Controlling Banana Weevils on Smallholder Farms
7.24 - Controlling Banana Weevils on Smallholder Farms
Eamon Murphy, University of Guelph, Canada
Figure 1: Adult Banana Weevil. Source: Link
Suggested citation for this chapter.
Murphy, E. (2026) Controlling Banana Weevils on Smallholder Farms. In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. farmpedia.org
Introduction to Banana Weevil Control
The banana weevil (Cosmopolites sordidus) is one of the most damaging insect pests affecting banana and plantain (Musa) production worldwide (FAO, 2014) with up to 75% yield losses on individual farms (Bakaze, 2021). The pest is particularly harmful in smallholder farming systems, where bananas and plantains are often grown continuously in the same fields for many years. Over time, this practice allows weevil populations to grow in numbers if they are not properly managed (FAO, 2014; Gold et al., 2001). The larvae (young stage of the insect) are also known and referred to as borers; these larvae tunnel into the corm (the underground stem of the banana/plantain plant) and the pseudostem (the thick stem made from tightly packed leaf bases). These tunnels damage plant tissues and reduce the plant's ability to absorb water and nutrients. As a result, plants become weaker and less productive (Gold et al., 2001).
Figure 2: Banana weevil larvae. Source: Link
Figure 3: Damage on pseudostem caused by larvae. Source: Link
Heavy infestations of banana weevils can cause yield losses of 30–50% in banana and plantain fields (FAO, 2014; Gold et al., 2001). Damage to the corm also weakens the plant's structure, which causes increased risk of plant lodging, which is when plants fall over before harvest because, in this case, of weakened root support. Lodging and reduced plant health significantly shorten the lifespan of banana plants and reduce household income for smallholder farming households.
Banana weevils can be difficult to manage, particularly in perennial banana systems, as the crops remain in the field year-round. Because banana plants are always present, the pest has a continuous food supply and can reproduce throughout the year (Gold et al., 2001). Changes in climate, like higher temperatures and irregular rainfall, can exacerbate banana weevil infestations in many regions (FAO, 2014).
One effective approach to controlling banana weevils is using integrated pest management (IPM). IPM refers to the use of several sustainable, environmentally friendly pest control methods together rather than relying on chemical pesticides alone (Kogan, 1998). Methods like field sanitation, clean planting material, trapping, and biological control are examples of IPMs. IPM approaches are also particularly suitable for smallholder farmers because they are low-cost, rely on locally available materials and labour, which stimulates the local economy, and reduce risks to human health and the environment compared to other strategies (Pretty & Bharucha, 2015).
Benefits of Banana Weevil Control
Effective management of banana weevils provides several benefits for smallholder farmers (FAO, 2014; Bioversity International, 2019). First, reducing weevil populations helps prevent damage to banana corms and pseudostems. This improves plant health and allows banana plants to absorb water and nutrients more effectively. Healthier plants typically produce higher and more stable yields, improving food security and farm income. Second, controlling banana weevils reduces the risk of plant lodging (Gold et al., 2001). Stronger root systems allow banana plants to remain upright until harvest, which reduces crop losses. Third, IPM practices such as paring banana suckers help improve the quality of planting material. Removing eggs and larvae before planting prevents pests from spreading between farms or new plantations (Tushemereirwe et al., 2003). Another important benefit is that many IPM practices have very low financial costs (Pretty & Bharucha, 2015). Techniques such as sanitation and trapping rely mainly on labour and locally available materials rather than purchased inputs (Pretty & Bharucha, 2015). This makes them particularly suitable for smallholder farmers with limited financial resources. Overall, IPM approaches reduce the need for chemical insecticides. Lower pesticide use reduces environmental contamination and decreases health risks for farmers and rural communities (Dubois & Coyne, 2011). Successful banana weevil control usually requires the combination of several IPM practices.
Paring and Treating Banana Suckers
Banana plants are commonly propagated using suckers, which are shoots that grow from the base of mature banana plants. However, suckers may contain banana weevil eggs or larvae that can spread infestations to new fields (Gold et al., 2001). Farmers can reduce this risk by paring (to peel away the outer layer of the banana corm) and treating suckers before planting.
Figure 4: Preparing banana and plantain suckers before planting. Source: Link
Steps for paring suckers:
1. Select healthy suckers from healthy banana plants.
2. Use a knife to remove the outer layers of the sucker.
3. Scrape away damaged or discoloured tissue where larvae may be present.
4. Dip the pared sucker in hot water at 50–55°C for approximately 20 minutes. Allow the sucker to cool before planting in the field.
