Black leafy spurge flea beetle (Aphthona czwalinae)

Biocontrol Agent Factsheet

Black leafy spurge flea beetles are biocontrol agents for the invasive weed leafy spurge. Adults feed on leafy spurge top-growth but the main damage to the plant is from larvae feeding on the roots. 

Overview

Pests Targeted: Leafy spurge
Pest Stage: Roots (primary, fed on by larvae); some damage to foliage from adults
Commercially Available? No
Scientific Name: Aphthona czwalinae
Biocontrol Agent Type: Weed-feeder

Close-up photo of a black colored flea beetle with black rear legs crawling on a plant stem.
Adult Aphthona czwalinae or black leafy spurge flea beetle. Photo credit: L.L. Berry, Bugwood.org

Common Names

Black leafy spurge flea beetle

Relative effectiveness

Black leafy spurge flea beetles (Aphthona czwalinae) like A. lacertosa is more widely adapted to varying soil types than A. nigriscutis and A. cyparrissiae. A. czwalinae does well in both sandy loam and heavy clay soils.  Both A. czwalinae and A. lacertosa tolerate shady areas. A. czwalinae appears to establish better in tall grass areas than other Aphthona spp. used for leafy spurge biocontrol. 

Where to use

Pasture or rangeland
Areas with well-drained soil and only moderate densities of leafy spurge (see more)

About Aphthona czwalinae

Black leafy spurge flea beetle adults feed on leafy spurge top-growth but the main damage to the plant is from larvae feeding on the roots. Larvae overwinter in the soil, pupate and emerge from the soil in early summer. The adult females lay eggs on the soil surface and larvae hatch in about 8 days.  The larvae then move to the fine feeder roots of leafy spurge. They go through three instars before beginning to feed on root buds. There is one generation per year.

  • Native/Non-native: Non-native
  • Preferred climate: arid
  • Region: Generally, most productive in the Northern Great Plains of the US and Canada.
  • Established: Yes
  • Where established: North Central Great Plains and adjacent Rocky Mountain regions of US and Canada.

Aphthona czwalinae Appearance

Adult black leafy spurge flea beetles are 2.5 to 3.5 mm in length and black in color. They generally have black rear legs, but the color sometimes varies to brown making these insects very difficult to distinguish from other species of flea beetles in the same genus (e.g., A. lacertosa). Adults typically hop when disturbed but are capable of flight. Larvae are 1-6 mm long, with short legs, yellow heads, and creamy-white bodies.

Mixed population of adult A. lacertosa and czwalinae feeding on leafy spurge topgrowth. While a source of food for the adults this type of feeding has no effect on long-term leafy spurge control. Photo credit: Rodney G. Lym

Numerous black flea beetles feeding on leafy spurge leaves.
Mixed population of adult A. lacertosa and czwalinae feeding on leafy spurge topgrowth. While a source of food for the adults this type of feeding has no effect on long-term leafy spurge control. Photo: Rodney G. Lym
Black beetle with beaded antennae climbing up a narrow leaf

Adult Aphthona czwalinae or black leafy spurge flea beetle.

Large white colored Aphthona larvae laying on soil.

Large white colored Aphthona larvae laying on soil.

Cross-section of plant root showing feeding holes from Aphthona larvae.

Aphthona larvae feed on leafy spurge roots. The first instar feeds on fine feeder roots while the third and final instar feeds on and destroys leafy spurge root buds which greatly reduce weed density the following season.

Life Cycle

General Aphthona spp. flea beetle life cycle. All species except Aphthona adominalis have one generation per year and over winter as larvae in the soil.

Diagram of the life cycle of Aphthona flea beetles. Adult Aphthona flea beetle adults feed on leafy spurge topgrowth from June through August. They lay eggs on the soil surface and larvae feed on the roots in the fall. Larvae pupate in the spring and emerge as adults to repeat the cycle.
General Aphthona spp. flea beetle life cycle. All species except Aphthona adominalis have one generation per year and over winter as larvae in the soil.

How to Use Aphthona czwalinae

Biocontrol category: Classical - released once and persists

When to use: Before moving black leafy spurge flea beetles, you should confirm with your local regulatory agency that this is permitted. Flea beetles should be collected as adults from established stands and moved to establish new populations. The “nursery” area should be monitored from late-June through mid-July when adults emerge from the soil and begin feeding on leafy spurge topgrowth. The best time to collect flea beetles for redistribution is from 10 AM to 3 PM when the air temperature is greater than 70 F, there is little or no wind, and the skies are generally sunny. Leafy spurge should be dry before collecting flea beetles because wet conditions will make sweeping difficult and reduces the adult survival during transportation.

