Striped flea beetle (Phyllotreta striolata)

Striped flea beetle biology & life cycle

Adults overwinter in leaf litter along shelterbelts or fencerows. They emerge in mid-April to late May and begin feeding on early emerging crucifers (weeds or volunteers). Adults move to emerging cruciferous crops and feed on cotyledons and first leaves. Females lay eggs at the soil surface and larvae feed on root material of the developing plant. An earthen cell is formed for pupation. Adults emerge from the soil and feed on leaves or pods of hosts and then overwinter. One generation is produced each year. Overwintered adults cause the most damage to young canola seedlings in the spring. Adults chew holes in the cotyledons or epidermis of young leaves.

There are behavioural differences that can help distinguish striped flea beetles from crucifer flea beetles. Striped flea beetles:

• Emerge as adults 5–11 days after spring thaw begins
• Appear 1–4 weeks earlier than crucifer flea beetles
• Are less susceptible to current seed treatment control options
• Favour stem feeding

Identifying Striped flea beetle

Striped flea beetle: larvae

2-4 mm long, white with brown heads.

Striped flea beetle: Pupae

2-4 mm long, white.

Striped flea beetle: adult

The adult striped flea beetle is 2-3 mm long, oval two distinct yellow lines on back an enlarged hind femur.

Striped flea beetle: management

Why can striped flea beetles be so harmful to a canola crop?
• They emerge earlier than crucifer flea beetles, and consume more plant material.
• In adverse weather conditions, they continue to feed on the underside of leaves and stems.
• The damage they cause is less visible initially, allowing them to reach threshold before you realize they’re eating away at your crop’s profit potential.

Monitoring is important during the seedling stage of canola and "shot-hole" damage is a good indication of the presence of adults. Agronomic practices such as crop rotations will promote good stand establishment and rapid seedling growth will reduce the impact of flea beetles on canola yield. Optimizing seeding depth will also aid in fast emergence and growth and compensate for feeding damage early in the spring.

Source: Canola Council

Reported flea beetle pressure in 2021

Source: AgCall, 2021
Heat map indicates relative reports of crucifer and/or striped flea beetle pressure. The absence of any colour does not necessarily indicate absence of pests or lack of pest pressure.

Performance evaluations are based on internal trials, field observations and/or public information. Data from multiple locations and years should be consulted whenever possible. Individual results may vary depending on local growing, soil and weather conditions.