- Adult flea beetles cause distinctive ‘pitting’ in leaf surfaces. This type of damage is easily recognizable.
- Beetles are small (most <1/4″) and have enlarged femurs on their back legs. This allows them to jump very far, hence the common name. The ‘thickened thighs’ can be used as an identification tool.
- Some of the common flea beetles we have here in the PNW are
Phyllotreta cruciferae, crucifer flea beetle : metallic blue-green to black
Phyllotreta striolata, striped flea beetle: black with wide, wavy yellow stripes on wing covers
Psylliodes punctulata, hop flea beetle, sometimes called radish flea beetle: shiny black or green with brown legs
- The above species feed on brassica crops and cruciferous weedy hosts like yellow rocket, shephard’s purse and wild mustard. Common lambsquarters is also preferred
- Activity increases with warming temperatures, and invasion into fields can be rapid.
- Newly seeded crops are particularly vulnerable, damage to cotyledons can cause uneven stands or crop loss.
- Transplants with 3+ leaves can withstand more damage but should still be monitored closely.
- Treatment on cole crops is recommended when 10-20% of a stand shows feeding damage.
- Spot or border treatments can be effective. Consult the PNW Insect Management Handbook for labeled products.