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Chamaesphecia hungarica
(Lepidoptera: Sesiidae)

by Rich Hansen, USDA-APHIS-PPQ, Forestry Sciences Lab, Montana State University, Bozeman, MT 59717-0278.

Leafy spurge is an Eurasian perennial that was introduced into North America in the 19th century. It infests several million hectares of rangelands and riparian areas in the United States and is a serious pest across the northern Great Plains where it displaces desirable grasses and forbs normally consumed by foraging cattle. Cattle and horses usually avoid leafy spurge, but should they eat it, its milky latex may cause sickness and even death. Annual direct and indirect economic losses due to leafy spurge infestation in Montana, South Dakota, North Dakota, and Wyoming are estimated to exceed $120 million. In addition, leafy spurge forms monocultures that often displace native plants and degrade wildlife habitats.

Leafy spurge has a number of biological characteristics that have caused it to be difficult to control with herbicides, and infestations generally occur in remote areas consisting of comparatively low-value land. Thus, classical biological control is envisioned as a potentially valuable spurge management tool in North America. To date, ten Eurasian insect species have been released as biocontrol agents of leafy spurge.

Chamaespecia hungarica was originally approved for introduction into the United States in 1993. It has been released at several leafy spurge-infested sites in Montana and North Dakota.

Appearance

The adult moth is 10-14 mm in length, and generally dark brown with yellow markings. The wings are mostly clear, with dark margins and brown and yellow markings. Antennae are about half as long as the body and dark; the legs are yellow with brown markings. C. hungarica larvae are found in leafy spurge roots. They are typical caterpillars reaching up to 15 mm in length; the body is generally white or somewhat yellowish in color.

Habitat

Leafy spurge-infested grasslands.

Pests attacked

The host range of C. hungarica appears restricted to plants in the subgenus Esula of the genus Euphorbia. In Europe, this beetle feeds on leafy spurge and several other closely-related spurge species. There are a few native Euphorbia spp. in the U.S. that could potentially be hosts for C. hungarica, though no feeding has yet been documented under field conditions. C. hungarica will not feed on poinsettia (Euphorbia pulcherrima), and crop species and native plants outside the genus Euphorbia will not be attacked.

Life cycle

Life cycle information is based on observations in the insect's native European habitats; little information on the biology of C. hungarica under North American field conditions is available.

Adult moths are present in early to mid-summer. After mating, females lay single eggs on leafy spurge stems, leaves, and flowers; generally, 100-200 eggs are laid by each female. Newly-hatched larvae bore into a spurge stem and tunnel down the stem into the roots. Larvae feed within the roots, overwinter, and resume development the following spring. In late spring, the mature caterpillar tunnels up inside a leafy spurge stem until slightly above the soil surface, chews an exit hole, and pupates within the stem. The newly-emerged adult moth then crawls out through the exit hole. There is one generation per year in central Europe.

Relative effectiveness

In time, this species may be a useful biological control agent because it is a root feeder and because, unlike other available biocontrol agents, it may be adapted to moist and shaded habitats. However, information on its survival and host impacts under U.S. field conditions is not yet available.

Pesticide susceptibility

Not known

Conservation

For general information about conservation of natural enemies, see Conservation in the Tutorial section on this site, or the Feature Article on conservation in the Midwest Biological Control News.

Commercial availability

Chamaesphecia hungarica is not yet available from public or commercial sources.

References

Gassman, A, and Tosevski, I. (1994) Biology and host specificity of Chamaesphecia hungarica and Ch. astatiformis (Lep.: Sesiidae), two candidates for the biological control of leafy spurge, Euphorbia esula (Euphorbiaceae) in North America. Entomophaga 39: 237-245.

Gassman, A., Tosevski, I. , and Harris, P. 1991) Chamaesphecia hungarica (Tomala) (Lepidoptera: Sesiidae): a suitable agent for the biological control of leafy spurge (Euphorbia esula L.) (Euphorbiaceae) in North America. Final report. International Institute of Biological Control, Del‚mont, Switzerland. 35 pp.

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