Colorado Potato Beetle

Leptinotarsa decemlineata

1. Identification

• Common name: Colorado potato beetle
• Scientific name: Leptinotarsa decemlineata Say
• Order: Coleoptera
• Family: Chrysomelidae

2. Pest description

• Adults: Oval and convex body, about 10 mm; yellow elytra with 10 black stripes; orange head and pronotum with dark spots.
• Larvae: Soft body, orange-red to pinkish; dark head; two rows of lateral black spots; more intense colouration in the last instars.
• Eggs: Orange-yellow, oval, laid in grouped clutches on the underside of the leaves.

3. Main hosts

• Plants of the Solanaceae family, especially potato, tomato, eggplant and wild solanaceous plants such as Solanum nigrum.

4. Symptoms and damage

• Intense defoliation caused by adults and larvae.
• Reduction of the photosynthetic area and decrease of plant vigour.
• Significant production losses, especially in early attacks.
• Possible complete destruction of the foliage in severe infestations.
• Eggs and larvae easily observable on the underside of the leaves.

5. Biological cycle

• Several generations per year, depending on the climate.
• Overwintering as an adult in the soil.
• Emergence in spring followed by egg-laying in masses on the underside of the leaves.
• Larval development in four instars before pupation in the soil.
• Cycle favoured by mild to high temperatures and the continuous presence of hosts.

6. Monitoring

• Regular observation of the crop, especially the underside of the leaves and the plot edges.
• Counting of eggs, larvae and adults to support decision-making.
• Assessment of the percentage of defoliation.
• Recording of climatic conditions favourable to pest development.

7. Management measures

• Cultural: Crop rotation avoiding solanaceous plants; elimination of wild host plants; deep ploughing in winter to expose overwintering adults.
• Biological: Conservation of natural enemies such as Podisus maculiventris, Perillus bioculatus and egg parasitoids; application of Bacillus thuringiensis var. tenebrionis on young larvae.
• Integrated protection: Intervention only when population levels reach economic thresholds; rotation of active substances to avoid resistance; preference for selective methods compatible with beneficials.

Bibliographic references

• Alyokhin, A., et al. (2013). Colorado Potato Beetle: Insecticide Resistance and Management.
• Hare, J. D. (1990). Ecology and Management of the Colorado Potato Beetle.
• Capinera, J. L. (2001). Handbook of Vegetable Pests.
• CABI Invasive Species Compendium – Leptinotarsa decemlineata.