Damaging citrus greening disease, which causes the top leaves of citrus plants to turn yellow and dry out, and is a problem for citrus farmers worldwide, has been confirmed in Bangladesh for the first time.

The symptoms of the disease have long been observed in Bangladesh but were previously blamed on commonplace nutritional deficiencies, including inadequate zinc. Recently scientists have been able to isolate the bacterium that causes citrus greening disease from several local samples of mandarin and sweet orange trees, locally known as komola and malta.

"We visited Moulvibazar, Sylhet and Chittagong to collect samples to test," says Prof. Rashidul Islam of the Bangladesh Agricultural University's department of plant pathology, who led the three-member research team. "We found the disease occurring in a high percentage of samples."

According to the research team members, who also represent the Bangladesh Agricultural Research Institute in Gazipur, the bacterium candidatus liberibacter asiaticus was first isolated through polymerase

change reaction testing and genetic sequencing processes last month.

The presence of the disease has particular implications for crop expansion via grafting, the scientists warn. "We hope the confirmed detection of this disease will promote further research," says Bangladesh Agricultural Research Institute's scientific officer and team member Monirul Hassan Tipu. The ultimate goal is to develop measures to address the threat to citrus production.

Since 2013 the agriculture ministry has undertaken a number of measures to develop and expand citrus production in 67 upazilas of 17 districts. With citrus crops currently covering 2,832 hectares the aim is to bring a further 800 hectares under citrus cultivation by2021.

Dr. Md Azmatulla, the principal scientific officer at Bangladesh Agricultural Research Institute who is also the director of the government's Citrus Development Project says identifying the disease represents a step forward in better managing the citrus fruit cultivation expansion that has been underway for two decades.

The hope has been to reduce reliance on imported citrus fruits, with Bangladesh currently spending large amounts of money to import around 1.1 lakh tonnes each year in order to meet a national demand for citrus fruits of 2.5 lakh tonnes per annum.

According to the scientists citrus greening disease could undermine national expansion efforts and create significant citrus fruit shortages in the future. If this disease can be checked, say the scientists, the government's plan to reduce dependence on imported citrus fruit will have the best chance of success.