New pests pose threat to food security in Bhutan’s Highlands 

New pests pose threat to food security in Bhutan’s Highlands 

Experts say the best solution is to eat less meat and grow more vegetables to solve most of the world’s problems

Insects have become a threat for farming in Laya. Injury to plants caused by new insects that thrive on leaves and burrowing holes in stems and roots have made the communities concerned about agriculture production. 

Laya is situated in Gasa dzongkhag in the northwest of the country at a height of 3,800 meters above sea level. This area in the region, which is home to 1,108 members of the Layap ethnic group, is rich in ethnic diversity.

Wheat is the main staple food, even if cattle (yaks) are the people’s main source of food and money. The highlanders began to grow vegetables in greenhouses a few years ago, including spinach, chillies, broccoli, beans, cucumbers, and cabbage. This has made it easier for them to obtain food from their own farm, eliminating the challenge of making the one-day trip to Punakha to purchase necessities.

The Department of Agriculture (DoA) introduced greenhouse vegetable plantations in the highlands to ensure the sustainable social and economic well-being of the Bhutanese people through adequate access to food and natural resources.

The common pests of the hot region, however, have been seen by the farmers of all seven villages of Laya gewog (administrative area of grouped villages), infecting their wheat and barley as well as their greenhouse-grown crops. Additionally, farmers are starting to notice how climate change is affecting their crop yields of vegetables.

According to the meteorological record for the region, there has been a rise of 3 °C in temperature in Gasa in the past two years.

Wangmo from Nyelo, said that the introduction of new vegetable plantations has added varieties to their menu. She said it has helped to reduce investment for the vegetables and she hopes it sustains.

Lhamo, said rural communities of Laya harvested vegetables at the right stage of maturity with the best taste and quality for the past few years. But now it has changed. “We are not getting the same vegetables and crops yields as before and we are concerned about future food sustainability,” she said.

A homestay owner, Tshering from Toko village said that food wastage is not acceptable anywhere in the world considering resources required to grow foods. He said, “Loss of harvest is one of the most devastating factors discouraging new investments into and expansion of farm operations.”

Greenhouse vegetable plantations have helped Tshering to improve food services to his guests but he doesn’t foresee the same trend continuing.

New pests pose threat to food security in Bhutan’s Highlands 

A young farmer, Tshering Yangden, 15, from Lungo is concerned about future food security if plant infestation continues saying the population in their communities are increasing and definitely food requirements would surge.

Meanwhile, Passang from Chongra village said that influence on plant pathogens that are often inconsistent is triggered by climate change.

It has been a few years since farmers stopped cultivating mustard and farmers said that their barley is not ripening in time. 

Thekpa Tshering, the village chief of Lungo, claimed that no bugs had ever harmed their harvests or vegetables in the past. He claimed that the invasion began in 2015, nevertheless. He claimed that pests were still active during the winter.

The same was reiterated by Dorji, 42, from Lungo village, who said that the farmers of Laya are experiencing new pest challenges infesting their plants. The villagers are noticing more infestation during the tender stages of the plants.

New pests pose threat to food security in Bhutan’s Highlands 

The farmers in Laya Khatoed deal with comparable difficulties. Sangya Zam, 30, from Khatoed, claimed that since 2018, new pests have been infesting her community’s farms. Farmers have noticed that nighttime is when vegetables, like onions and garlic, are most vulnerable to damage.

The Laya farmers have observed a decline in their crop and vegetable yield over time. They stated that if they continue to experience these impacts on an annual basis, not only their neighborhood but the entire country will experience a food crisis.

Views from officials and experts

Rising temperatures have altered the agroecological conditions in mountain cropping zones and pastures, according to Dr. Abid Hussain, Senior Economist and Food Systems Specialist, Livelihoods at the International Centre for Integrated Mountain Development (ICIMOD).

According to the senior specialist, as temperatures rise, high-altitude pastures and single-cropping zones become more conducive to multiple crop cultivation, whereas valleys and relatively low-altitude hilly areas experience increased pest infestation. This has been observed in the Hindu-Kush Himalaya (including Bhutan) over the last few decades.

The resident lecturer in mountain ecology at the school for field studies/Bhutan ecological society, Dr (PhD) Norbu Wangdi said that climate change directly affects the pests’ reproduction, development and survival and dispersal. Insects are “poikilothermic” or “cold blooded” organisms- the temperature of their body depends on the temperature of the environment.

Increased temperature and increased atmospheric CO2 levels are the main drivers of climate change which significantly affect the population dynamics of insect pests, resulting in increased pest infestation according to the resident lecturer.

