Abyssinian grey weevil

Systematic position: The Abyssinian grey weevil Tanymecus abyssinicus is classified within the order Coleoptera and the family Curculionidae. It is recognized as a significant agricultural pest, particularly known for its impact on staple crops in the Horn of Africa, where it causes consistent yield losses.

Crops affected: This beetle acts as a primary pest for various cereal species. It exhibits a strong preference for teff (Eragrostis tef), wheat, and barley. Additionally, it has been observed attacking maize and sorghum crops, making it a threat to food security in regions where these crops are central to agricultural production.

Biology and life cycle: The life cycle of Tanymecus abyssinicus is synchronized with the regional rainy seasons. Overwintering occurs in the soil, with adults emerging as environmental conditions become favorable. Females deposit eggs in the soil near the host plant roots, leading to a life cycle that involves both subterranean larval development and above-ground adult feeding.

Damage and pest status: The adult weevils cause the most visible damage by feeding on emerging seedlings, frequently leading to stand failure and the need for reseeding. Meanwhile, larvae feed on the roots of young plants, which stunts plant growth, reduces the efficiency of nutrient uptake, and makes the crops more susceptible to environmental stressors like drought.

• Crop rotation with non-host plants to reduce populations.
• Deep tillage practices to expose larvae and pupae to predators.
• Seed treatment with systemic insecticides prior to planting.
• Monitoring of adult migration during the early crop development stage.
• Integrated pest management approaches to maintain economic thresholds.