Chrysomdidae: Coleoptera,
beetle, flea beetle (1-3)
Biological Weed Control Links Photos: Apthona sp. Larva
Photo by Bob Richard, USDA-APHIS-PPQ.Common Name: Black leafy spurge flea beetle (2,3)
Origin: The original source of this species is in Europe around Hungary. It's found in Eastern to central Europe, central Asia, Eastern Siberia, and in limited cases, Eastern Austria and Northwestern Hungary. (2,3)
Life Cycle:
Egg Stage: The eggs are inserted into the soil next to leafy spurge stems. This usually is done during June and July. The eggs are oval, look yellow in color, and measure about .7 by .4 millimeters. The eggs will hatch in about 16-17 days.
Larval Stage: The larval stage has three instars. The larvae are thin and white except for the head that is brown. They start eating the leafy spurge by digging themselves into the ground and feeding on the roots. They do this until cold soil temperatures come in the late fall.
Pupa Stage: They then spend time in a soil cell in the ground during the pupa stage. The time spent in the soil cell is usually from late spring to early summer. From mid June to July, the adults come out of their soil cells and can be found on the leafy spurge plants above the ground.
Adult Stage: Adults are beetles that are black and have a yellowish color on their legs (upper and middle), while the back legs are all black. Males measure 2.9 mm in length, and females are 3.1 mm. (1-3).
Type of Damage: The adults and the larvae are the stages in which damage is done to the leafy spurge. The adults eat the leaves and flowers. They create holes in the foliage that reduces photosynthesis and sugar (food for the plant) that goes to the roots. The larvae eat the root hairs which reduces the amount of moisture taken in by the roots. The larvae do the most damage to the plant. (2,3) The species which Aphthona czwalinae attack is the species Euphorbia esula and some other types of leafy spurge. They do not feed on Euphorbia pulcherrima or any other native (North American) plants. (1)
Host Impact: Modest feeding on the leafy spurge can reduce the height it grows to and make the flowering period later. Concentrated feeding can decrease stem density, lessen their height or kill the plant. (2,3)
Release Habitat: Habitat needed for this species are moist areas with high humidity and areas with vegetation, that is fertile. It can also be in areas with dry summers in a Mediterranean climate and sun exposed sites of sand or rock. Habitat bad for this species is compact clay soil, and sites with many ants in the area. (2,3)
Collection, Transportation, and Redistribution: Collect the adult beetles using sweep nets when they are out on the plants during June and July. They can stand several days with fresh leaves or longer periods under cool conditions. With longer periods you should allow them to feed on leafy spurge foliage in warmth and exercise sometimes in order to transport them. Keeping them inside during the winter or during colder temperatures can be done as long as you leave them fresh leafy spurge leaves. Over a long time however, transportation can lessen the egg distribution the insects will leave in the soil. To release the insects simple sprinkle them from jars on leafy spurge leaves, or swing your arm with the container open to let them out. Use this method to distribute to other sites of leafy spurge infestation after the original control site has been established. They like to stay together, so do not spread one release out very far (10 meters or less). (2,3)
Purchase: In a lot of states biological control sites with Aphthona czwalinae and Aphthona lacertosa already exist, and you can get these insects from the state weed management agencies, or in Montana they can be purchased from the Biological Control of Weeds, Inc. http://www.bio-control.com/ . (1).
Remarks: This species usually assemble together for mating, egg laying, and eating by using chemical scent signals called pheromones. The other flea beetles that eat of leafy spurge usually do the same behavior. There are only two black flea beetles allowed in the U.S., and this is one of them. (2,3)
Links:
Apthona sp. Larva
Infestation
fact sheets
czwalinae in general
Flea beetle
Feeding
Adult stages
Life cycle
Soil count
leafy spurge predator
Bibliography:
1) Hansen, Rich. Aphthona czwalinae. [Online] Available http://www.nysaes.cornell.edu/ent/biocontrol/weedfeeders/a.czwalinae.html, August 13, 1999.
2) Unknown author, Aphthona czwalinae. [Online] Available. http://users.aol.com/prideedu/czwalina.html, August 13,1999.
3) Unknown author, Aphthona czwalinae. [Online] Available: http://www.mcn.net/~rosebudweed/black.html, August 13, 1999.
By: Neal Bell Published By: Will Sears Updated by: Trista Zink 3/17/05.
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