Highlanders face plant health challenges posed by climate change

Highlanders face plant health challenges posed by climate change

With vegetables and crops pest infestation, the communities of Laya are concerned of future food security

Introduction of greenhouse vegetable plantation has instilled plight to the farmers of Laya. Expecting no bleak future, the farmers of the community dreamt of better yields of new vegetables which would add varieties of cushion to their village age-old vegetables.

Could be considered as one of the educated farmers in the village, Tshoki, 31, from Nyelu was excited to take up new greenhouse vegetable plantation. Initially, she could harvest good quantity of qualitative organic vegetables for the first time in the history of Laya.

However, Tshoki and other farmers are noticing the climate changes and its impact on harvests of vegetables and crops in Laya.

The fact is that earth’s climate has already changed and will continue to do so in the foreseeable future, unless human reduce impacting activities. World climate has undergone changes which disrupt these more normal. The epochal changes consequently abet trends that in turn will cause scenarios that threat human life and behavior.

Climate change is one of the greatest challenges the plant health community is facing. Climate change is already impacting agriculture.  A new study finds that many crop pests and pathogens are spreading. (Scientific American)

Pests are major causes of crop yield losses. According to the UN Food and Agriculture Organization (FAO), between 20 and 40 % of global crop yields are reduced each year due to damage caused by plant pests (insects and diseases).

Climate change is exacerbating food insecurity, and its negative impacts will worsen over time. This is happening via several pathways, among which plant pests are a leading cause. In fact, there are many possible pathways through which climate change may impact plant pests, including ecology, spatial distribution, and food chains.

Bhutan is no exception and the dynamics of crop diseases and pest influx are changing rapidly due to changing climate. The common pests of lowland have started to infect the plants of highland. Managing them has, therefore, become a huge challenge in the country.

In off beat destinations, Laya is located northwestern part of the country at an altitude of 3800 meters above sea level in Gasa dzongkhag. Inhabited by about 1,108 ethnic people known as Layaps, this pocket of the region is indeed a treasure trove of culture. Though the primary source of food and income of these nomads are from the yaks, wheat is also the main staple food of them. Few years back, these highlanders started to plants vegetables in green house which helped them procure food from their own farm easing the hurdle they face going to Punakha to buy essential items.

The rising temperatures are having direct effect on pests and diseases on crops even in higher altitude. There is rise of temperature by 3C in Gasa in past two years. The farmers of all seven villages of Laya Gewog have witnessed the common pests of hot region infecting their vegetables grown in the green house and even wheat and barley. The farmers said the insecticides have started harming their only cereal-wheat and chilies and cabbages grown in the green house. 

Sonam Dorji, 42, from Lungo village said that the farmers of Laya are experiencing new pest challenges for their plants.

Radish and turnip are age old grown vegetables and barley, mustard and wheat are their long grown main crops. Spinach, chili, broccoli, beans, cucumber and cabbages are new vegetables grown by the highlanders in greenhouse.  To ensure sustainable social and economic well-being of the Bhutanese people through adequate access to food and natural resources, the Department of Agriculture (DOA) had introduced the greenhouse vegetable plantation in highland.

Of late, Sonam Dorji said the community has witnessed pest infestation both for age-old grown crops and vegetables and newly introduced vegetables. He said that mostly cabbage is damaged by the pests.

Pema Choki, 31, from Nyelo said that with the introduction of new vegetables plantation have added varieties to their menu. She said it has helped to reduce investment for the vegetables and had hope for sustainability.

However, she said that it doesn’t seems true as “crops and vegetables are damaged by the insects.”

Dorji from the same village claims that new plant diseases are impacts of climate change. He blames influence on plant pathogens are often inconsistent triggered by climate change. “Unlike before, our barley cannot ripe on time,” he said.

Even a young class VIII dropped farmer, Tshering Yangden, 15, from Lungo is concerned of crops and vegetables damages. She says population in the community is increasing and definitely food requirement would upswing. “I am concern of future food security if our food plants are infested,” she laments. 

She plans to expand her greenhouse plantation. However, she is discouraged by the unfavorable happenings in her garden.

Similar challenges are faced by the farmers of Laya Khatoed. Sangya Zam, 30, from Khatoed said that the famers of her village have been witnessing infestation of new pests to their crops and vegetables since 2018.

