Basic biology and management of pea thrips

Pea thrips attack pea crops during and after flowering, causing damage to the pods. 

• Periods of slow growth in cold, dry springs, especially on stony soils, increase risk 
• In good conditions, crops usually tolerate damage and grow away 

Scientific name: Kakothrips pisivorus 

Adult pea thrips and field thrips are indistinguishable without microscopic examination. They are dark, shiny, and narrow-bodied and reach about 2 mm in length. Two pairs of wings, usually folded along the back, are used to migrate large distances.  

Eggs are minute, kidney-shaped and are embedded into the tissues of flowers and pods. The immature stages are similar in shape to the adults but have no wings and are bright yellow with a conspicuous black tip at the rear end. 

Aug–Apr: Nymphs overwinter in soil. 

May: Nymphs pupate. 

May–Jun: Winged adults emerge and move into crops. Eggs are laid in flowers and on pods. Hatching nymphs feed on the crop. Populations peak mid-June. 

Jul: Nymphs descend into soil. 

Compared with field thrips, pea thrips attack later in the season and cause distinctive silvery blemishes on the surfaces of pea pods. 

Non-chemical control 

In high-risk areas, sow late-emerging crops.  

Thrips are predated by spiders, ladybirds, predatory flies, and lacewings. 

Monitoring 

Make frequent examinations of the crop, especially after the start of flowering until pods are full.  

Thresholds 

Treatment is justified as soon as damage is seen.  

Insecticide resistance 

There is no evidence of resistance in this species.