Mustard greens-Flea beetle

Includes cabbage flea beetle (Phyllotreta cruciferae)

Pest description and crop damage Flea beetle adults are metallic greenish brown to black in color and from 0.06 to 0.12 inch long. They derive their name from their well-developed hind legs; when disturbed, they jump like fleas. The larvae live in the soil, are slender, whitish, and about 0.25 inch long when mature. Adult beetles chew small holes in leaves, giving them a sievelike appearance. The cotyledons of emerging seedlings are especially susceptible to damage. The larvae feed on underground parts of the plant. High populations of flea beetles feeding on seedling plants can result in stand loss. Foliar damage to mature plants is not considered to be damaging economically. Flea beetles contribute to the spread of various plant diseases.

Biology and life history Most flea beetle species have similar life cycles. Adults overwinter in trash around field margins. They become active in late March through May. Flea beetles lay their very small eggs in May in the soil around the plant, on the leaves, or in cavities hollowed out in stems. The larvae feed on the foliage, mine the leaves, or attack the roots, depending on the species, usually from June to mid July, when pupation in the soil occurs. Adults emerge from July through early September and feed a short time before overwintering in trash around field margins. Depending on the species, there are one or two generations each year.

Pest monitoring Monitor fields for flea beetles soon after transplanting or as seedlings emerge. Flea beetles attacking the cotyledons of emerging broccoli seedlings can destroy a new planting in 24 hours.

Treat for flea beetles when small holes show on transplants or on plants from seeded fields. Young plants (three to five leaves) often withstand flea beetle injury, but they may be killed if the weather is dry and windy. The percentage of plants affected and forecasted weather conditions will indicate the need to treat.

When the flea beetles on seedlings are migrating from hosts outside of the field, most of the infestation will be localized within 200 feet of field borders. Check the distribution of leaf feeding to see if this is the case, and consider border treatments only. If high populations exist 1 to 2 weeks before harvest, and foliage is declining as a food source for the beetles, spot treat according to the flea beetle distribution.

Management-cultural control

"Trap crops" such as radish or daikon may help lure flea beetles away from the main crop. This has not been tested in the Pacific Northwest. Floating row covers or other screening can be used to exclude the beetles during seedling establishment of high-value crops. Flea beetles can be vacuumed off foliage, but this must be repeated frequently. Reinvasion of plants can be rapid.

Management-chemical control: HOME USE

  • acetamiprid
  • azadirachtin (neem oil)-Some formulations are OMRI-listed for organic use.
  • bifenthrin
  • carbaryl
  • cyfluthrin
  • imidacloprid
  • kaolin-When applied as a spray to foliage and stems it acts as a repellent to some insect pests. Some formulations are OMRI-listed for organic use.
  • lambda-cyhalothrin
  • malathion
  • permethrin
  • pyrethrins-Some formulations are OMRI-listed for organic use.
  • spinosad-Some formulations are OMRI-listed for organic use.
  • zeta-cypermethrin

Management-chemical control: COMMERCIAL USE

  • alpha-cypermethrin (Fastac EC) at 0.014 to 0.025 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.075 lb ai/a per season.
  • beta-cyfluthrin (Baythroid XL) at 0.019 to 0.025 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.1 lb ai/a per season. Toxic to bees.
  • beta-cyfluthrin/imidacloprid (Leverage 360) at 0.07 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.1 lb ai/a beta-cyfluthrin or 0.2 lb ai/a imidacloprid per season.
  • bifenthrin (Brigade 2EC) at 0.033 to 0.1 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.4 lb ai/a per season.
  • bifenthrin/imidacloprid (Brigadier) at 0.06 to 0.0.95 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Limit 5 treatments after bloom. Do not exceed 0.24 lb ai/a imidacloprid and 0.5 lb ai/a bifenthrin.
  • bifenthrin + zeta-cypermethrin (Hero) at 0.04 to 0.1 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.45 lb ai/a per season.
  • carbaryl (Sevin 4F) at 0.5 to 1 lb ai/a. PHI 14 days. REI 12 hr. Retreatment interval 7 days. Limit 4 treatments. Do not exceed 6 lb ai/a per season.
  • chlorantraniliprole/thiamethoxam (Voliam Flexi) at 0.1 to 0.172 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.172 lb ai of thiamethoxam or 0.2 lb ai of chlorantraniliprole per acre per growing season.
  • clothianidin (Belay) at 0.05 to 0.067 lb ai/a foliar, 0.15 to 0.2 lb ai/a soil. PHI 7 days foliar, 21 days soil.REI 12 hr. Retreatment interval 10 days. Do not exceed 0.2 lb ai/a per season.
  • cyantraniliprole (Exirel) at 0.088 to 0.133 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 5 days. Do not exceed 0.4 lb ai/a per year.
  • cyfluthrin (Tombstone) at 0.038 to 0.05 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.2 lb ai/a per season.
  • cyfluthrin + imidacloprid (Leverage 2.7) at 0.08 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.17 lb ai/a cyfluthrin or 0.24 lb ai/a imidacloprid per year.
  • cypermethrin (Holster) at 0.05 to 0.1 lb ai/a. PHI 1 day. REI 12 hr. Allow at least 7-days between applications. Do not exceed 0.4 lb ai/a per season.
  • dinotefuran (Venom) at 0.088 to 0.131 lb ai/a PHI 1 day. REI 12 hr. Do not exceed 0.263 lb ai/a per season.
  • malathion (Gowan Malathion 8) at 1.0 lb ai/a. PHI 7 days. REI 12 hr. Limit 3 treatments. Retreatment interval 5 days.
  • imidacloprid (Admire Pro) at 0.047 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 5 days. Do not exceed 0.23 lb ai/a foliar per season. No soil application for flea beetle.
  • imidacloprid (Provado) at 0.0475 lb ai/a. PHI 7 days. REI 12 hr. Allow 5 days between foliar sprays. Do not exceed 0.23 lb ai/a per season.
  • thiamethoxam (Actara) at 0.023 to 0.047 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.172 lb ai/a per season.
  • thiamethoxam (Platinum) at 0.078 to 0.172 lb ai/a. PHI 30 days. REI 12 hr. Do not exceed 0.172 lb ai/a per season.
  • thiamethoxam + chlorantraniliprole (Durivo) at 0.195 to 0.257 lb ai/a applied to the soil. PHI 30 days. REI 12 hr. Do not exceed 0.172 lb ai of thiamethoxam or 0.2 lb ai of chlorantraniliprole per acre per growing season.
  • zeta-cypermethrin (Mustang) at 0.028 to 0.05 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.3 lb ai/a per season.