable control measures and quarantine requirements.
Publication
Authors
S.A. Youssef, A.A. Shalaby, W.H. Abd El-Monem, K.M. Abd El-Ghany, G. Sharma, M. Elazar, M. Maymon, S. Suaza-Blandon, V. Meshram, D. Ezra, N. Alkan, S. Freeman
Keywords
Botryosphaeriaceae, disease diagnosis, fungal disease, molecular phylogeny, plant disease
Groups involved
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