Rejuvenating Citrus: enriching lives in Nepal

Agriculture is the vital part of the economy of my country and its development is crucial for the development of the country’s economy as a whole. Nearly four-fifths of all Nepalese households are essentially farm households, whose income is primarily from agricultural sources. I am in a long journey to cultivate new knowledge and ideas in order to bring about change and to improve functionality.

The unique agro-ecological zones favored by altitudes, topography and aspect within Nepal offer an immense opportunity for growing different types of fruits, vegetables, flowers, spices and other plantation crops. Recent statistics shows agriculture contributes more than 27 percent of the total GDP of Nepal, where the contribution of fruit is 7 percent of total AGDP. Among fruit, citrus contributes to 22.44% of the total production, of which mandarin shares 66.97% of the total citrus production. Nepal ranks 20th in the world’s mandarin production and contributes 0.97 percent of the total AGDP.

Cultivation of mandarin is one of the major economic activities in the mid-hills (550-1300m) of Nepal. It is a very popular fruit in Kavre, Nepal (where I worked as researcher) grown on a semi commercial scale. Mandarin orange (Nepal’s Gold) cultivation provides nutrition, employment to the people, is a source of income and maintains environmental harmony.

Huanglongbing (HLB), also known as citrus greening disease (CGD) is a century old disease in citrus plantations. It affects not only the quality of citrus fruit but also the fruit bearing age of citrus trees. The production of citrus is declining in Nepal because of this problem. The citrus boom has gotten out of hand and many lost their dreams of citrus success here in Nepal.  I have a vivid memory of the production of vinegar from lime in my hometown Pokhara, when I was at my early childhood. Nowadays I see no citrus trees there. Scientists believe that up to 39-95% of the mandarin trees have been infected with this greening disease in Pokhara valley. In Kavre the preliminary symptoms of this disease are being observed. The symptoms are often mistaken for nutritional deficiencies so it has been difficult for extension workers to suggest to farmers that citrus decline is because of HLB and provide managerial advice for citrus rejuvenation. Moreover, the only definitive test for HLB is PCR is based on DNA testing, which is not suitable for large number of samples as it is time consuming as well as expensive in Nepalese conditions.

During my stay there, I searched for the best method ‘SCRATCH Test’ for identification of HLB, which is cheap and rapid and without a need for sophisticated equipment. This method is an iodine based starch test which is a rapid, simple field diagnostic test that could be used to prescreen samples intended for PCR analysis. Indeed, I carried out this test in different citrus fields of Kavre and got positive results.

The widely applicable method could be used to hasten the detection of HLB among the mandarins produced in Kavre district. Mandarin producers then could be recommended on the appropriate measures for rejuvenating declined citrus by supplying deficient nutrients as well as by introducing new cultivars of mandarin resistant to HLB. The screened positive samples could be destroyed.

I have already carried out the preliminary test at the major citrus growing hubs of Kavre district of Nepal and mapped them using GPS. Samples were collected from trees expressing symptoms and were tested with the scratch test. Some of the samples were recorded with positive results. In June, the test will be carried out and samples with positive results will be identified and tagged. Then they will be brought to lab for PCR analysis to confirm citrus greening. I remain resolute on finding a way to prevent citrus greening and cynosure for alternative cures.

At the first stage, I am going to form an innovative consortium of researchers, professors, government officers, technicians, extension workers, students and farmers to accelerate the pace of this project. We will be first working in Kavre district of Nepal, then move to other parts of Nepal.

Secondly, data will be updated in the already developed GPS map and recommendations will be made accordingly so that we may contribute to rejuvenate the declined citrus trees. In the future, routine monitoring will be carried out to identify problems, production status and a database will be developed.

Thirdly, our team will focus on coordinating with local nurseries to produce resistant varieties to replace the HLB detected trees. A seminar, workshops and trainings will be conducted among farmers about the management of citrus orchards and they will be provided with productive resistant cultivars of citrus. Farmers, in whose field symptomatic expression is not because of HLB, will be provided with hands on knowledge about managing citrus orchards, replacing old trees. The productive local cultivars will be used to produce scions at their field. Farmers will then be capable to handle their orchard as well as disseminate the knowledge they have gained.

The primary beneficiaries of this project will be the farmers in the research area whose livelihood is jeopardized and who are willing to replace the citrus with vegetable and agronomic crops. Farmers who used to make NRs. 500,000 per annum from their farm at present hardly earn NRs.100,000. Some of the orchards have already collapsed, because of the unidentified problem. These farmers will be the primary focus and their citrus orchards will be diagnosed and recommendations will be made accordingly. They will be provided with training on improved commercial farming of orchard, so that they will profit from this enterprise by selling their product to other districts of Nepal and even to India, which they used to do in earlier years.  Next, the widely applicable scratch method could be used to hasten the detection of HLB throughout the mandarins produced in Kavre district. Mandarin producers then could be provided with appropriate measures that could be applied in their farms for rejuvenating declined citrus trees either through the supply of deficient nutrients or by introducing new cultivars of mandarin resistant to HLB after destroying samples suffering with HLB. I hope the result of this project will be exemplary not only at national level; it will be bodacious at international level too.

Globally, despite the large sums of money spent on research and hundreds of scientists working at a frenzied pace, no cure or prevention has yet been developed for HLB. The industry of ‘Nepal’s Gold’ is in peril and should be prevented from death. I have a hope that these trees will survive and it is possible to create a golden future for citrus growers of Nepal to make it a citrus superpower. Bacteriocides, heat therapy, genetic engineering which are still at an early stage for citrus industries would not be possible at our level. We would identify through a scratch test, propagate resistant local varieties, suggest genuine orchard management and create a golden example of citrus rejuvenation.

Kiran Timilsina, Nepal



441 comments

  1. The scratch test for identifying HLB can really be a boon for those marginalized farmers who don’t really know what has happened to their “gold” . Best wishes and I am willing to support on this project if any possible.

    Like

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