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Witches'
Broom Disease of Lime
Witches' Broom Disease of Lime (WBDL) was first observed in
Sultanate of Oman in 1974 (12) and it is caused by Candidatus
Phytomplasma aurantifolia (13). The disease is well-established
and wide spread in all regions of Oman. It was first recorded
in United Arab Emirates in 1989 (6), Iran along Pakistan border
in 1997 (10) and India in 1999 (7). However, Bové et al.
(4), feel the disease recorded in India is Multiple Sprouting
and not Candidatus Phytoplasma aurantifolia since no
serological and/or molecular assays with WBDL phytoplasma
is established.
- A -
Early stage
infection by Witches Broom Disease caused by Candidatus
Phytoplasma aurantifolia
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- B -
Intermediate
stage infection
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- C -
Advanced stage
infection
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- D -
A healthy
plant
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The disease is characterized by the development of witches'
brooms on affected lime trees, which includes small new pale
green leaves produced as a bushy like appearance and a clump
of shoots. In the early stage, there will be a small number
of these witches' brooms. However, in the advanced stages,
the leaves of the older witches' brooms die, but will be attached
to the tree for some time and as the disease progresses, those
leaves will dry up and eventually fall off leaving behind
dead twigs, shoots and dried witches' broom. At this stage,
the tree is almost dead and unproductive. However, the infected
trees will carry very few small fruits, which will die quickly.
The period from the first witches' broom to the last stage
takes about five to six years (1, 2, 3, 5, 8).
The natural host range of WBDL includes Citrus aurantifolia,
C. medica, C. limetta, C. lemon and C. jambhiri.
In United Arab Emirates, sweet lime (Citrus limettioides)
was recorded to be infected naturally by WBDL (11). However,
it was not seen naturally infected by WBDL in Oman (8,9)).
Among non-rutaceous plant hosts, periwinkle (Catharanthus
roseus) was found to be infected naturally (1, 9). Three
weeds hosts were identified as natural hosts for WBDL based
on symptomology and ELISA; Achyranthes aspera, Amaranthus
graecizans and Suaeda fruticosa (9).
Talal S. Al-Zadjali, Phd candidate, Entomology, Insect Vectors
of Plant Pathogens,P.O. Box 2512, P.C.111, CPO, Muscat, Sultanate
of Oman, Tel: 00968 99226577, Email: abu.a.464@gmail.com
References
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1.
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Al-Zadjali, A.D. 1996. Ultra-structural,
histological, DNA diagnostics and tissue culture studies
on Witches' broom disease of lime. MSc thesis, Biological
science Dept., Wye College, University of London. |
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2.
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Bové, J.M. 1986. Witches' broom
disease of lime. FAO Plant Protection Bulletin, 34(4):
217-218. |
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3.
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Bové, J.M. 1995. Virus and virus
like diseases of citrus in the Near East region. Food
and Agriculture Organization of the United Nations (FAO). |
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4.
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Bové, J.M., L. Danet, K. Bananej, N.
Hassanzadeh, M. Taghizadeh, M. Salehi and M. Garnier.
2000. Witches' broom disease of lime (WBDL) in Iran.
Fourteenth IOCV Conference, Pages 207-212. |
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5.
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Bové, J.M., M. Garnier, A.M. Mjeni
and A. Khayrallah. 1988. Witches' broom disease
of small-fruited acid lime trees in Oman: First MLO
disease of Citrus. Pages 307-309. In: Proceedings of
the 10th Conference of the International Organization
of Citrus Virologists (IOCV), Riverside. |
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6.
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Garnier, M., L. Zreik and J.M. Bové.
1991. Witches' broom, a lethal mycoplasmal disease of
lime trees in the Sultanate of Oman and the United Arab
Emirates. Plant Disease, 75:546-551. |
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7.
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Ghosh, D.K., A.K. Das, S. Shayam, S.J.
Singh, Y.S. Ahlawat and S. Singh. 1999. Occurrence
of witches' broom, a new phytoplasma disease of acid
lime (Citrus aurantiifolia) in India. Plant Disease,
83 (3): 302. |
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8.
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Moghal, S., P. Shivanathan, A. Mani,
A.D. Al-Zadjali, T.S. Al-Zadjali and Y.M. Al-Raeesy.
1993. Plant Diseases in the Batinah. Mazoon Printing
Press, Directorate General of Agricultural Research,
Rumais, Sultanate of Oman. Document No. 6/93/22. |
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9.
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Moghal, S.M., A.D. Zidgali and S.S.
Moustafa. 1998. Natural host range and reactions
of citrus species to witches' broom disease of lime
(WBDL) in Oman. Pages 143-152. In Proceedings of the
IPM Conference, Sultan Qaboos Univ., Muscat. |
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10.
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Salehi, M., K. Izadpanah and H. Rahimian.
1997. Witches' broom disease of lime in Sistan, Baluchistan.
Iranian Journal of Plant Pathology, 33: 3-4, 76. |
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11.
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Shereqi, R.K. and S. Gassouma.
1993. Witches' broom disease in United Arab Emirates.
Pages 453-454. In: Proceedings of the 12th Conference
of the International Organization of Citrus Virologists
(IOCV), Riverside. |
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12.
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Waller, J.H. and J. Bridge. 1978.
Plant diseases and nematodes in the Sultanate of Oman.
Ministry of Agriculture and Fisheries. 8 pp. |
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13.
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Zreik, L., P. Carle, J.M.
Bové and M. Garnier. 1995. Characterization of the
Mycoplasma like Organism Associated with Witches'-Broom
Disease of Lime and Proposition of a Candidatus Taxon
for the Organism, ''Candidatus Phytoplasma aurantifolia".
International Journal of Systematic Bacteriology, 45(3):
449-453. |
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