• Adult flea beetles cause distinctive ‘pitting’ in upper 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, the damage to cotyledons can cause uneven stands or crop loss.
• Larvae of most species feed on roots.
• Petiole clipping can occur.
• Treatment threshold varies by crop (more info coming soon), but to estimate feeding damage, here is a handy graphic (credit Soroka and Underwood, Agriculture and Agri-Food Canada).
• Spot or border treatments can be effective. Consult the PNW Insect Management Handbook for labeled products.