Featured Creature: Horntails and Wood Wasps

The names “wood wasp” and “horntail” describe several kinds of wood-boring insects in the Order Hymenoptera, Family Siricidae. Of greatest concern are the large, non-stinging wasps that are attracted to and complete their life cycles in newly dead or dying conifer trees. If timber is salvaged from these trees, adult wasps may emerge from infested lumber in recently completed structures (see Figure 1). 

Figure 1. Wood sawn from a tree damaged by Sirex noctilio (Photo by Dennis Haugen, Bugwood.org).

There are several species of horntails, all looking very similar. They are large wasps, generally 1 inch or longer. They have a wasplike appearance but lack a noticeable constriction in the abdomen, as seen with many wasps. They are often black or metallic dark blue or combinations of black, red, and yellow.

 The male and female have a similar body shape, except the female is larger and has a very prominent ovipositor. The female can use her ovipositor only for egg laying; she can’t use it to sting in defense.

The female drills her ovipositor nearly 3/4” into the wood of a weakened or dying tree and lays 1 to 7 eggs.

She may lay up to 200 eggs in her lifetime. Eggs hatch in 3 to 4 weeks, and larvae tunnel into the wood parallel with the grain. Larval feeding continues through 5 or more immature stages, which take at least a year and as many as 5 years in cooler climates to complete. The tunnel, or gallery, usually measures 10 to 12 inches long at completion.

Pupation takes place at the end of the gallery. After 5 or 6 weeks as a pupa, the adult emerges by chewing through about 3/4” of wood, leaving a round exit hole 1/4” – 1/2” diameter.

Although they can be extremely annoying, and can look intimidating to many people, horntails are not harmful to humans or structures. They only attack trees and won’t bore into wood in buildings or furniture, and therefore, will not re-infest structures. Fortunately, the damage is more cosmetic and does not cause any real structural damage. The only real management strategy would be to repair or replace any cosmetic damage. 


Spring Cleaning to Prevent Pests

Most folks love spring! But with spring comes many pests – insects and others – that begin to emerge and become active in and around our homes. Fortunately, with spring also comes spring cleaning for many people. And with just a little extra time and energy, many pests can be kept at bay.

Ants, cockroaches, stored product pests, mice, and termites are just a few critters that may try to take up residence in and around our homes. Follow these cleaning and organizing tips for areas in and around the home to help maintain a pest-free environment.

Figure 1. Crumbs and other debris beneath appliances should be cleaned up (Patty Alder, NCSU).

Inside Cleaning As most of us know, the kitchen holds many items attractive to pests. Food, water, sources of heat, and harborage areas can be big draws for pests. Inevitably, food, crumbs, grease, and other debris collect under appliances over time (see Figure 1). Move the stove and refrigerator out from the wall and clean the floor beneath these items thoroughly. Go through the pantry and other places food is stored and get rid of old, expired items. Store any pest-susceptible items in sealable, pest-proof containers. Many susceptible items can be stored in the refrigerator as well. Remove items from cabinets and give the shelves a good wipe down before returning items. Lastly, don’t forget to finish by thoroughly cleaning countertops and giving the floor a good vacuuming and mopping. 

Ideally, the kitchen trash can should have a tight-fitting lid. In addition, you may consider placing your recyclables in a container with a lid – even rinsed recyclables can contain enough residue to attract pests. 

For both kitchens and bathrooms, check to make sure there are no leaky pipes or faucets. In addition, seal up any gaps around pipes with caulk or expandable foam. 

Figure 2. Cluttered storage areas, such as the garage should be cleaned and organized (Mike Waldvogel, NCSU).

Declutter closets, basements, garages, attics, or other storage areas pests may be hiding (see Figure 2). Donate or throw out unused or unnecessary items. The less stuff you having lying around, the fewer hiding places available for pests. If possible, use plastic storage tubs with tight-fitting lids to organize and store items in.

Exterior Cleaning Seal up entryways on the outside of your home. Gaps around pipes that enter the foundation can be caulked closed. 

Weatherproof doors and window frames. Make sure window and door screens fit properly and are not ripped or torn. Crawl space and attic vents should be screened to keep out unwanted pests.

Reduce or eliminate any outdoor clutter that could be serving as pest harborage. Store firewood, lumber, and other items away from the foundation. 

Trim back branches that are touching the structure. If possible, leave a 12” to 18” vegetation free zone around the foundation.

Eliminate mosquito breeding sites by clearing your yard of standing water. Anything that collects and holds water could be a potential problem. Areas/items that should be checked include:

  • Bird baths (make sure water is replaced every 2-3 days)
  • Clogged gutters
  • Drain pipes attached to downspouts
  • Buckets, watering cans, etc.
  • Saucers beneath potted plants
  • Tarps covering woodpiles or other items
  • Children’s toys, including plastic kiddy pools
  • Tires
  • Grill covers, boat covers, etc.
  • Garbage cans, recycle bins, etc.
  • Any trash or debris that can collect water

In summary, warmer weather means an increase in pest presence and activity. But with a little spring cleaning and home improvements, pests can be deterred from infesting your home and yard, making spring much more enjoyable!