Grow It Eat It: Maryland's Food Gardening Network

Top Insect Pests - Flea Beetle

Flea beetle - Family Chrysomelidae, Subfamily -  Alticinae
(click on image to enlarge)

flea beetle adult cluster of fleabeetles flea beetle damage on eggplant
Flea beetle adult Cluster of flea beetle adults
 Flea beetle damage on eggplant
floating row cover wood ash
Control: Floating row cover Control: Wood ash
 
Appearance There are many species of flea beetles, which are a distinctive subfamily of leaf beetles.
Eggs: Minute, white, laid in the soil.
Larvae: Tiny white grubs.
Adults:  Shiny black or brown, some with white or yellow stripes, 1/10" oval-shaped beetles that jump when disturbed.  Pale-striped flea beetle is twice the size of others.
Life Cycle/Habits Adults overwinter in plant debris.  One of the earliest emerging insects, the adults emerge in late April to early May, mate, and  lay eggs in soil. The larvae of many species feed below the soil on plant roots, while larvae of other species and all adults chew tiny holes in leaves, creating a shot-hole effect.  Adults jump away when disturbed, much like fleas. Populations are high after mild winters. Prefer hot, dry spring weather.  One or two generations a year.
Host Plants Eggplant, corn and cabbage family (i.e. cabbage, broccoli, and cauliflower) are very susceptible. Flea beetles also feed on tomato, potato, pepper, beet, spinach, turnip, radish, plus almost every other vegetable to some degree.
Signs/Symptoms Adult feeding riddles leaves with small feeding holes that create a shot-hole effect.  Tender seedlings may be particularly targeted.  When foliage is disturbed, tiny beetles jump off in all directions. Larvae feeding on roots can lower yields. Larval feeding on sweet potato skins and shallow tunneling on tubers can ruin sweet potatoes. Adults can transmit viral or bacterial diseases.
Monitoring Watch for the characteristic shot-hole feeding pattern on leaves, particularly on the more susceptible young seedlings. This pest will ravage eggplant. Tiny black jumping beetles are easily noted.
Prevention/Control
  1. Clean up and remove garden debris to reduce overwintering sites for the beetles.
  2. Try covering vulnerable plants with a floating row cover, being sure to secure the material to the ground. For eggplant, drape the row cover over hoops - don't let the material lay directly on plants.
  3. Spray "Surround", a repellent made from kaolin clay mixed with water. It creates a particle barrier after drying that inhibits flea beetles and greatly reduces feeding. It must be re-applied after rainfall.
  4. For severe infestations spray your plants with an "organic" insecticide- pyrethrum, neem, or spinosad. You can also dust plants with diatomaceous earth.
  5. Lightly tilling your garden in spring or fall may also help reduce flea beetle populations.
Eggplant Extras:
Flea beetles can ravage young eggplant plants, leading to low yields of small fruit. It is critical to protect newly transplanted eggplant from flea beetles. Healthy, fast-growing plants are more likely to outgrow light flea beetle feeding. Some tips for accomplishing this are as follows: cover the soil with black plastic mulch one month prior to planting, set plants out two weeks after all danger of frost, plant in fertile soil high in organic matter, water regularly and fertilize every 3-4 weeks, if necessary. Protect eggplant with floating row cover until plants start to flower.

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For more information, contact Jon Traunfeld

Last updated: 01/23/2012