Climate change and plant diseases : A threat to Msanipur’s agriculture
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Nongthombam Olivia Devi
Manipur, known for its rich biodiversity, is now grappling with a silent but severe threat—climate change-induced plant diseases. Like every other areas, Manipur’s agriculture sector is also facing the wrath of climate change and global warming, which have far more significant implications on agriculture. In the recent years, Manipur has seen a significant increase in temperature, extreme weather events, unpredictable patterns of rainfall which has threatened the agriculture sector. Such erratic weather conditions have adversely affected the productivity of crops and food grain production. They have also resulted in the increase in incidence and emergence of plant diseases. Climate change can transform minor plant pathogens causing less damage and incidence into major pathogens causing severe threats since it can provide favourable environments for dissemination, reproduction and survival of the pathogen.
Plant disease result from the interaction of a susceptible host, the presence of virulent pathogen and environment conditions favou- rable for the pathogens development-referred to as a “disease triangle”. Climate change significantly influences the environmental factors of this triangle. Increased in temperature results in pathogens that were able to survive in warmer condition to expand in other regions that were previously cooler resulting in emergence of new pathogens that were not previously present in the region. Crop like rice are economically vital for state like Manipur, but such shift have affected the production of rice along with other crops like chilli, tomato, potato etc.
Those diseases that thrive in warm and humid conditionsare favoured by increased evapotranspira-tion from plant due to high temperature and sufficient soil moisture, which further creates humid plant canopy. Rising soil temperature can also increase soil borne pathogens like Fusarium, Rhizoctonia, Macrophomina etc. Prolonged rainfall coupled with high humidity creates favourable condition espe- cially for fungal plant pathogens to spread and thrive. In contrast, low rainfall causes drought which makes the plant weak and more vulnerable to pathogens.
Emerging threats of climate change to important crops in Manipur
Rice, being the backbone in Manipur’s agriculturehas seen a rise in fungal diseases such asBakanae disease (Fusariumfujikuroi), leaf scald of rice (Gerlachiaoryzae), blast (Magnaportheoryzae), brown spot (Helminthospo-riumoryzae), sheath blight (Rhizoctoniasolani) and grain discouloration. There incidences are aggravated by excessive rainfall, temperature fluctuation and flooding past the normal waterlogging conditions. Notably, Bakanae disease and leaf scald of rice were once considered minor issues but have now become significant threats to rice production, exacerbated by changing climatic conditions.
Unpredictable rainfall and change in moisture has resulted in the increased incidence of Phytopthorain- festan causing late blight of potato and tomato, such fungal pathogen prefer 7.2°C to 26.8°C temperature range coupled with high moisture. While low moisture and high temperature makes pathogen like powdery mildews thrive.
Sirarakhong chilli, a GI tagged and valued chilli recognized for its flavour and as an heirloom species are also witnessing a sudden surge in diseases like anthracnose caused by Colletotrichum species and two otherunidentified diseases. As reported in a November 2024 article in The Sangai Express, the incidence of such diseases worsened in the past few years due to unpredictable weather conditions, which may be linked to climate change. Disease incidence coupled with erratic rainfall has further caused the chilli fruits to rot.
Tree bean (Parkiarox-burghii), also known as Yongchak in Manipuri, is a highly prized leguminous tree in Manipur vital for the livelihood of people of Manipur. But in recent years tree beans are slowly drying up and dying in large numbers. This has resulted in the prices to go up and tree beans are now being imported from outside Manipur. These deaths are directly linked to climate changewhich has created favorable conditions for pests and diseases. Insect pest such as the Asian horned beetle (Anoplopho-raglabripennis), stem borer (Bactocera sp.) along with fungal pathogens like Fusa-riumoyxsporum, Verti- cillium wilt, collar rot, Botrydiplodiatheobromae, Pestalotiopsis and Pestalo-tiopsisguepeni etc. can also cause wilting and death of tree bean. The climate change, erratic weather combined with pest and diseases infestation has led to the intensification of tree bean decline in Manipur.
Increased dependency on pesticide
Vegetable like tomato, which are highlyproneto diseases, are laden with pesticides as it has become nearly impossible to grow without heavy reliance on such pesticides.Similarly, diseases like leaf scald of rice have forced farmers to increase pesticide usage, as it remains the only viable method to control its spread.In recent studies, it has been found that pesticide mixture persist both in plant and soil all-round the year. Farmers in Manipur are under additional pressure as a result of the rise in plant disease incidence, severity, and prevalence brought on by climate change.
Mitigation Strategies
1. Adopting Integrated disease management (IDM) that combine multiple methods like cultural, biological, and chemical methods in a holistic way thereby reducing the need of harmful chemicals.
2. Adopting and promoting the use of disease- resistant varieties that are resilient to changing climate conditions can help mitigate loss.
3. Training the farmers about sustainable disease management practices and climate smart agriculture (precision agriculture, crop diversification, agro ecological practices etc.).
4. AI based technologies like mobile apps., satellites can detect, diagnose and monitor the diseases. They can even predict outbreak of a disease giving the farmer’s sufficient time to take up preventive measures.
5. Plant Pathologist and scientist from various institutes, local communities, and Government agencies need to work together in a collaborative way to study the impact of climate change on plant pathogens.
The State can overcome the challenges of climate change by taking up research, promoting techno- logies, sustainable farming, and combining both modern and traditional knowledge to mitigate the risks and safeguard agricultural systems in Manipur. This requires a collaborative and proactive effort.
