Pine beetles and ash borers around Rome

Two insects explain a lot of dead trees in northwest Georgia: the southern pine beetle in pines and the emerald ash borer in ash. Both are tracked by the Georgia Forestry Commission.

Southern pine beetle

The Forestry Commission ranks this gnat-sized beetle as the Southeast's most damaging forest insect. Its galleries girdle the tree, and it carries blue stain fungi that block the tree's water flow. It attacks all of Georgia's southern yellow pines; loblolly, shortleaf and Virginia pines are the most susceptible, and white, slash and longleaf the most resistant.

Signs

• Pitch tubes and boring dust (frass) on the bark.
• Needles turning from pale green to yellow to red, then brown.
• Drought-stressed trees may not form pitch tubes at all, so watch the needles.

Timing

Outbreaks are cyclic and tied to drought or flooding. In the Piedmont they reach epidemic levels about every 6 to 10 years, in the mountains about every 12, and an outbreak may last one to three years. The commission flies aerial surveys starting in early summer on a 5-to-10-mile grid.

What the commission advises

Fell the infested pines and either haul them out or leave them on site. Either way, also fell a strip of healthy pines ahead of the spot's advancing edge, with the strip's width no less than the height of the infested trees. The commission generally advises against insecticides.

Emerald ash borer

The emerald ash borer was found in DeKalb and Fulton counties in July 2013 during a national USDA survey. The Forestry Commission's county table now includes Floyd, along with Bartow, Chattooga, Gordon and Polk. Ash material can move freely inside Georgia but faces restrictions going to Florida and Alabama. The commission's position is that tree care should always be provided by a certified arborist, and it offers a homeowner decision guide.

When a dying tree should come down

A dead pine near a house, a drive or a play area is a candidate for prompt removal. Ask the contractor how urgent it is, and whether nearby pines in the same spot should come down as the buffer the commission describes.