Dr Norbu Wangdi added that climate change creates new ecological niches and provide opportunities for insects to establish and spread in new geographic regions and shift from one region to another that could lead to huge economic crop losses ultimately affecting the food security of the highlanders.

The administrative agriculture extension officer, Tshelthrim, shared that with the introduction of greenhouse plantation, pests like cabbage white butterfly, mites and aphids have started to infest. He said that cabbage white butterflies infest cabbage, cauliflower and broccoli while aphids infest tender vegetables and chilli plants.

Similarly, the agriculture extension officer of Lunana, Yonten Phunthso, also reported similar problems faced by the farmers. Under his extension, greenhouse vegetables are affected by aphids and white butterflies.

The extension officer said infestation by common pests even in higher altitude is a concern. Though it is not a concern at the economic threshold, he said, “food security impacted by climate issues is a concern.”

 As pests move to more hospitable environments and climates in search of food sources, Sherab Wangchuk, FAO Bhutan’s National Program Development Specialist, explained that increasing temperatures and precipitation would also result in longer pest survival as they spread into new geographic areas, particularly high-altitude areas.

According to the Food and Agriculture Organization (FoA), Bhutan, the nation has discovered 17 new wasp species, including the hornet-like Eumeninae (Potter wasp), Polistinae (paper wasp), and Vespinae (paper wasp).

However, Associate Professor of Ecology, Department of Biosciences, University of Exeter, UK, Dr Dan Bebber, (PhD) said that it is impossible to know if this is due to climate change without a detailed study of both the pests and the recent changes in weather conditions in the area. Many factors can affect pest impacts, for example changes in management or the kind of crops planted.

“It is possible that the changes in cropping (vegetables in greenhouses) have encouraged pests to grow in the area,” and “it could impact food security if farmers cannot control the pests,” Dr Dan Bebber added.


The most popular method of pest management among farmers in Bhutan is the use of natural insecticides. The DoA advised farmers in highland areas to utilize organic pest management techniques.

The farmers of Laya utilize locally produced insecticides to manage the pests because they are aware of the consequences of artificial fertilizers. To get rid of the bugs, they utilize cow urine, garlic leaves, and fermented chillies.

The gewog (administrative) agriculture extension officials stated that in addition to being required to use biopesticides, farmers are also instructed in the usage of nets to fend off pests and the use of ash. Additionally, the growers are told to only open the greenhouse during the day and close it at night.

Native resistant crop species need to be encouraged in highlands, according to changing agroecological circumstances, according to Senior Economist and Food Systems Specialist, Livelihoods, Dr. Abid Hussain of ICIMOD. The probability of swift pest infestations will grow with the introduction of cultivars or crops that are bug vulnerable.

He recommended an awareness program for farmers on pest-management and focus more on climate resilient and native varieties and adapt the integrated pest management (IPM) practices with proper training on IPM through government programs.

Dr Arbid Hussain said that developing countries should provide financial support and share technology for better adaptation and improving resilience in food production systems.

Dr Norbu Wangdi said that adopting and implementing climate change adaptation measures seems to be the only plausible solution to manage the existing risks and reducing the potential risks from climate change impacts. He also said that adaptive strategies such as modified IPM practices, monitoring climatic changes and insect populations, and use of modeling prediction tools for pest prediction could be applied.

Besides all must try to minimize CO2 emission, Dr Norbu Wangdi said that developed countries should achieve their emission reduction targets. If not, he said, “climate change impacts are expected to increase the incidences of pest infestation and crop damage, facing a high risk of significant economic losses and a challenge to human food security. So, we must act now.”

Dr Dan Bebber suggested detailed assessments of the kind of pests causing the biggest problems, why they are causing these problems, and then analyse what management options are available and affordable for growers; resistant varieties, pesticides, or other control measures.

As mitigations for impacts of climate change are very diverse and generally negative, Associate Professor said that people need to switch to renewable energy, increase energy efficiency, and reduce wasteful practices like food waste, use of plastics, and eating meat. “A simple solution is to eat less meat and grow more vegetables. That will solve most of the world’s problems,” he said.

The National Program Development Specialist of FAO Bhutan, Sherab Wangchuk, said that the country can adapt IPM at the national level and pest surveillance at the local level.

He said that the carbon emitting countries should switch to more green technologies by investing in research and technologies and commit to support less privileged countries for the common good. 

This story is published with support from Thomson Reuters Foundations as part of Reporting on Food Security and Rural Development for South Asian journalists.

New pests pose threat to food security in Bhutan’s Highlands