Cassava Pest and Disease


Internationally, cassava is an important source of food, animal feed and raw material for industries. Cassava has become Cambodia’s second largest crop after rice and is a significant contributor to the economy.

In Cambodia, cassava is a popular crop among smallholder farmers with few assets and/or insecure land tenure. This is because cassava is relatively easy for farmers to learn how to grow and can be harvested annually to provide quick returns. However, cassava pests and diseases are becoming more common in Cambodia. These include pests and diseases that are new and which farmers have not had to manage before, such as Cassava Witches Broom Disease (WBD) and Cassava Mosaic Disease (CMD). Pest and disease can dramatically reduce crop yields and income for farmers.

Preliminary findings from the ACIAR-funded project Uptake of agricultural technologies amongst farmers in Battambang and Pailin provinces, Cambodia, found that cassava pest and disease was a major concern for smallholder farmers in north-west Cambodia.

Cassava Pest and Disease Knowledge Exchange

As part of the project Uptake of agricultural technologies amongst farmers in Battambang and Pailin provinces, Cambodia, a ‘knowledge exchange’ between farmers and cassava pest and disease experts was held in November/December 2018. The objective of the knowledge exchange was to understand farmer’s existing knowledge and practices and to co-design a pamphlet (in Khmer) that farmers could use to help them identify and manage pest and disease. A Cambodian illustrator/photographer was also involved to generate images that could be used to illustrate specific pest and disease identified by farmers and communicate management practices through images rather than text (for farmers with low literacy levels).

The knowledge exchange included two focus group discussions and interviews with smallholder farmers to understand:

  • What have been smallholder farmers experience of cassava pest and/or disease?
  • Which pests/diseases have farmers experienced?
  • How do farmers identify pest/disease (including what they notice and who helps them with identification)?
  • How do farmers respond to pest/disease (including who helps with response)?
  • Do farmers think cassava pest/diseases are becoming more common?
  • What will farmers do if pest/disease become more common?

Farmers involved in the knowledge exchange were concerned about pest and diseases affecting their cassava crops and reducing yields. In the first few years of growing cassava, farmers reported that pest and disease had not been a big problem. Now pest and disease are a bigger problem and farmers don’t know what to do.

Specific pests and diseases mentioned by farmers were mealybug, witches broom disease, bacterial blight, and mites. Many farmers said they didn’t know what to do, or didn’t do anything, when they saw pests or disease. Some farmers talked to their neighbours or copied what they did. Most farmers did not seek expert help (or when they did seek expert help, they did not find it helpful).

Some farmers wanted to know the cause of specific problems, help to know how to identify signs of pest and disease, and information and what to do if they found signs of pests and disease.

Many farmers said that they would like to rotate crops to improve soil health shift to planting crops other than cassava due to the declining yields. For example, many farmers had aspirations to change from growing cassava to fruit trees (such as mango, durian, etc). To do this, they identified that they would need to work harder and save money.

A number of ‘take-home messages’ for farmers emerged from the knowledge exchange:

  1. You can improve your yield if you control pest and disease on your Cassava crop
  2. There are some simple, cheap and effective ways to improve the health of cassava crops:
    1. Select healthy planting material
    2. Remove and burn diseased plants
    3. Treat pest infestations
    4. Weed and compost to improve soil health
  3. You and your neighbours can both benefit from controlling pest and disease

The knowledge exchange also generated photos, illustrations, video and text to be used to communicate key messages to farmers.

A pamphlet based on the knowledge exchange, “Taking Care of Cassava: Easy ways to control pest and disease” will be available in mid-2021 in hardcopy (printed) and electronic (interactive pdf) format in both Khmer and English.

We encourage you to use, share and provide us with feedback on this research in many ways:

  • If you are a smallholder farmer, you can use the research findings to help you identify, treat and prevent pests and diseases from affecting your cassava crop and yields. We also encourage you to contact us with your experiences of identifying and managing pest and disease – please let us know what questions you have, what approaches you have tried (including what has worked and what hasn’t) and what ideas or suggestions you have and would like to share.
  • If you work with smallholder farmers, you could share the key messages with farmers who are concerned about cassava pest and disease (tip: you may need to adapt the key messages to suit the farmer’s context and work with them to apply the findings to meet their specific needs). We would be pleased to hear about your experiences and suggestions.
  • If you are a researcher, policy maker, practitioner or donor you could use the research findings to inform your own work and share with your networks and through your own distribution channels (eg website, social media, events, etc).