A deadly virus

For more than three decades, mandarin (orange) orchards in Bhutan have provided farmers and orange exporters with more than just a livelihood option. In 2014, exports of the fruit brought more than USD 10 million to Bhutan. Unfortunately, this prosperity is now under threat. Over the last few years, Bhutan has joined a set of countries plagued by a virus called ‘citrus greening’, or Huanglongbing. The virus, travelling on the insects that feed off citrus plants, clogs the nutrition system of the plant, making the trees produce bitter, green fruit. Once infected, it is impossible to save the trees and they must be destroyed.

Mandarin export

Metric tonnes of mandarins exported by Bhutan per year [data from: http://www.bhutaniea.org/files/ExportRecords2016.pdf]

Dorji, 56, who lives in a remote village in Bhutan’s southern district of Dagana, recalled how the 500 plants in his orange orchard used to provide enough income to take care of his family of six. In 2012, though, his entire orchard, as well as those of his neighbours, was burnt down due to the infection of citrus greening.

In citrus greening disease the fruit remain green and bitter [image by USDA]

In citrus greening disease the fruit remain green and bitter [image by USDA]

“I was not sad as we were [compensated by being given land for] a new orchard plantation,” Dorji told thethirdpole.net. Unfortunately for Dorji, though, the new plants began to fail a year after they started to bear fruit. Like Dorji, hundreds of orange growers of Dagana, Tsirang, Sarpang, Samtse, Samdrupjongkhar, Zhemgang and PemaGatshel districts are faced with similar problems. Last December, local leaders of Nanglam village in Bhutan’s southwestern district of SamdrupJongkhar said that they might not be able to meet their annual performance agreement to produce 600 metric tonnes of oranges. This was because most trees were either not bearing fruit or the fruits were falling off the trees before ripening.

Climate change also strikes

Thinley Zangpo, an agriculture extension officer in Panbang, where orange growing farmers suffered major losses last year, said, “Other factors, such as erratic rainfall due to climate change, are also affecting flowering and fruition of orange groves.”

Passang Tsheirng, district agriculture officer of Dagana, added, “Since last few year, we have been witnessing drastic changes in rainfall patterns due to which orange trees don’t get the required watering.” These fluctuations affect soil moisture, hampering the growth of the fruits. Earlier, he said, rainfall was timely and people did not need to water orange plants.  However, people do not understand that the change in rainfall pattern could hamper the growth of their orange produce, thus they do not feel the necessity to water their plants.

“We have started encouraging people to water their plants to meet the water requirement of the plants,” he said.

New crops

As a consequence, the farmers are trying to diversify their products. Dorji has started cardamom plantation on two acres of his land, like many other farmers of Dagana and Tsirang. “I believe cardamom is likely to replace oranges in future,” said Dorji. Cardamom requires less land than oranges, and could also fetch a higher price. In Zhemgang district, some farmers have already started growing avocados as a response to low orange production. Similar problems were also reported from other southern districts of Tsirang, Samtse and Sarpang.

cardamom export

Metric tonnes of cardamom exported by Bhutan to Bangladesh per year [data from: http://www.bhutaniea.org/files/ExportRecords2016.pdf]

District agriculture officials told thethirdpole.net that farmers were increasingly growing alternative crops such as kiwi fruit, mangoes, avocados and cardamom in place. The agricultural ministry is trying to encourage farmers to cut down dried citrus trees and plant new ones to avoid spreading of citrus greening. They fear that, “If farmers choose to abandon citrus (orange) over other plant, they would face difficulties when it comes to marketing. Unlike oranges, other fruits face a high degree of market competition.”

 

One comment

  1. This disease-citrus greening disease (HLB-Huanglongbing) is caused by a bacterium ‘Candidatus Liberibacter asiaticus’, a phoem limiting bacterium (not a virus). In Nagpur mandarin grown in central India, it is also observed especially in the areas near the foot hills of Satpura mountain ranges where it is locally called as Waywar (meaning wasteful), cockbund (closed tap). Most of the waywar/cockbund fruit samples were found to be positive for greening bacterium. The severity of the disease can be reduced by foliar application of streptocycline 100 ppm and use of multiple spray combinations of GA3 15-20 ppm and 2,4-D 15 ppm along with CaNO3 (1.5 %), Boron (0.3%), Urea (1.5%) alternatively.

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