Biology and identification of the tarnished plant bug in field crops

The European tarnished plant bug is a capsid bug that can damage several crops including carrot, celery, lettuce and sugar beet, reducing marketability. It is also a problem in some soft fruit crops (e.g. strawberry and blackberry). 

• The presence of alternative hosts in nearby fields or field margins may increase risk 
• Damage may be more severe on headlands, owing to adults overwintering in hedgerows 

Scientific name: Lygus rugulipennis 

Adult bugs are 5–6 mm long, oval–shaped and brownish–green with dark markings. They usually appear to be ‘tarnished’. They have a small head with a pair of long, jointed antennae.  

Eggs are elongate and slightly curved. The nymph is green with black spots on its thorax. 

Sep–Feb: Adults overwinter on evergreen foliage and in leaf litter. 

Mar–May: Adults emerge in March/April and feed on plant tissues. Small brown spots appear on young leaves and the area surrounding each feeding site dies. Affected plants may fail to grow properly and plant parts become malformed. 

May: Females lay eggs in plant tissue (terminal shoots, buds, and fruits). 

Jun–Jul: Nymphs feed on plant tissues and develop through six instars. Adults develop by July and continue to reproduce. 

Aug–Sep: Another generation is produced in August/September. 

In summer, other species of capsid bugs feed on the leaf veins of older plants, causing puckering and yellowing. Close to the puncture site, the tissue is often blackened.  

Non-chemical control 

Trap crops have been used successfully in strawberry, sometimes in conjunction with vacuuming the trap crop to reduce infestations. Such approaches for field vegetables have not been evaluated.  

Some years ago, some variation in susceptibility was identified between carrot cultivars.  

Monitoring 

Pheromone traps are available to monitor adult tarnished plant bugs.  

Blue sticky traps are more effective than yellow sticky traps.  

Thresholds 

None established.  

Insecticide resistance 

None known.