Are You Bugged?

Two types of wood borers that usually attack softwood house logs are commonly known as Flat-headed or Round-headed Wood Borers. The adult of the round-headed borer (larva) are commonly called Pine Sawyers or Long-Horned Beetles.

These borers lay eggs in small pits in the bark and the eggs hatch in 2 to 4 weeks. Larva feed for a few weeks just under the bark, boring into the log. These borers feed deeper into the wood as it dries.

The life cycle is usually 1 to 2 years, but larvae may feed for at least 6 years when wood moisture is low.  Powderpost beetles are small wood-boring beetles that measure 1/8" to 5/16" long. These beetles attack sapwood of ring-porous and diffuse-porous hardwoods that have a high content of starch. These beetles also reinfest milled lumber. Tell-tale signs of this pest are small piles of fine brown flour-like wood material.

Powderpost beetles seem to prefer unheated areas; thus their infestation seems to be more of a problem in seasonal homes. As a preventative measure, the use of borates (see PeneTreat ) and coating wood with a finish helps to make infestation more difficult. As a spot treatment insecticides such as Bug Juice (just mix with a little stain) can be injected into holes with a glue syringe.

Carpenter Ants can sometimes be a problem if wood remains moist and wood rot occurs. If they are a problem, treat with PeneTreat or an approved insecticide. Also look for the cause of the moisture and try to eliminate it. Carpenter ants can enter a building by way of vegetation that may touch the building. To help prevent this, trim bushes and trees touching the building and watch for rotting stumps that could have rotting root systems underground near your building.

Insects do not have to be a problem in your log home. Design your building to keep moisture away from it so that moist wood does not encourage insect problems. Stain additives such as Bug Juice or NBS 30 and wood treatments also help to deter problems. Also, the use of Manus-Bond caulking will aid in deterring insects.

You see it every year around mid to late August, flies gather around screen doors and inside windows searching for warmth. The most common of these flies is the Cluster Fly. They tend to be larger than the common housefly and are dark gray in color. They hibernate in the house structure through the colder temperatures but will emerge from hibernation through warm spells, filling windows with their sunlight dances.

The good news about Cluster Flies is that they are harmless to humans and will not destroy property. Also, they do not breed while indoors, despite their numbers. The cheapest means for control is the good, old fly swatter. Pest strips also work well. For large swarms, a vacuum cleaner can be used for removal from screens and windows. Insecticides may also be used to control these flies, but ask yourself if it is really worth dealing with a poison to control an extremely harmless pest. If you do decide to use insecticides, be sure to follow the instructions and cautions on the label.

To help minimize the number of flies that can enter into your home or cabin through the fall, make sure that the screens around windows and doors are tight fitting and free of holes or tears. A finer mesh screen may be needed to prevent them from entering. Also, since flies are attracted to the warmth of a house, minimizing the amount of time that doors are left open will help out considerably.

We have had a number of information requests for dealing with these problematic wood borers. The Xylocopa or large carpenter bees are the ones that do the most damage, boring approximately 1/2" diameter tunnels into logs and other wood surfaces including decks, overhangs, fence rails, etc. The tunnels become a threat for infestation of wood-decaying fungi or other insects, such as carpenter ants.

 

Treatments Insecticidal sprays and dusts such as those included in the Bug Kit above are available. These types of products may need to be applied every couple of weeks for awhile to ensure effectiveness. Apply them at night while the hive is asleep for maximum impact. Beware that some insecticides have been banned but not yet removed from store shelves. Consider the potential health risks of using such poisons in your home (young children are the most susceptible). If you have an exterminator do the job professionally, find out what they are using and if those chemicals have been banned in your area. Carpenter bees are known to dislike painted and varnished wood while stained wood is said not to deter them. If you are having or have had problems with Carpenter bees, consider adding Bug Juice or NBS 30 to your finish when you recoat your house again. If chemicals aren't your bag, you can give the kids a project with a couple of fly swatters. The males don't sting and the females are known to be more reluctant to stinging, unlike other bees, wasps, and hornets.

 

However you choose to rid your logs of carpenter bees, consider spraying PeneTreat in the tunnels afterwards to help guard against wood-decaying fungi. Just mix up some PeneTreat in a spray bottle, pump sprayer, or squeeze bottle and administer it into the holes. Also, be sure to seal off the tunnel entrances by pounding in wooden dowels or by using Caulking, wood putty, or by mixing WoodEpox and sawdust.

Pest Control Starts with Recognizing the Culprits

by Paul Storch, Minnesota Historical Society Objects Conservator.

Reprinted from The Minnesota History Interpreter, Vol. 24, No.7, July 1996, with permission of the Minnesota Historical Society.

We suspect that our historic house is infested with bugs. What are the signs of infestation? And what should we do about it? There are several species of insects that feed and nest in the organic materials commonly found in buildings, furnishings and clothing. In this article we will describe the main insect pests that infest wooden buildings. A future TechTalk will deal with pests that attack furnishings, carpets and clothing.

