Wide spread occurrence of citrus greening in Bangladesh
Citrus greening (Huanglongbing; HLB) is one of emerging diseases of citrus in Bangladesh and has been known in East Asia for over a century. Symptoms include blotchy chlorosis and/or mottling of leaves; yellowish shoots; vein corking; stunted growth; poor root growth; small, green, and malformed fruits; and finally death of the plants.
The disease is caused by phloem-limited unculturalble bacteria, ‘Candidatus Liberibacter spp. (Ca. L.)’ and is transmitted by grafting and citrus psyllid Diaphorina citri. The presence of citrus greening (Huanglongbing) in Bangladesh was first reported in 2016 by Polymerase Chain Reaction (PCR) technique in only four districts viz. Khagrachari, Moulavibazar, Sylhet and Chittagong by Prof. Dr. Md. Rashidul Islam and his research team. After that in 2018, a comprehensive survey was conducted by Prof. Dr. Md. Rashidul Islam and his research team in some other districts viz. Panchagarh, Thakurgaon, Gaibandha, Mymensingh, Gazipur, Cumilla, Habigonj, Rangamati, Bandarban and Coxsbazar and his team confirmed the presence of Clas pathogen by PCR at Plant Bacteriology and Biotechnology Lab, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh.
Finally his research team concludes the wide spread prevalence of citrus greening (Huanglongbing) disease in total of 14 districts of the country at present. His research works were financed by University Grants Commission, Bangladesh and Ministry of Education, Bangladesh. Earlier he published a scientific article on the insect vector, Asian citrus Psyllid Bug (Diaphornia citri) in Pest Management Science journal in collaboration with the Huanglongbing Research laboratory at South China Agricultural University, Guangzhou, China. The research team concluded that Psyllid Bug (Diaphornia citri) from Bangladesh is lying close together genetically with Psyllid Bug (Diaphornia citri) from Southwest China and Bhutan.
Dr. Islam said, more research funding is needed to complete a wide spread survey covering the whole countries including several hosts such as Sweet orange (Malta), Mandarin (Kamola), Pummelo (Batabi lebu) and other plants of the family rutaceae specially murrya aimed to know the wide host range of citrus greening or HLB pathogen in the country. He further said that spread of the disease all over the country will be emerging as a threat for expansion of citrus cultivation specially Malta and Mandarin in the country.
He added, the execution of a national collaborative project on citrus greening (Huanglongbing), early detection of its pathogen, pathogen evolutionary analyses and integrated management approaches accelerate the government plan of increasing citrus fruit production in the country through production of greening free citrus seedlings.
He urges the funding agencies to come forward for funding to work on citrus greening through a national collaboration among Citrus Research Station, Jaintapur, Sylhet, other educational and research institutes.