Banana weevil

Cosmopolites sordidus

1. Identification

• Common name: Banana weevil
• Scientific name: Cosmopolites sordidus Germar
• Order: Coleoptera
• Family: Curculionidae

2. Description of the pest

• Adults: Weevils of 10–15 mm, robust body, dark brown to black, with a short rostrum and geniculate antennae; predominantly nocturnal activity, remaining hidden during the day.
• Larvae: Apodous, whitish, with a curved body and brown head; they develop inside the rhizome, excavating extensive galleries.
• Pupae: Formed inside the rhizome, in pupal chambers.
• Eggs: Deposited in fissures at the base of the pseudostem or directly in the rhizome.

3. Main hosts

• Banana, the main and practically exclusive host.
• It may also attack Ensete spp., although with less economic importance.

4. Symptoms and damage

• Borings and galleries in the rhizome, causing necrosis and loss of structural integrity.
• Reduction of the plant's vigour, with small leaves, yellowing and stunted growth.
• Fall or breakage of the pseudostem due to the weakening of the rhizome.
• Significant reduction of production, with small and poorly formed bunches.
• In severe attacks, it may cause death of the plant and rapid dissemination in the plot.

5. Biological cycle

• Continuous cycle in tropical and subtropical climates, with several generations per year.
• Adults live several months and move little, favouring localised outbreaks.
• Eggs deposited at the base of the plant; larvae develop in the rhizome for 4–8 weeks.
• Pupation inside the rhizome; adults emerge and restart the cycle.
• Development favoured by high humidity, mild temperatures and the presence of weakened plant material.

6. Monitoring

• Observation of borings and galleries in the rhizome during routine inspections.
• Evaluation of the plant's vigour, especially in plots with a history of the pest.
• Traps with cut pseudostems or pheromones and volatile attractants for the detection of adults.
• Use of traps with pheromone and attractants for reinforced monitoring in nurseries and vegetative propagation areas.

7. Management measures

• Cultural: Removal and destruction of heavily affected plants; cleaning of rhizome remains; use of healthy planting material; rotation of planting areas; improvement of drainage.
• Preventive: Avoid injuries to the base of the plant; avoid accumulation of cut pseudostems that attract adults; disinfection of tools; use of traps with pseudostems for population reduction; selection of more tolerant varieties when available.
• Integrated protection: Regular monitoring; intervention only when necessary; practices that reduce the survival of larvae in the rhizome and the attractiveness of the plantation; attention to the legal framework, given that C. sordidus is considered a relevant pest in producing areas and is subject to phytosanitary surveillance measures in several countries under Regulation (EU) 2016/2031 and Implementing Regulation (EU) 2019/2072.

Bibliographic references

• EPPO Global Database – Cosmopolites sordidus.
• CABI Invasive Species Compendium – Cosmopolites sordidus.
• European Commission – Regulation (EU) 2016/2031 on protection against quarantine pests.
• European Commission – Implementing Regulation (EU) 2019/2072.
• FAO – Banana pests and diseases technical reports.
• Gold, C. S. et al. (2001). Biology and management of the banana weevil.