Planted with much struggle and expenses, Sangay Zam said, “our crops and vegetables are consumed by insects.” Especially, she observed that vegetables are damaged at night, mostly, onions and garlics.

For the last one -two years, armyworms have started to damage paddy and buckwheat, according to the farmers of Khatoed.

The farmers of Laya noticed that their crop and vegetable production has decreased over the years. They shared that if the farmers encounter such affects every year, not only their community but whole nation will face food crisis.

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

Integrating cross-disciplinary knowledge broadening the perspective beyond agriculture, agriculture extension officer admits the impacts are due to climate change. He said that further the scale would accelerate with the evolution and changing geographic distribution, implicating pathogens.

Aphids are small, soft-bodied insects that use their piercing-sucking mouthparts to feed on the sap of living plants usually found in warmer regions generally about 1/16th to 1/8th of an inch long (2-4mm).

Mites are tiny home and garden pests with two body segments and sucking mouthparts which is also normally found in hot places.

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

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

The Senior Economist and Food Systems Specialist, Livelihoods of International Centre for Integrated Mountain Development (ICIMOD), Dr Abid Hussain, said that the rise in temperature is resulting in changes in agroecological conditions in mountain cropping zones and pastures. He said, “climate change is one of the factors resulting in the increased pest infestation in agriculture in hilly and mountain areas (highlands).”

The senior specialist said that in the Hindu-Kush Himalaya (including Bhutan), it has been observed in last couple of decades that due to temperature rise, high-altitude pastures and single cropping zones are getting favorable for cultivation of multiple crops, and valleys and relatively low altitude hilly areas are facing increased pest infestation. In high altitude mountains, the elevation of snowline is also gradually increasing, that favors the shift of crop cultivation to high altitudes (single cropping zones and pastures) where cultivation was either limited or was not possible in the past due to persistent snow cover. In terms of an increase in cultivable area, it is a positive sign, however this shift is likely to increase the chances of human-wildlife conflict and invasion of crops pests to high altitude areas.

Dr Arbid Hussian said an increase in temperature in highlands favors the conditions for pests to migrate from lowlands to highlands and to survive and grow in highlands. Under temperature rise, crop plants have also become more susceptible to attack by insect-pests because of weakening of their own defensive system resulting in pest outbreaks and more crop damage.

An increase pest infestation in highlands has negatively impacted crop productivity deteriorating the quality and safety in production systems according to the senior specialist.  Citing the example of increased pest infestation has forced farmers to increase the use of chemical pesticides on crops including fruits in Pakistan (Hunza valley) and India (Ladakh), Dr Arbid said “It has severe impacts on the safety of food production in the highlands.”

The National Program Development Specialist of FAO Bhutan, Sherab Wangchuk, said that the rising temperatures will make insect pests to spread and expansion into new geographical areas, especially to high altitude areas. He said that rising temperatures precipitation would also lead to longer survival of pests. Insect pest migrate to more favorable environment and climate to find food sources.

Many current agricultural pests can thrive, despite what we see as unpredictability, by feeding on a wide variety of plant hosts and by possessing the ability to move throughout the landscape to find suitable habitats.

An associate professor from the of College of Natural Resources (CNR), Sonam Tashi said that pests migrate to more suitable climatic conditions and infestation could be because of poor management practices, including lack of nutrient management, which is true in Bhutan.

He said that the pests migrate including for food, resources, suitable weather conditions.  In coming years, perhaps, climate change could further speed up pest migration as all animals, including pests would want to survive and thrive. 

An associate professor said that pest infestation means food loss through crop damage and impact on quality and the associated cost in managing new pests. He said that climate change could impact all regions, and those regions which are dependent more on agriculture could be impacted even more if business as usual continues because food production, to a large extent, is dependent on weather conditions.

The National Program Development Specialist said that loss of crops to pest is a concern for Bhutan, especially arrival of new pest every year (eg. army warm). Recently, the country also recorded about 17 new wasp species which consist of Eumeninae (Potter wasp), Polistinae (Paper wasp) and Vespinae (hornets). Therefore, “the pest is a threat to food security,” he said.

The minister for the Ministry of Agriculture and Livestock, Yeshey Penjor, earlier said with the change in weather patterns would cause natural disasters and will destroy communication infrastructure which will disrupt food distribution.

