Spring has sprung! Ornamental trees are blooming, flowers are growing and insects are awakening. This is an exciting time of year. Mother nature gets to show us that she is omnipotent – nothing can stop her. And one of her creatures which is active now is the wood bee. Wood bees are prevalent throughout the United States. Although there are different species, the most common is big and resembles a bumble bee. You may find it foraging around flowers, shrubs and under the eaves of buildings. This bee is unique from most because it will bore into wood to make its home. They are a nuisance and can cause damage to any wood on your property. They also bother homeowners by “attacking” them though they rarely sting. To keep your building free of wood bees, you must know their biology and habits.
WOOD BEE NESTS
Wood bees bore holes into wood overhangs, fence posts, and trees. They will crawl between cracks of siding and roofing. When they bore in wood, the hole they drill is about 1/2″ wide. This hole will go straight an inch or two and then turn 90 degrees. The following video shows close up a freshly drilled hole with a female wood bee just inside.
This new portion of the nest becomes an egg chamber. