European seed bug

Metopoplax ditomoides

1. Identification

• Common name: European seed bug
• Scientific name: Metopoplax ditomoides A. Costa
• Order: Hemiptera
• Family: Lygaeidae

2. Pest description

• Small adults (3–4 mm), narrow body and dark brown to black coloration.
• Dark head and pronotum, lighter hemelytra with greyish tones.
• Nymphs similar to adults, but without developed wings.
• Very mobile species, frequently observed in large aggregations.
• Feeds mainly on seeds and reproductive structures of grasses.

3. Main hosts

• Wild grasses.
• Autumn-winter cereals.
• Lawns and meadows.
• Herbaceous plants with exposed seeds.

4. Symptoms and damage

• Sucking of sap from seeds and floral structures.
• Reduction of seed viability.
• Quality losses in cereals and meadows.
• Numerous aggregations may cause nuisance in urban areas.
• Occasional entry into buildings during hot and dry periods.

5. Biological cycle

• Several generations per year.
• Adults active in spring and summer.
• Oviposition in grasses and herbaceous plants.
• Nymphs develop rapidly in hot climate.
• Aggregations common in dry, sunny places.

6. Monitoring

• Direct observation of adults and nymphs in grasses and cereals.
• Checking for aggregations on walls, pavements and dry areas.
• Monitoring of damage to seeds and ears.
• Recording of periods of greatest activity (spring and summer).
• Assessment of presence in urban areas and buildings.

7. Management measures

• Cultural: control of wild grasses, management of dry vegetation and cleaning of areas adjacent to buildings.
• Biological: promotion of natural predators such as spiders and generalist insects.
• Integrated protection: regular monitoring, interventions only when necessary, reduction of aggregation sites and use of physical barriers in buildings.

Bibliographic references

• EPPO Global Database – Metopoplax ditomoides.
• CABI Invasive Species Compendium – Lygaeidae associated with grasses.
• Péricart, J. et al. (1998). Heteroptera of the Palearctic Region.
• Rabitsch, W. et al. (2010). Alien true bugs in Europe.