Mandarin farmers in the Hindu Kush Himalayan Region who are once accustomed to the stable climate that supported their mandarin trees, now face an alarming surge in pests and diseases, driven by shrinking water sources and rising temperatures. This unsettling shift in agricultural conditions shows the broader impact of climate change on farming communities across the region. In this story, we look at how farmers are grappling with the growing challenges in Bhutan and Nepal and how experts are seeking sustainable solutions to safeguard the future of this vital cash crop.
In western Nepal’s district of Kailali in Sudurpashchim Province, farmers have started observing the occurrence of new diseases and pests in their orchards. They say shrinking water sources and warmer climatic conditions have aggravated the situation.
Om Raj Kandel, a farmer in Kailali district said “When we initially started cultivating mandarin here, there were wind and storms. The weather was cold. There were no insects due to the chilly weather. However, due to the warmer temperatures these days, insect infestation has started occurring. So, due to the new saplings that we have planted, I suspect that the infestation has spread over.”
Farmers here are supplied four hours of water every eight days, which is stored in a sunken bed. This they say is not sufficient. At Om Raj’s orchard, around a dozen trees are already infected.
Ranjata Kandel, a farmer in Kailali district said “We even carried litres of water in bamboo basket from a source that is one kilometre away from here and watered these saplings. We struggled this much to nurture the saplings. But now it is disheartening to see these saplings infested. If there is enough water, the sapling will be able to thrive.”
Around 20-minute walk downhill, 55-year-old Bhajang, who owns around 400 trees is equally worried. Here, there is a continuous water supply fed from a different source. Because of that, Bhajang, claims his trees are doing comparatively better. However, two of his trees are infected as well and one is about to die.
“In the past, the mandarin trees used to remain green throughout the year as the climate was favorable but now due to extreme weather conditions, the moisture in the soil is drying up which is making the mandarin trees become yellowish and whitish.”
Entomologists and researchers in Nepal say the impacts of climate change is shifting the distribution of insects northwards and the population of insects has been swelling due to warmer climate. This is resulting in the pests becoming more aggressive.
The Chinese citrus fly, an invasive species that initially emerged in eastern Nepal, is now advancing towards the western region. This pest is causing significant damage to citrus crops, with late fruit drop leading to nearly 70 per cent reduction in fruit production. Additionally, the population of the citrus psyllid, a sucking pest that transmits the bacterium responsible for citrus greening disease is also on the rise. Similarly, other pests such as aphids and scale insects have been affecting citrus farming in Nepal.
Sundar Tiwari (PhD), Associate Professor of the Department of Entomology in Agriculture and Forestry University said “The insects have been shifting from one agroecological zones to another agroecological zones. The citrus psyllid issue was initially in the zones below 1000 meters above sea level (masl). And the nursery, we have to think of establishing it above 1000 masl. But what we are doing is that, we grow the seedling below the 1000 masl where the infestation of the insect pest and disease can be more in that location. So now because of the climate change, what has happened is that the farmers are still involved in their old practices. The temperature has been increased.”
Experts at the International Centre for Integrated Mountain Development, ICIMOD say climate change is affecting citrus farming across the Hindu Kush Himalayan Region. They say the resilience of native species is better compared to introduced species. This is because of the mechanisms native plants develop over the years in the same environment.
Surendra Raj Joshi, Sr. Resilient Livelihoods Specialist of ICIMOD said “We need to have systematic approach. The first thing is we need to understand what the particular plant, particular crop or the particular animal, what are the problems that they are facing. The second thing is what are the available good practices, solutions, practices or technologies available in the region. How best we can package these solutions and then sensitise not only the farming communities but also the service providers. Then the fourth thing is how you can scale these solutions up, how you can enhance the uptake. What is happening at the moment, either there is no access of the farming communities to the solutions or the supply of the services is not there.”
At ICIMOD, the Green Resilient Agriculture Productive Ecosystems, GRAPE programme is implemented to enhance sustainable agricultural ecosystems in the Sudurpashchim and Karnali provinces of Nepal. Through the programme, farmers, cooperatives, and small businesses are enabled to build economically viable and climate resilient value chains at the local level.
Oshin Sharma, Research Associate of ICIMOD said “In the Sudurpashchim Province, mainly with the citrus, we are working with farmers in two approaches. One is action research and another is demonstration. We are also working for preserving like in terms of making the orchard water smart and for that we are also demonstrating some irrigation technique and mulching practice so that minimum water is required for the citrus orchard and there is optimum utilisation of the water.”
In Bhutan, the situation is similarly challenging. Mandarin production has been steadily declining. Last year the production has improved, however, it is mainly attributed to the rise in the number of growers. The decline in production is due to a combination of factors, including severe pest and disease outbreaks, the impacts of climate change, and limited knowledge on effective orchard management.
Orchards situated at lower altitudes are now experiencing reduced fruit yields as the optimal growing range for mandarin shifts to higher elevations. These issues collectively contribute to a significant downturn in mandarin cultivation across the country.
Santi Maya Chhetri, a mandarin grower in Gosarling Gewog said “We don’t have mandarin trees below this area. All the trees have dried up and the leaves have fallen. My husband dug and watered the trees, and added manure to them. That way some of them have recovered.”
Similarly, Mon Bdr. Dhahal, who also cultivates mandarin in Tsirang’s Gosarling Gewog said, “People depending on the sale of mandarin are worried. People of lower Gosarling Gewog are the most affected. They used to earn a few hundred thousand ngultrum in the past but now they barely earn a penny.”
Despite the Ministry of Agriculture and Livestock’s efforts to support mandarin growers through orchard management guidance, variety diversification for different agro-ecological zones, and the development of processing facilities and nurseries, growers continue to face numerous challenges.
Phuntsho Wangdi, a coordinator of the National Citrus Repository from ARDC Sub-Centre in Tsirang said “The challenges we face at the moment is, firstly we are limited by planting materials mainly because we have limited nursery production. That is why we are not able to supply enough planting materials to the growers. The next challenge we have is pest and diseases mainly the citrus Huanglongbing disease which is a very deadly disease affecting our citrus industry. Next, we have citrus fruit fly and term borer, and then there is poor nutrient and water management in the field. Lastly, I would like to request all citrus growers to manage your citrus orchards. I would also like to request everyone to plant citrus from a very clean source of planting materials, especially seedlings. When you get seedlings, please get from a very authentic, clean source of nursery.”
As farmers in the Hindu Kush Himalayan Region confront the dual challenges of climate change and pest infestations, there is a need for urgent adaptive strategies and support. Ongoing efforts by researchers and organisations such as ICIMOD are focused on developing sustainable solutions, from advanced irrigation techniques to integrated pest management. While the effects of climate change are growing by the day, these initiatives offer a glimmer of hope for restoring the health of mandarin orchards across the region.
Kipchu
