Extension Master GardenerSM Volunteers of Buncombe County

Insect Pests

Got ants in your pantry? Tiny ants can be a big bother!

Ants-Ants-Ants_byFarisAlgosaibi_FlickrThat’s the header for a Texas A&M Bulletin that came up when I went searching for an answer to the question “Is the home invasion by ants this season related to our drought?” The answer is “yes”—in North Carolina, too. And because a single colony can be thousands of ants, you may see ants trailing into your kitchen, bathroom, or anywhere in your home they find water or food. 

Ants that come inside
When outdoor temperatures get hotter and conditions get drier, humans aren’t the only ones coming indoors for water and food. Ants, particularly tiny (1/8-inch) odorous house ants, are marching inside, too. Odorous house ants, Argentine ants, and acrobat ants are all attracted to sweet substances indoors. Little black ants and pavement ants are also home invaders, and they are attracted to both greasy and sweet foods. 

Ants as outdoor pests
All these ant species feed on the sweet honeydew produced by aphids, scale, and whiteflies. Ants can become a serious problem outdoors, too, by protecting these pests from natural enemy predation.

What to do?
Perhaps when “more normal” weather returns these ants will go back outdoors, but don’t count on it. Practice careful sanitation indoors: quickly wipe up any ants that you find and clean the surface they’re on with soapy water. Try to eliminate attractive food sources by storing foods in ant-proof containers. Treatment with household insecticides may be helpful, but baits must be attractive to the particular ant species invading your home. 

Prevention
Caulk or block any access points to the inside of the building, such as around doors, windows, electrical wires/outlets, water pipes, and foundation cracks. Look around outside to eliminate nesting areas and food sources near your home. Keep mulch, plants, and piles of any kind—firewood, stones, and so on—away from your foundation. Trim shrubs and trees that bear fruits, berries, or are susceptible to honeydew-producing pests so they are not touching your house.

And pray for rain!

Article written by Glenn Palmer, Extension Master Gardener Volunteer. 

Photograph: “Ants Ants Ants” by Faris Algosaibi, https://www.flickr.com/photos/siraf72/with/11500322673 

To learn more, visit https://www.ces.ncsu.edu/depts/ent/notes/Urban/ants.htm

Attention Gardeners and Campers! Emerald Ash Borer a Threat to NC Trees!

The North Carolina Department of Agriculture implemented a statewide emerald ash borer (EAB) quarantine effective September 2015. The quarantine prohibits moving pieces of hardwood shorter than four feet out of state into non-quarantined areas. The restriction only applies to hardwoods—deciduous trees—because the EAB does not attack conifers—needle-bearing evergreens. The “less than four feet” restriction eliminates lumber, which is unlikely to carry live EAB eggs or larvae after the milled wood is kiln dried. But it does apply to firewood, removed trees, and tree debris.

Image of emerald ash borer adult by David Cappaert, Michigan State University, Bugwood.org.
Image of emerald ash borer adult by David Cappaert, Michigan State University, Bugwood.org.

How the EAB quarantine affects gardeners and campers
The emerald ash borer is an Asian wood-boring beetle that accidentally arrived in North America, first showing up in Michigan and Ontario in 2002. It’s been gradually expanding its territory and by 2013 arrived in North Carolina. Although the beetles can fly from tree to tree, the movement of firewood is the leading accomplice in moving the EAB larvae from place to place. To reduce the risk of infesting our trees, the message to us on the EAB is “Don’t move firewood around. Burn it where it grew.”

Fringe trees are at greatest risk
Four ash species are native to North Carolina, but most are found in the eastern part of the state. Green (Fraxinus pennsylvanica), white (Fraxinus Americana), Carolina (Fraxinus caroliniana), and pumpkin (Fraxinus profunda) ashes are occasionally found here in the mountains, but the greatest threat from the EAB is to the American fringe tree (Chionanthus virginicus), a close relative.

Tiny holes in tree bark are signs of emerald ash borer larvae.
Tiny holes in tree bark are signs of emerald ash borer larvae infestation.

Signs of EAB infestation
Unfortunately, an EAB attack is very difficult to identify. Eggs are laid on the bark and the larvae make a small, 1/8-inch, D-shaped entry hole that is hard to see on the rough bark. By the time the adults emerge, the damage is done. Dieback starts in the upper branches and death of the tree typically occurs after two or three years.

What you can do
Although there is systemic insecticide available, our best hope is to slow the advance of the EAB to allow development of an effective protective measure. Gardeners should watch fringe trees and ashes for signs of infestation. Avoid planting these trees in your landscape until more is understood about the EAB threat.

Campers and picnickers, don’t bring firewood home!
Burn that wood where it grew.

Article written by Glenn Palmer, Extension Master Gardener Volunteer.

For help identifying ash and fringe trees, visit these websites:
https://www.cals.ncsu.edu/plantbiology/ncsc/tnc/fraxinus.htm
https://plants.ces.ncsu.edu/plants/all/chionanthus-virginicus

Act Now to Protect Rhododendrons from Stem Borers

Look for signs of stem borers on rhododendrons, azaleas, mountain laurel, and blueberries
Adult borers—slender long-horned beetles—emerge from hibernation in the soil at the base of these shrubs, climb up stems, and lay eggs under the bark. On hatching, the young larvae bore into the stem and then turn downward, headed for the soil where they’ll spend the winter. Everything above the entry point on the stem will gradually wilt away.

In addition to rhododendrons, the stem borer, Oberea myops Haldeman, also attacks azaleas, mountain laurel, and blueberries. It is alternately called the rhododendron stem borer, azalea stem borer, or blueberry stem borer, depending on host plant affected.

Rhododendron stem cut away to chow tunnel of stem borer, Oberea myops Haldeman.
Rhododendron stem cut away to show tunnel of stem borer, Oberea myops Haldeman.

Symptoms
Symptoms to look for include a small hole in a stem and frass—fine sawdust-like pellets—on stems, leaves, or underneath the shrub. Look above where you see the frass and you’ll find the hole where the borer pushed these deposits out of the stem. Or, worst case, you’ll see a stem with drooping leaves. These are all signals that the borer is somewhere inside the stem below that hole. 

Solutions
From the hole, feel your way down the stem to the next joint, and with sharp pruners, cut off the section of the branch above that point. Make good, clean pruning cuts because in addition to searching for the insect, you are shaping the shrub.

Look at the cut stem. If there’s no hole in the center of the stem, you’ll know that the borer is still inside the stem above your cut. However, if there is a hole in the stem, the borer is deeper than your cut and you’ll need to repeat your pruning lower down. Dispose of the cut-off stem portions in a plant disposal or burn pile. 

Control and prevention
If you’ve had a history of borer problems on rhododendrons, azaleas, and mountain laurels, check your garden center for an insecticide labeled for borer control with a pyrethroid insecticide, such as permethrin or cyfluthrin. Apply after the new growth has hardened off about mid-May; apply again in early June. Be sure to read and follow the insecticide label for specific application instructions. For blueberries, pruning your plants every year in late winter is usually sufficient to control stem borers.

For more information, view the North Carolina State University Azalea Pest Management Calendar at http://www.ces.ncsu.edu/depts/ent/notes/O&T/calendars/note052.html and Pruning Blueberries at https://growingsmallfarms.ces.ncsu.edu/wp-content/uploads/2016/02/Pruning-Blueberrries-25JAN14.pdf?fwd=no. 

Article written by Glenn Palmer, Extension Master Gardener Volunteer.

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Buncombe County Extension Office
49 Mount Carmel Road
Asheville, NC 28806
Helpline 828-255-5522

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