Aphthona lacertosa

Description

Aphthona lacertosa is a root-feeding flea beetle of the genus Aphthona. It is one of 5 Aphthona spp. that has been used in Alberta, Canada to control leafy spurge, an invasive plant that reduces pasture quality and degrades natural habitats. A. lacertosa is native to Eurasia, but was released into North America first in 1990, then more widely in 1997. A. lacertosa was released specifically to control leafy spurge in wet habitats, where the use of herbicides is restricted and other previous biocontrol efforts had proven ineffective. It has established in Manitoba, Saskatchewan, and Alberta. Adults of this species are black and indistinguishable from A. czwalinae in the field. Larvae cause the most damage to the plant by feeding on the roots. In one study, beetle success in controlling leafy spurge was related to the temperature degree days at the control site, with sites with more temperature degree days having more success. Aphthona is a genus of beetle, in the leaf beetle family Chrysomelidae, native to Europe and Asia. More specifically, Aphthona are flea beetles, meaning they have enlarged hind legs for jumping away from potential danger. There are some 300 species known worldwide. This flea beetle genus is important because of the usefulness of some species in controlling leafy spurge, a major invasive weed in parts of western North America. Several Aphthona species have been taken from Europe and introduced into localized areas of the United States and Canada, and some success against the weed is being seen. The six species used for this purpose include A. abdominalis, A. cyparissiae, A. czwalinae, A. flava, A. nigriscutis, and A. lacertosa, though A. abdominalis apparently never established a viable population and was never introduced in Canada. Control is generally thought to be effective, but results vary from site to site, which has been attributed to soilborne pathogens, phenology of spring, soil texture, and leafy spurge density. Control is less effective in sandy soils. Control may not be reliably observed and measured for 10 years or more.