Wasps can be generally beneficial as they prey on other pests, but they can be quite a nuisance when they build their nests on your wood deck. They tend to favour such areas of homes because decks provide hidden spots for them to build their nests. Wasp stings can be quite painful and they can also can pose a danger to people who are allergic, so it is important to prevent wasps from nesting, in order to keep them away from people and pets. Horntail wasps are related to wasps but do not have the ability to sting or bite. The biggest thing to worry about with these potential pests, are the unsightly holes they can leave in the wood of your home.
Unlike most wasp species, the horntail wasps do not build their nests in the ground or attached to high terraces, but instead find decaying tree trunks or weakened timber and inject their eggs directly into the wood. As the eggs hatch, the larvae will begin to eat its way up through the wood. They usually search for timber that is already infested or decaying when laying their eggs. If the wood in which the eggs are found is then processed to create planks, palates or low grade sheets of wood, it is then possible that they emerge later in their life cycle, and you will be forced to face wood wasps inside your home.
Damage caused by wood wasps and how to prevent them
Dozens of species of wood wasps are known, and common to all is the fact that they are all attracted to wood, especially coniferous trees and they complete their life cycle in such trees, that have either died recently or are about to die. The damage they do is more aesthetic than weakening the structure of resistance and this is because their presence is not in large numbers, no more than a dozen. However, preventing even such a small number of wood wasps is important. The best way to prevent an infestation is to remove and process wood as quickly as possible. Otherwise, storing logs in a safe area is essential. If you are using firewood, you should not store it inside the house; only bring it in when you will use it.
There is, however, a certain specie which has developed in such a way that it attacks healthy trees as well. Known as the European wood wasps, it can choose not only dead timber, but live tree specimens to lay their eggs in. This increases the likelihood of the eggs remaining in wood used to make high quality lumber for commercial use.
As the female injects her eggs in the wood, she also injects a toxic mucus and symbiotic fungi that work in synergy to weaken the wood and make it softer for the larvae to eat, as the wood will be easily disintegrated. The damage that wood wasps produce is both economically and environmentally important. Thus, the wood infested by these insects loses its quality and productivity, and on the other hand, the death of massive trees in conifer forests can destroy the ecosystem in the area as well. These insects cause significant mortality rates of several species of pine trees and conifers, whether they are in your backyard, in nurseries or wild forests.
In order to prevent bringing wood wasps into your home, the best way is to carefully manage the firewood you bring inside. As the wood is brought inside the house, adult wasps may emerge from it, so it is better to not offer them this possibility.
Prevention, in the form of prompt salvage of damaged trees, or rapid utilization of cut ones would forestall most degrade introduced into lumber products by horntails. Kiln drying of processed lumber will kill developing larvae and prevent their emergence from finished products. In most cases where structural timbers in a house are infested, no control is necessary as the emergence of adults marks the end of the infestation. Damage caused to wood in use can be prevented by proper kiln-drying of fresh, green timber. Also, the use of borate wood preservatives and coating the wood with a finish will help in making it less attractive and thus prevent infestations.
When dealing with a wood wasp infestation, or even when you are just trying to prevent one, it is important to understand that wood which has no evidence does not mean it is insect free. In fact, it could just mean that the larva located in the wood are still growing and feeding and have not emerged yet. Since the exit holes are only generated when the adults leave after reaching maturity, larva in the wood feeding and growing can do so with no visible evidence to alert you they are present. For this reason, it is important to consider all areas where specific wood was utilized.
Though the adult horntails are quite noticeable and visible, they are not always the first sign which alerts the homeowner that something is active in their structure. Since woodpeckers and other types of birds can “hear” the larva working its way inside infested wood, you can see such birds start pecking away at the siding, molding, facia boards or any part of a structure which is harboring horntails larvae. They are attempting to harvest the insect and consume it for their next meal. It is easy to spot the 1/4″ exit holes left by adults as they exit and leave infested wood. You will be able to see a series of holes that will be perfectly round and can be observed in just about any type of wood. Siding, overhangs, soffits, decks, door frames, window frames, attics, basements, crawl spaces or porches are some of the more common nest sights, but any part of a structure which is wood can be a likely area for an infestation. And though these holes are used as places where the adults are emerging, it is not uncommon to find adult females using these same holes to lay eggs.
It is important to know how to deal with a wood wasps infestation, should it occur. Details on how to manage and overcome these insects can be found in our related article about “How to get rid of wood wasp infestation”. However, keep in mind that preventive measures are always necessary, as even after the infestation has been dealt with, other generations may appear and attack the same structure.