Horntails

Facts, Identification & Control

Latin Name

Family Siricidae

Appearance

What do they look like?

Horntail picture
Horntails get their name from the projection on the back of their abdomen, which often is confused for a stinger. Some people refer to these insects as wood wasps, as horntail larvae bore into wood.

  • Size: Depending on the species, adult sizes range between 12 to 40 mm.
  • Color: They are dark colored, usually brown or black. Some species have pale markings.

How Did I Get Horntails?

How Do They Get Inside?
Horntail females lay eggs in dead, dying, or fallen logs. If a property owner’s home is built using lumber infested with horntail larvae, the adult insects may emerge in homes after completion of their life cycle. Adults will chew through plaster or sheet rock walls to get to living spaces.

Improperly dried lumber from infested logs is most at risk for problems with these pests. Firewood stored inside can also contain horntails.

Signs of a Horntail Infestation

  • Exit holes in tree trunks – Adult horntails that emerge in the living space of a home can cause a disturbance. The exit holes can be unsightly, especially in wood that has been painted or stained.
  • Noise – Horntails are sometimes noisy when they fly.

How Serious Are Horntails?

Structural Damage Concerns
Horntails are actually wasps, but these insects do not bite or sting. They rarely cause structural damage since they do not lay their eggs in construction wood after it is cut and dry. But, if infested wood was used in a home without proper drying and aging, adults might show up as they emerge from the infested wood.

Horntails will not infest furniture or re-infest wood inside a home. Still, they are a nuisance to people and may cause alarm to homeowners who think their house is being destroyed by a wood damaging insect.

How Do I Get Rid of Horntails?

In most cases, it will not be necessary to do anything to control horntails. The adult horntail does not reinfest seasoned wood. It will not lay eggs in wood that is inside the home. Damaged wood can often be repaired or replaced.

Prevention
Nevertheless, homeowners can help prevent infestation by storing firewood outside the home. Firewood should only be brought in when it will be used.

If infestation is suspected, homeowners are encouraged to request an inspection by an Orkin specialist to ensure any evidence of wood damage is not from authentic wood damaging insects able to cause structural problems.

Reproduction

Eggs
Female horntails deposit their eggs into the trunks of trees. Most species choose coniferous, softwood trees, but a few species choose broadleaf, hardwood trees. Chosen trees are usually in decline from disease or attack from other insects.

Larvae
When the eggs hatch, the larvae burrow into the wood. They pack tunnels with droppings and wood shavings as they burrow. When the larvae are mature, they burrow close to the surface of the wood and make a silken cocoon inside the tunnel, where they then change into adults.

Adults
In the forest, horntails can complete the entire life cycle in a year or two. If the wood has been dried and made into lumber, the horntail life cycle can take as long as five years. When the adult comes out of the cocoon, it chews its way out of the wood. The adult makes a round hole in the surface of the wood. The exit holes are usually about 1/4″ in diameter.