Rate: Several hundred to 1000 adult black leafy spurge flea beetles should be released per spot as a group rather than spreading them thinly through the leafy spurge infestation. Flea beetles establish best in moderate densities of leafy spurge (60 to 90 stems per square yard) with minimal grass cover and thatch. Establishment in dense leafy spurge stands is often difficult. Release flea beetles on the margins of dense infestations and allow the insect to work into denser stands as the population builds.

Maximizing effectiveness: Once collected, the flea beetles should be transported in paper bags or containers. Do not use plastic containers because moisture condensing on the plastic can drown the insects. Add some leafy spurge to the container and place in a cooler containing ice or ice packs. Do not allow the containers or cooler to sit in the sun. Flea beetles should be released as soon as possible after collection. Releasing the same day as collection is ideal; however, insects can survive several days when refrigerated at 40 to 45 F. The more similar collection and release environments are, the sooner the flea beetles are likely to become established and begin to control leafy spurge.

Pest stage: Larvae of the black leafy spurge flea beetle feed on leafy spurge roots from the time eggs are laid and hatched in mid-summer until near soil freeze-up in mid-October. It is this feeding that assists with control of leafy spurge. Adults may also feed on leafy spurge foliage, but the damage from this feeding is minor in comparison.

Mode of action: Weed-feeder

Compatibility: Several options are available for leafy spurge control besides biological control agents, including the use of herbicides, grazing, seeding competitive grasses, and cultivation. Before beginning a leafy spurge control program, consider the best options suited for the situation and utilize more than one. Most successful control programs have used multiple control methods combined over several years. 

Commercially available: No

(Any time you use a pesticide, you must read and follow the label directions and comply with all applicable laws and regulations related to pesticide use. Also be sure that any pesticide used is approved for use in your country and state/province.)

About Leafy spurge (Euphorbia esula L.)

Leafy spurge (Euphorbia esula L.) is a long-lived perennial weed that spreads by both root and seed. The weed invades rangeland, wildlands, roadsides and cropland. The plant grows 2 to 3 feet tall, has linear shaped blue-green leaves, and contains a white milky latex throughout the top growth. Leafy spurge produces a flat top cluster of yellow bracts that surround the inconspicuous true flower.

Leafy spurge Damage

Leafy spurge replaces other plants (including native species) resulting in negative impacts on many species within the ecosystem. The presence of leafy spurge in pastures or rangelands also reduces the suitability of land for grazing domesticated animals like cattle and horses. They avoid eating the plants because the latex they produce contains a toxic compound.

Plant with narrow leaves and small yellow flowers.

Leafy spurge in flowering growth stage.

Field full of leafy spurge plants

Leafy spurge can become a near monoculture in the pastures and rangeland of the Northern Great Plains.

Consult the following extension publications for more detailed information concerning biological control of leafy spurge:

Author

Rodney G. Lym
Professor emeritus, North Dakota State University

Date: November 2021

  • Adult Aphthona czwalinae or black leafy spurge flea beetle. Photo credit: L.L. Berry, Bugwood.org
  • Mixed population of adult A. lacertosa and czwalinae feeding on leafy spurge topgrowth. While a source of food for the adults this type of feeding has no effect on long-term leafy spurge control. Photo credit: Rodney G. Lym
  • Adult black leafy spurge beetle. Photo credit: USDA APHIS PPQ - Bozeman Biocontrol Station , USDA APHIS PPQ, Bugwood.org
  • Third instar Aphthona larvae which will pupate and overwinter in the soil. Photo: Rodney G. Lym
  • General Aphthona spp. flea beetle life cycle. All species except Aphthona adominalis have one generation per year and over winter as larvae in the soil. Credit Rodney G. Lym
  • Aphthona larvae feed on leafy spurge roots. The first instar feeds on fine feeder roots while the third and final instar feeds on and destroys leafy spurge root buds which greatly reduce weed density the following season. Photo: Rodney G. Lym
  • Leafy spurge in flowering growth stage. Photo credit: John M. Randall, The Nature Conservancy, Bugwood.org
  • Leafy spurge can become a near monoculture in the pastures and rangeland of the Northern Great Plains. Photo credit: Rodney G. Lym

Related Links

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NYS Integrated Pest Management

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