Plant Health Plant Diseases and Pests and their Management
مفالات متعلقه
First report of neck rot diseases of date palm caused by Chalara paradoxa in Saudi Arabia .
Mohamed A. El-Meleigi
Plant Production and Protection Department, College of Agriculture and Veterinary Medicine, Qassim University, Burydah, Saudi Arabia. meleigi@hotmail.com
Cold stressed date palm ( Phoenix dactylifera L.) trees were severely infected with Chalara paradoxa leading to neck rot and bending of stem. Over four thousands mature date palm trees ( 15- 20 years old) were killed by the disease. Barhee variety was the most affected by the disease (82%) , while 5-20% of the other varieties including Succary , Khalas, and Wannana were killed by the disease. The appearance of diseases symptoms was preceded by out break of leaf spots and dieback of leaves caused by Alternaria alternate. Leaves of affected palms were severely spotted and dried prior to the occurrence of neck bending and stem collapses. The fungus Chalara paradoxa was readily isolated from leaves, stems and roots of all affected trees on homemade acidified Potato Dextrose Agar (APDA). C. paradoxa is known to be a soilborne and causes black scorch diseases of date palms in Saudi Arabia (Al-Rokibah et al. 1998 & Molan et al. 2004), but rarely seen to cause neck rot and bending of the stems. Severely affected date palm farms in Qassim region, Central Saudi Arabia were exposed to -10 C for two consecutive nights during January. Although, C. paradoxa was reported as an opportunist the affect salt stressed trees ( Al-Rokibah et al. 1998 & Suleman et al. 2001 b). This is the first report on the effect of cold stress on promoting neck rot of date palm.. Neck pending disease of date palm caused by C. paradoxa was previously reported in Iraq (Abbas et al. 1992), in Qatar (Abbas and Abdullah 2003) and in Kuwait (Suleman et al. 2001 a).
References
Abbas, E.H. and A.S. Abdulla, 2003. First report of neck banding disease on date palm in Qatar. Plant Pathol., 52: 790-790.
Al-Rokibah, A.A., M.Y. Abdalla and Y.M. El-Fakharani, 1998. Effect of water salinity on Thielaviopsis paradoxa and growth of date palm seedlings. J. King Saud Univ. Agric. Sci., 10: 55-63.
Molan, Y.Y., R.S. Al-Obeed, M.M. Harhash and S. El-Husseini, 2004. Decline of data palm offshoots infected with chalara paradoxa in Riyadh region. J. King Saud Univ., 16: 79-86.ase Reports 7, 12.
Suleman P, Al-Musallam A, Menezes CA, 2001a. Incidence and severity of black scorch on date palms in Kuwait. Kuwait Journal of Science and Engineering 28, 161-170.
Suleman P, Al-Musallam A, Menezes CA, 2001b. The effect of solute potential and water stress on black scorch caused by Chalara paradoxa and Chalara radiciola on date palms. Plant Disease 85, 80-83.
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