Melon thrips

Thrips palmi

1. Identification

• Common name: Melon thrips
• Scientific name: Thrips palmi Karny
• Order: Thysanoptera
• Family: Thripidae

2. Pest description

• Small-sized thrips species (approx. 1 mm), with a narrow body and yellow to pale-yellow coloration.
• Pale nymphs, generally present on young leaves, flowers and fruits.
• It feeds by rasping plant tissues and sucking the cell contents.
• Highly polyphagous pest, of great economic importance on vegetables and ornamentals.
• Virus vector, including the Groundnut Bud Necrosis Virus (GBNV).

3. Main hosts

• Cucurbits (melon, cantaloupe, cucumber, squash).
• Solanaceae (pepper, eggplant).
• Various ornamentals.
• Wild plants that act as a reservoir.

4. Symptoms and damage

• Silvering and discoloration of the leaves due to epidermal rasping.
• Deformations on young leaves and flowers.
• Scars, blemishes and a “russeting” appearance on fruits, reducing commercial value.
• Severe damage under hot and dry conditions.
• Possible virus transmission, aggravating the economic impact.

5. Biological cycle

• Eggs inserted into the plant tissues.
• Nymphs feed actively on young leaves, flowers and fruits.
• Pre-pupa and pupa in the soil or in plant debris.
• Very fast cycle in hot environments, allowing multiple generations per year.
• High capacity for dispersal and colonization, especially in greenhouses.

6. Monitoring

• Direct observation of symptoms and insects on young leaves, flowers and fruits.
• Blue or yellow sticky traps for detection and counting.
• Regular sampling in sensitive crops, especially cucurbits.
• Reinforced monitoring during dry and hot periods.

7. Management measures

• Cultural: removal of plant residues; control of wild plants; adequate ventilation in greenhouses.
• Preventive: use of pest-free plants; insect-proof nets; strict cultural hygiene.
• Biological: release of predatory mites (Amblyseius swirskii, A. cucumeris) and predatory bugs (Orius spp.).
• Integrated protection: judicious application of authorized insecticides; rotation of modes of action; integration with biological control.

Bibliographic references

• EPPO Global Database – Thrips palmi
• CABI – Invasive Species Compendium – Thrips palmi
• 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.
• Seal, D. R. (1997). Thrips palmi: an emerging pest of vegetables and ornamentals. Florida Entomologist.