The writer is Assistant Professor, Department of Plant Pathology, South Asian Institute of Rural and Agricultural Management (SAIRAM), Langjing Achouba, Imphal, Manipur
Manipur, known for its rich biodiversity, is now grappling with a silent but severe threat—climate change-induced plant diseases. Like every other areas, Manipur’s agriculture sector is also facing the wrath of climate change and global warming, which have far more significant implications on agriculture. In the recent years, Manipur has seen a significant increase in temperature, extreme weather events, unpredictable patterns of rainfall which has threatened the agriculture sector. Such erratic weather conditions have adversely affected the productivity of crops and food grain production. They have also resulted in the increase in incidence and emergence of plant diseases. Climate change can transform minor plant pathogens causing less damage and incidence into major pathogens causing severe threats since it can provide favourable environments for dissemination, reproduction and survival of the pathogen.
Plant disease result from the interaction of a susceptible host, the presence of virulent pathogen and environment conditions favou- rable for the pathogens development-referred to as a “disease triangle”. Climate change significantly influences the environmental factors of this triangle. Increased in temperature results in pathogens that were able to survive in warmer condition to expand in other regions that were previously cooler resulting in emergence of new pathogens that were not previously present in the region. Crop like rice are economically vital for state like Manipur, but such shift have affected the production of rice along with other crops like chilli, tomato, potato etc.
Those diseases that thrive in warm and humid conditionsare favoured by increased evapotranspira-tion from plant due to high temperature and sufficient soil moisture, which further creates humid plant canopy. Rising soil temperature can also increase soil borne pathogens like Fusarium, Rhizoctonia, Macrophomina etc. Prolonged rainfall coupled with high humidity creates favourable condition espe- cially for fungal plant pathogens to spread and thrive. In contrast, low rainfall causes drought which makes the plant weak and more vulnerable to pathogens.
Emerging threats of climate change to important crops in Manipur
Rice, being the backbone in Manipur’s agriculturehas seen a rise in fungal diseases such asBakanae disease (Fusariumfujikuroi), leaf scald of rice (Gerlachiaoryzae), blast (Magnaportheoryzae), brown spot (Helminthospo-riumoryzae), sheath blight (Rhizoctoniasolani) and grain discouloration. There incidences are aggravated by excessive rainfall, temperature fluctuation and flooding past the normal waterlogging conditions. Notably, Bakanae disease and leaf scald of rice were once considered minor issues but have now become significant threats to rice production, exacerbated by changing climatic conditions.
Unpredictable rainfall and change in moisture has resulted in the increased incidence of Phytopthorain- festan causing late blight of potato and tomato, such fungal pathogen prefer 7.2°C to 26.8°C temperature range coupled with high moisture. While low moisture and high temperature makes pathogen like powdery mildews thrive.
Sirarakhong chilli, a GI tagged and valued chilli recognized for its flavour and as an heirloom species are also witnessing a sudden surge in diseases like anthracnose caused by Colletotrichum species and two otherunidentified diseases. As reported in a November 2024 article in The Sangai Express, the incidence of such diseases worsened in the past few years due to unpredictable weather conditions, which may be linked to climate change. Disease incidence coupled with erratic rainfall has further caused the chilli fruits to rot.
Tree bean (Parkiarox-burghii), also known as Yongchak in Manipuri, is a highly prized leguminous tree in Manipur vital for the livelihood of people of Manipur. But in recent years tree beans are slowly drying up and dying in large numbers. This has resulted in the prices to go up and tree beans are now being imported from outside Manipur. These deaths are directly linked to climate changewhich has created favorable conditions for pests and diseases. Insect pest such as the Asian horned beetle (Anoplopho-raglabripennis), stem borer (Bactocera sp.) along with fungal pathogens like Fusa-riumoyxsporum, Verti- cillium wilt, collar rot, Botrydiplodiatheobromae, Pestalotiopsis and Pestalo-tiopsisguepeni etc. can also cause wilting and death of tree bean. The climate change, erratic weather combined with pest and diseases infestation has led to the intensification of tree bean decline in Manipur.
Increased dependency on pesticide
Vegetable like tomato, which are highlyproneto diseases, are laden with pesticides as it has become nearly impossible to grow without heavy reliance on such pesticides.Similarly, diseases like leaf scald of rice have forced farmers to increase pesticide usage, as it remains the only viable method to control its spread.In recent studies, it has been found that pesticide mixture persist both in plant and soil all-round the year. Farmers in Manipur are under additional pressure as a result of the rise in plant disease incidence, severity, and prevalence brought on by climate change.
Mitigation Strategies
1. Adopting Integrated disease management (IDM) that combine multiple methods like cultural, biological, and chemical methods in a holistic way thereby reducing the need of harmful chemicals.
2. Adopting and promoting the use of disease- resistant varieties that are resilient to changing climate conditions can help mitigate loss.
3. Training the farmers about sustainable disease management practices and climate smart agriculture (precision agriculture, crop diversification, agro ecological practices etc.).
4. AI based technologies like mobile apps., satellites can detect, diagnose and monitor the diseases. They can even predict outbreak of a disease giving the farmer’s sufficient time to take up preventive measures.
5. Plant Pathologist and scientist from various institutes, local communities, and Government agencies need to work together in a collaborative way to study the impact of climate change on plant pathogens.
The State can overcome the challenges of climate change by taking up research, promoting techno- logies, sustainable farming, and combining both modern and traditional knowledge to mitigate the risks and safeguard agricultural systems in Manipur. This requires a collaborative and proactive effort.
The writer is Assistant Professor, Department of Plant Pathology, South Asian Institute of Rural and Agricultural Management (SAIRAM), Langjing Achouba, Imphal, Manipur