This method can effectively eliminate banana weevil eggs and larvae before planting, helping to prevent infestations in new plantations (Gold et al., 2001; IITA, 2016).
Cost: Low (labour, materials, and tools for paring).
Field Sanitation
Field sanitation is one of the most important methods for reducing banana weevil populations (Gold et al., 2001). Adult weevils often reproduce in decaying banana plant residues from the last season, including cut pseudostems and corm pieces left in the field after harvest (Gold et al., 2001). Farmers can reduce breeding sites by regularly cleaning their fields.
Recommended sanitation practices include:
● Removing harvested pseudostems from the field
● Chopping plant residues into smaller pieces
● Destroying heavily infested plants
● Keeping banana plantations free of decaying plant material
Regular sanitation disrupts the life cycle of the banana weevil and can significantly reduce pest populations (FAO, 2014; Access Agriculture, 2014).
Trapping Adult Banana Weevils
Banana weevils can also be controlled using pseudostem traps, which are simple traps made from banana plant residues (Gold et al., 2001).
Steps for making pseudostem traps:
Figure 5: Pseudostem trap. Source: Link
1. Cut a fresh banana pseudostem after harvest.
2. Slice the pseudostem lengthwise into two pieces.
3. Place the pieces flat on the soil near the banana plants.
4. Leave the traps overnight.
5. Check traps early in the morning and collect any adult weevils found underneath.
6. Destroy captured weevils to prevent further reproduction.
Pseudostem traps attract adult weevils seeking shelter or food. These traps are inexpensive because they use materials already available on the farm.
Figure 6: Pheromone Trap. Source: Link
In some regions, pheromone traps are also used (Gold et al., 2001). Pheromones are chemical signals that attract adult weevils into traps. These traps can capture large numbers of insects and may be more effective than pseudostem traps alone.
Cost:
Pseudostem traps – very low cost
Pheromone traps – moderate cost
Use of Clean Planting Material
Using clean planting material is essential to prevent the spread of banana weevils between farms (Gold et al., 2001). Farmers should avoid planting suckers taken from heavily infested fields. Extension services, farmer field schools, and agricultural organizations also provide training on identifying healthy planting material and implementing IPM strategies (Masanza et al., 2005).
Benefits
Controlling banana weevils using Integrated Pest Management (IPM techniques) can substantially improve both productivity and household income for smallholder banana and plantain farms. Yield losses from unmanaged Cosmopolites sordidus infestations can increase with successive crop cycles, rising from around 5% in the first cycle to nearly 47% by the fourth cycle (Rukazambuga et al., 1998; as cited in Gold et al., 2001), with some high-pressure regions experiencing 30–75% annual yield losses (Bakaze, 2021). Effective IPM practices, such as paring and hot water treatment of suckers, field sanitation, and pseudostem or pheromone trapping, can recover a significant proportion of these losses, directly translating into more food and higher household income.
Critical Analysis of Banana Weevil IPM Strategies
From an economic perspective, most IPM components are low-cost, relying primarily on labour and locally available materials rather than expensive chemical inputs. However, the value of labour is a critical consideration in smallholder systems. Labour-intensive practices like sanitation, sucker preparation, and trap maintenance require repeated attention throughout the growing season (Gold et al., 2001). In households with limited working adults, the opportunity cost of labour, time that could be spent on other crops, off-farm income, or household responsibilities, can constrain adoption. Despite this, when labour is available, the benefits often outweigh the costs: healthier plants with stronger root systems reduce yield losses, extend plantation longevity, and provide additional food or marketable produce (Pretty & Bharucha, 2015). Cooperative labour arrangements and community-based IPM implementation have been shown to help share labour constraints, making practices more feasible and increasing overall effectiveness (Bioversity International, 2019; Masanza et al., 2005).
Overall, while IPM requires careful attention and time investment, the combination of low financial cost, significant yield recovery, and increased farm sustainability creates a strong benefit for smallholder banana farmers. Practically, every hour invested in IPM can recover multiple times its value in potential lost harvests. This makes it an economically and scientifically worthwhile strategy for managing banana weevils in smallholder systems.
A cost-benefit analysis of the different IPM strategies described is shown in Table 1 below. Sources: Coyne, D. L., et al. (2010), Masanza, M., et al. (2005), Tinzaara, W., et al. (2003), and Gold, C. S., et al. (2001).
Helpful Links to Get Started
References
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