 

This will not be a how-to treatise on controlling pests. Due to the toxic nature of chemicals used, pest control is best left to professional exterminators. Rather, this article will tell you how to identify an infestation and what to look for in a pest control contractor.

 

Common Culprits In the Upper Midwest, where many homes are built with hard-woods such as oak, maple, hickory and ash, the insects most likely to cause damage are powderpost beetles, carpenter ants and termites.

 

Powderpost beetles make small holes in unfinished wood such as joists, framing timbers and the underside of floor boards. They can damage painted surfaces, too, but will more commonly be found on the underside of painted buildings. The telltale sign of an active infestation is a fine, light-colored sawdust near the hole. Look for holes and small piles of sawdust on the ground under floor joists and outer beams.

 

Both adult beetles and feeding larvae bore tunnels into the wood and weaken it internally. Larvae are active when the wood is moist but become dormant during the winter season when the relative humidity drops.

 

Carpenter ants are common in Minnesota because they carry a chemical in their bodies that acts as a natural antifreeze and so enables them to withstand cold temperatures.

 

Houses most subject to attack by carpenter ants are frame buildings without basements or those with partial basements, low foundations or open, rambling porches, and buildings of loose construction such as rustic cabins.

 

Ants prefer moist, rotting timber around foundations but will also infest dry wood. Structural members most likely to become infested are porch pillars and supporting timbers, sills, girders, joists, studs and casings.

 

One warning sign of an infestation is a swarm of winged ants emerging from the walls in early spring. Another clue: a faint rustling sound in walls, floors and woodwork. Look for droppings and debris near slit-like openings in wood surfaces under porches and in basements and dark closets.

 

Termites may occur in southern Minnesota. They nest in the soil and burrow up into wooden structural members of buildings. Termites feed on fungus so conditions that support fungus growth will be conducive to termite infestations.

 

These insects are sometimes difficult to detect by nonprofessionals until the infestation causes severe structural damage. If you own a historic structure that has never been checked for termites, call a local pest control operator (PCO) for advice on whether or not you need an inspection.

 

Tips for Prevention Because all three types of insects prefer moist environments, the best way to prevent infestation is to control humidity in and under your building.

 

Beetles and ants also like wood that is high in starch content, so be cautious when introducing new lumber to your historic structure. If you are planning any new construction in or around your building, inspect the lumber for infestation at the point of purchase.

 

Carpenter ants can enter a building from trees and bushes that touch it. Keep nearby growth trimmed. Also remove any rotted stumps or firewood within 50 feet of the building. Eliminating wood! soil contact also is desirable but may not be practical with a historic building.

 

What to Do If You Spot Trouble There are several ways to detect insects, from sticky traps and visual checks to electronic sensors and termite-sniffing dogs. Combine the first two methods for the most economical and efficient means of detection.

 

Sticky traps and pheromone (sexual attractant) traps are commercially available to aid in monitoring for insect activity.

 

Also conduct a thorough inspection of your building, both inside and out. Make notes about the affected areas and take photographs, if possible.

 

Try to collect specimens (live or dead) of the insects. Keeping them as intact as possible place them in a small, tightly closed container such as a plastic pill bottle or film canister. Because different genuses and species of insects may require different means of control, it is important to have whole specimens.

 

All of these measures will serve as a record of your infestation and will help you describe the problem to a conservator or licensed PCO.

 

How to Choose a Pest Control Operator When contracting with a PCO, make sure they are licensed with the state. Find out if they have worked on historic structures before. Ask if they are familiar with the procedures of Integrated Pest Management (IPM).

IPM is a state-of-the-art approach to pest control that emphasizes structural and behavioral methods of eliminating pests before resorting to chemical means. Even if chemicals prove to be the best solution for your problem, you will want to adopt an IPM program for your building after treatment to guard against reinfestation.

 

Treatment Methods Consult your PCO or a conservator for information on available treatment methods arid their appropriateness for your particular problem.

 

The least toxic means of pest control is temperature modification (heating or freezing) this is not practical for whole structures.

 

Chemical treatment of infestation usually involves spraying an insecticide around the perimeter of the building and in interior spaces such as basements and attics.

 

Be certain that your PCO follows the application instructions carefully. To protect textiles, leather items and other sensitive materials from accidental spraying, move all furniture and objects away from the walls and cover them with polyethylene.

 

Sometimes more drastic treatment - whole-building fumigation- is necessary. This involves tenting the entire structure in polyethylene sheeting and introducing gaseous fumigants such as methyl bromide or sulfuryl fluoride into the tented space.

Both of these chemicals are being phased out for environmental reasons and replaced with less toxic fumigants such as carbon dioxide/phosphine, which may or may not be available yet in your area.

Most fumigants, including less toxic ones, can adversely affect materials such as leather and rubber. Consult an objects conservator before proceeding.

Some final words of advice for dealing with this and other threats to the well-being of your historic building: Don't panic. Investigate thoroughly. And proceed with caution.