Department of Parks and Recreation
Tree Pests
Got pests?
Flathead Borers
Drought stressed trees are vulnerable to flathead borers and its relative, the roundhead borer. Flathead borers are common to the United States and have been noted in Arlington this summer. With more than 150 varieties of flathead borers east of the Mississippi, you’ll find them feeding on a wide variety of trees, including oak, sycamore, walnut, poplar, elm beech, hickory, cherry and others. Most borers are considered to be a secondary pest to trees, attacking those that are already suffering from stress (such as drought). However, some types of “roundhead” borers attack healthy trees. Learn more about tree borers:
- Flathead Borers on Hardwoods - Kim D. Coder (The University of Georgia)
- Longhorned Beetles/Roundheaded Borers - Virginia Cooperative Extension (Virginia State University)
Gypsy Moths
Another pest that has evident this year is the gypsy moth. Arlington County has had extremely low levels of Gypsy Moths for the past 11 years but the entire Mid Atlantic region is currently experiencing an increase in Gypsy Moths with extensive forest defoliation resulting. Gypsy Moth egg masses are laid from late July through August. The egg masses are tan to buff colored, oval in shape, are typically 1-3 inches in length and covered with fine hairs. They 
are usually found on tree bark or on the underside of branches although the female will lay eggs in any protected location a caterpillar can crawl. Get into the habit of checking for egg masses on your outdoor equipment, on woodpiles, under house shutters, yard ornaments, planters, trailers, campers and vehicles.
If you are finding 10 or more egg masses on your property, report your findings to Julie Taylor at 703-228-7744 so that your area can be included in the County’s official egg mass survey count. Results of egg mass surveys are used to determine which areas may qualify for the state’s treatment program the following spring. Read more about Arlington County's Gypsy Moth Program.
Several informative websites about gypsy moths include:
Have Questions? Need Help?
Contact the Arlington Unit of Virginia Cooperative Extension at 703-228-6414 or ex013mg@vt.edu for information on treatment options.
