Insect: Beetle (Coleoptera: Chrysomelidae)
ragwort flea beetle
Origin: The beetle was first found in Italy and was natively distributed in Eurasia (1). The beetle is most commonly found north of the Mediterranean to southern Scandinavia and also from eastern China to Ireland (2).
Overwintering state: Mostly larvae, but sometimes adult (1).
Egg Stage: Eggs are laid around the roots of the weed (2). They are very small, less than 1 mm in diameter, and white (1), but grow darker in color as time progresse (2).
Larval Stage: Larvae are 2 to 4 mm long (1). They hatch after about two weeks and feed on the roots (2).
Pupal Stage: Pupa are white and about 2 to 4 mm long. The larvae pupate in the soil during the spring (1).
Adult Stage: Longitarsus jacobaeae adults are 2-4 mm long and females are usually about 1 mm longer than males. They are light brown in color and their back legs are used for hopping (1,2). The adults come out in the spring, rest during the summer, and mate during the fall (1). The females can lay 1000 eggs but normally lay about 500 (2).
Damage to Host: Longitarsus jacobaeae attack the weed Senecio jacobaea, commonly known as tansy ragwort. Adults feed on the rosettes and the leaves, causing a holed appearance. The larvae eat the roots (1).
Host Impact: The beetle is a highly effective way to control the tansy ragwort. In most places where released, Longitarsus jacobaeae have been able to control the weed quite successfully.
Root feeding by the larvae have the largest impact on the plant (1).
Favorable Release Habitats: Longitarsus jacobaeae favor open pastures. They struggle in areas that are prone to flooding, have lots of shade, or are at elevations over 800 m (2,640 ft.) (1)
How and Where to Collect, Transport, and Release: The easiest stage to transport these beetles is in the adult stage in groups of 100 to 500. It is best to collect the adults in October and November. After collection, adults should be kept cool and dry and have plant material in order for survival. With these conditions they should survive for a few weeks. Also, tissue paper is necessary for the beetles to crawl on, or else they will wear themselves out too fast. The insects will bump into each other often when they are in large numbers without a sufficient amount of tissue paper (1).
How to Redistribute Once Established: The best way to redistribute is to vacuum or sweep net the adults from the rosettes and to distribute them in a climate similiar to the one they were taken from (2).
How and Where to Purchase: At the Biological Control of Weeds Pricing website, you can purchase 105 insects for $75 (3).
Remarks: In the state of California, the ragwort flea beetle has been very successful in diminishing the tansy ragwort weed. The insect has almost completely stopped the weeds from flowering in many places (1).
1. Lethbridge Research Centre Established Biocontrol Agent
2. Systematic Names - Longitarsus jacobaeae
3. Biological Control of Ragwort in Victoria
4. Tansy Ragwort in British Columbia
5. Noxious Weed IVM Guide - Tansy Ragwort
6. Biocontrol Agents of Tansy Ragwort
7. Biological Control of Weeds Pricing
8. Measuring the Consumption Rates of Longitarsus jacobaeae
9. Biocontrol of Ragwort
10. Hiking with Chelle in Tansy Ragwort
1.) Rees, Normanl, et. al., Ed., Biological Control of Weeds in the West, Western Society of Weeds Science, in Cooperation With USDA ARS, MT Department of Ag, and MT State Univ., Color World Printers, Bozeman MT, Feb., 1996.
2.) Harris, P. Lethbridge Research Centre Established Biocontrol Agent. [Online] Available: http://res2.agr.ca/lethbridge/weedbio/agents/alongflv.htm Last modified December 28, 2000
3.) Biological Control of Weeds, Inc., 1418 Maple Drive, Bozeman, MT 59715. Phone: 406-586-5111. Fax: 406-586-1679. Email: email@example.com [Online] Available:
By: Anna Marx 1/14/02
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