Keeping an eye out for the ambrosia beetle

Published 7:05 pm Friday, February 16, 2018

Have you noticed walking in yard or woods tooth pick projections on the bark of trees?

It’s pretty unusual looking. These strands of boring dust can protrude one and one-half inches from the bark. The female adult Granualate Ambroshia Beetle is the culprit.

Introduced into South Carolina from Asia in the 1970s, these beetles have since spread through the southeast, the gulf coast states and as far north as Maryland. This tiny beetle feasts on dogwoods, redbuds, maples, ornamental cherry, Japanese maples and crepe myrtles. Other reported hosts may be pecans, peaches, plums, persimmons, golden rain trees, Chinese elms, magnolias, figs and azalea. They tend to prefer thin barked, deciduous trees.

These tiny, blackish, brown beetles resemble the Southern Pine Beetle. Their damage is similar. The adult female bores into the heartwood to build galleries for her eggs. These tunnels are conduits for pathogens.

The ambrosia fungus is introduced into the cavities which then blocks the xylem and phloem. She also introduces pathogenic fungi such as Fusarium spp. The combination of this damage usually kills the tree.

Warm spells in early February may stimulate the females to emerge and starting looking for a home. Females bore into the twigs, branches or small trunks of susceptible hosts. The growing brood feed on the fungus rather than the wood.

It takes about 55 days for the insects to complete one generation. New females mate with their brothers before emerging to attack more trees.

So, what do you do? Keeping your trees in good health is very important. Healthy trees can withstand a low level of beetle infestation. Trees that are drought stressed, injured or excessively pruned strongly attract the beetles. Providing adequate fertilization and timely irrigation will help.

Pyrethroid insecticides such as bifenthrin and permethrin can be used as preventive sprays to repel invading female beetles but you have to know when they’re coming.

You can construct a trap out of a wood bolt, about two feet long and two to four inches in diameter. Any hardwood will work. Drill a ½ inch diameter hole in the center of the bolt about 12 inches deep. Fill with 190 proof grain alcohol and place the traps at waist high along a woodland border.

When toothpicks are observed, it’s time to spray. The traps should be placed at the beginning of February.

What’s going on in 


Feb. 19: Beekeepers Meeting 7 p.m. at the Ag Center

Feb 20: TCCA Meeting 7 p.m. Dinner costs $6. Call for reservations (706) 443-7697 Topic: 4-H and FFA Activities. Program starts at 7:30 p.m.

4-H Camp sign up: Junior Camp, Cloverleaf Camp, Wilderness Camp and Marine Resources camp. Call the office: (706) 883-1675

Feb. 22:  Hay and Baleage Short Course, Carroll County Extension, call (770) 836-8546 to register.

Feb.23: Maintain and repair small engine equipment, UGA Griffin Campus, 8:30 a.m. to 2 p.m. To register online with a debit or credit card, go to, or preregister by contacting Beth Horne at (770) 228-7214 or

March 2: MGEV Advanced Training Landscape Safety, Call Spalding County Extension, (770) 467-4225 to register.

If you have any questions or concerns, stop by or call the office. UGA has a wealth of information for home and property owners.