It seems like every year an exotic, uninvited guest appears somewhere in the United States and creates new problems for our landscapes. In our area, 2001 was one of those xenophobic years. The story begins with an observant homeowner in Fairfax, VA, who noticed a voracious caterpillar munching her ornamental euonymus in the front yard. In May 2002 she collected caterpillars and sent them to Eric Day at the Insect Identification Laboratory in Blacksburg, VA. Eric reared the larvae and sent these unknown moths to specialist John Brown at the Systematic Entomology Laboratory, USDA. Dr. Brown identified the moth as one not known to occur in the US - a new, exotic, invader. The scientific name of this moth is Pryeria sinica. Prior to its discovery in Fairfax, this pest was only known to occur throughout the Palearctic, or old world region, from eastern Russia and China through Korea, Japan and Taiwan.
In Northern Virginia more moths were collected in 2003. News of this find spread throughout the entomological community. The bug geeks had their antennae up, and on May 28, 2003, Shawn Johnson of Glen Burnie arrived at the Maryland Department of Agriculture with a bucket of bugs. Gaye Williams of the section's Entomology Laboratory instantly recognized these as the newly arrived euonymus leaf notcher.
Eunonymus Leaf Notcher caterpillars (Pryeria sinica)
The scientific literature from Asia and observations made in the United States provide a sound knowledge of the life cycle of this pest. Pryeria sinica spends the winter as taupe-colored eggs deposited in clusters or 150 or more on pencil-sized twigs near branch terminals. In Asia, eggs have also been found on leaves. Female moths deposit eggs from October through December. Eggs hatch in the early spring, usually in late March and early April. Unlike many moths, these are day fliers. They have unique patterns and colors on their body and wings that make them closely resemble wasps. The fact that they mimic wasps may help them avoid being eaten by day-feeding predators such as birds. The adults bear patches of black and orange scales on their bodies, and their wings are largely clear except for patches of light yellow scales at the base of the wings. The larvae are gregarious and are often found in large clusters. Their background body color is white, and several black longitudinal stripes run the length of their bodies.
The type of damage caused by the feeding of this caterpillar includes marginal notches and coarsely shredded leaves. When abundant, these caterpillars can entirely strip large areas of shrubs. So far in North America, this pest has been reported on Euonymus japonicus and E. kiautschovicus 'Manhattan'. In its native range in Asia, the euonymus leaf notcher has been reported feeding on E. sieboldianus, E. japonicus and E. alatus. Moreover, other members of the Celastraceae family such asCelastrus punctatus and C. orbiculatus (Oriental bittersweet) are also recorded as hosts for this pest.
This pest has two obvious weak points that provide excellent opportunities for management. From the time that egg laying ends in December until the eggs hatch in spring, eggs can be crushed on the plant or simply pruned and removed. If larvae are small or in restricted areas on a plant, then they too may be removed by a gloved hand or pruner. If larvae are widely distributed, abundant or otherwise difficult to control manually, then several insecticides should perform well in controlling this pest. Some of the most "environmentally friendly" insecticides for killing caterpillars contain Bacillus thuringiensis kurstaki . These insecticides kill the cells in the gut of the caterpillar - a slow and painful death to be sure.
Euonymus leaf notcher, where are you now? No one knows for sure the extent of the leaf notcher infestation. Both the State of Virginia and the State of Maryland have done surveys to delimit the extent of the infestation. Here is what is known. Surveys in Maryland in 2003 and 2004 revealed more than 30 locations where the caterpillars are established. The moth occupies a triangular zone from Glen Burnie at the northern apex to Severna Park at the east and Millersville at the west. In Virginia the beast has been found at two locations near Fairfax City separated by about 1.5 miles.
If you find the euonymus leaf notcher or suspect that you have, contact either Mike Raupp, mraupp@umd.edu, 301-405-8478, or Dick Bean, Maryland Department of Agriculture, dick.bean@maryland.gov, 410-841-5920 for finds in Maryland. In Virginia, contact Eric Day, idlab@vt.edu , 540-231-4899. You can also contact your friends at the Virginia State Department of Agriculture or the Cooperative Extension Service in your county.
References
For more information on the euonymus leaf notcher, visit:
http://everest.ento.vt.edu/~idlab/newmoth/newmoth.htm
http://www.mdinvasivesp.org/pryeria_sinica.html