Grass Thrips

Anaphothrips obscurus

1. Identification

• Common name: Grass thrips
• Scientific name: Anaphothrips obscurus Müller
• Order: Thysanoptera
• Family: Thripidae

2. Pest description

• Small-sized thrips species, with a narrow body and yellowish to brown coloration.
• Pale nymphs, generally present on young leaves of grasses.
• It feeds by rasping plant tissues and sucking the cell contents.
• Associated mainly with Poaceae, including cereals and pastures.

3. Main hosts

• Grasses (Poaceae) in general.
• Cereals such as wheat, barley, oats and rye.
• Pastures and wild grasses.

4. Symptoms and damage

• Silvering and discoloration of the leaves due to epidermal rasping.
• Small spots and linear scars on the leaves.
• Reduced plant vigor under intense attacks.
• Potential impact on young cereals, especially under dry conditions.

5. Biological cycle

• Eggs inserted into the leaf tissues.
• Nymphs feed actively on young leaves.
• Pre-pupa and pupa in the soil or in plant debris.
• Cycle favored by moderate to high temperatures.
• Several generations per year, with greater incidence in spring and summer.

6. Monitoring

• Direct observation of symptoms and insects on the leaves.
• Regular sampling in cereals and pastures.
• Sticky traps as a complementary method.
• Reinforced monitoring during dry periods.

7. Management measures

• Cultural: crop rotation; control of wild grasses; proper stubble management.
• Preventive: sowing in periods less favorable to the pest; maintaining plant vigor.
• Biological: promotion of natural enemies present in cereal agroecosystems.
• Integrated protection: judicious application of authorized insecticides; rotation of modes of action; integration with cultural practices.

Bibliographic references

• EPPO Global Database – Anaphothrips obscurus.
• CABI – Invasive Species Compendium – Anaphothrips obscurus.
• Kirk, W. D. J. (1997). Feeding behaviour and nutritional requirements of thrips. In: Thrips as Crop Pests.
• Mound, L. A. & Teulon, D. A. J. (1995). Thysanoptera as phytophagous pests. Annual Review of Entomology.
• Vierbergen, G. (1998). Thrips species associated with cereal crops in Europe. Acta Horticulturae.