The director general of the International Technology Bureau of Rural Development Administration, Korea, Dr Taek-Ryon said that Bhutan is not exempted from the food security problem during the sixth General Assembly of the Asian Food and Agriculture Cooperation Initiative (AFACI) last year. He said, “Mostly lower-income people are vulnerable to face the food shortage.”


Bhutan aims for organic farming, being conscious of public health. Farmers are advised to use natural pesticides. It is the most common pest control method which can be done by anyone. The farmers of highland communities are instructed to use natural pest control by the DoA.

Understanding the effects of chemical fertilizers, the farmers of Laya use locally made pesticides to control the pests. They use chili ferment, garlic leaves and cow urine to control the pests.

Dechen Wangmo, 26, from Pazhi village said that the villagers are not allowed to use chemical fertilizers. However, farmers of Khatoed admit they had to use even chemical fertilizers.

The gewog agriculture extension officer, Tshelthrim, said that the agriculture official advice to use bio-pests.

The agriculture extension officer of Lunana, Yonten Phunthso, said that besides farmers are mandated to use bio-pesticides, the local agriculture office had taught farmers to use net to stop the pest and apply the ash. The farmers are also instructed to close the greenhouse at night and open only during the day.

The Senior Economist and Food Systems Specialist, Livelihoods of ICIMOD, Dr Abid Hussain said that the measures need to start from national level with a periodic review and revisions in the agroecological zonation. He said, “According to changing agroecological conditions, native resistant crops species need to be promoted in highlands. The introduction of insect susceptible cultivars or crops will increase the risk of rapid pest infestations.” He also said that the governments also need to launch an awareness program of farmers on pest-management in the changing climate.

At local level, Dr Abid Hussain said that farmers can focus more on climate resilient and native varieties. This is that they can review and reschedule the cropping calendars and adjust the sowing and harvesting time of crops; and they can manage a sufficient time break between the harvest of previous crop and sowing of next crop. They can also adapt the integrated pest management (IPM) practices with proper training on IPM through government program.

The Senior Economist and Food Systems Specialist said that internationally, there is need to acknowledge the loss of crop productivity caused by climate change induced pest infestations. Governments including Bhutan can pay attention to improve the evidence on attribution of pest infestations to climate change and consider the pest-infestations under the slow onset impacts of climate change in their national loss and damage assessment frameworks. He said it will help the governments to get adequate funds in future from the global ‘loss and damage fund’ (established in COP 27 in Egypt; this fund aims to provide financial assistance to nations most vulnerable and impacted by the effects of climate change. In future this fund will be operationalized) to take measures for both slow onset impacts and extreme events caused by climate change.

Dr Arbid Hussain said that the developing countries should support in terms of finance and technology for better adaptation and improving resilience in food production systems. If not, he said that it will impact the sustainability of food systems not only in highlands but also at national levels in the developing world through negatively impacting the crop productivity, increasing production costs, affecting food safety (shift from organic to inorganic production), and resulting in high food prices (inadequate economic access to food).

The National Program Development Specialist of FAO Bhutan, Sherab Wangchuk, said that integrated pest management is required at the national level and surveillance of pest at the local level. Research on pest management plays an important role at the global level and also sharing of research findings and innovative solutions.

The organization recommends sustainable management of forests and focus on the use of marginal lands and implementation of pest resistant bio-tech crops through research and innovation.

The National Program Development Specialist said that the carbon emitting countries should commit to support climate finance for loss and damage by climate induced disasters, and finance mitigation and adaptation programs, supporting transfer of technologies, including digital.

As there won’t be food without agriculture, the Associate Professor, Sonam Tashi said that there is need constant study of nature and make farming more robust and resilient through adopting technologies and practices that conserve the ecosystem. Without a healthy ecosystem, he said, “the food production will not be possible or sustainable.” Simple practices such as diversified crop rotation, crop covering, use of organic mulch and manure and systematic integrated farming system could contribute to building resilience are recommended.

Asking people to study and work with nature, Sonam Tashi 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. 

Climate change can pose serious problem such as food security, diseases, pests, water security, disasters- infrastructures damages, rising seas levels- pest migration, new pest and diseases. If not taken seriously, impacts will be far devastating for the world. Therefore, the climate activists calls commitment for carbon negative or at-lest net-zero both at the national and international level.

Highlanders face plant health challenges posed by climate change

This story is published with the support from Bhutan Media Foundation funded by Canada Fund for Local Initiatives