Diamondback moth

Plutella xylostella

1. Identification

• Common name: Diamondback moth
• Scientific name: Plutella xylostella L.
• Order: Lepidoptera
• Family: Plutellidae

2. Pest description

• Light-green caterpillars, slender, with a characteristic “jumping” movement when disturbed, reaching 8–12 mm.
• Small adults, with a 12–15 mm wingspan, displaying a light diamond-shaped pattern on the forewings.
• Highly mobile species with a great dispersal capacity.
• Key pest of brassicaceous crops worldwide.

3. Main hosts

• Head cabbage.
• Cauliflower, broccoli, kale and other cultivated brassicaceous plants.
• Radish, turnip and various wild brassicaceous plants.

4. Symptoms and damage

• Small and irregular perforations in the leaves, frequently clustered.
• More severe damage in young leaves and in the inner parts of the plants.
• Significant reduction of the leaf area and of the commercial value of the crops.
• In severe attacks, it can completely compromise production.

5. Biological cycle

• Eggs deposited singly or in small groups on the underside of the leaves.
• Caterpillars develop rapidly, completing the larval cycle in 10–14 days.
• Pupation in silken cocoons attached to the surface of the leaves.
• Adults emerge after a few days; several annual generations, accelerated by high temperatures.

6. Monitoring

• Direct observation of caterpillars and typical perforations in the leaves.
• Pheromone traps for detecting adults and tracking flight peaks.
• Regular assessment of seedlings and young leaves, especially during warm periods.
• Monitoring of wild host plants on the margins of the plots.

7. Management measures

• Cultural: elimination of wild brassicaceous plants, crop rotation and destruction of plant debris.
• Preventive: frequent monitoring and integration with phenological models.
• Biological: application of Bacillus thuringiensis during the early caterpillar stages; promotion of natural parasitic species such as Diadegma spp.
• Integrated protection: defining intervention thresholds, judicious use of authorised insecticides and resistance management due to the species' high adaptive capacity.

Bibliographic references

• CABI – Invasive Species Compendium – Plutella xylostella.
• EPPO Global Database – Plutella xylostella.
• Alford, D. V. (2007). Pest and Disease Management Handbook. Blackwell Publishing.
• Furlong, M. J. et al. (2013). Ecology and management of the diamondback moth. Annual Review of Entomology, 58, 517–541.
• Talekar, N. S. et al. (1993). Biology, ecology and management of the diamondback moth. Annual Review of Entomology, 38, 275–301.