Ragwort
Guides
Longitarsus jacobaeae
Ragwort Flea Beetle, Tansy Ragwort Flea Beetle
Longitarsus jacobaeae is a flea beetle (Chrysomelidae) native to Europe, widely introduced as a biological control agent for tansy ragwort (Senecio jacobaea), a toxic weed affecting livestock. Adults and larvae feed on ragwort foliage, with larvae mining roots and crown tissue. The species exhibits pronounced seasonal behavioral patterns, including summer aestivation and winter inactivity. It has established successfully in North America, Australia, and New Zealand.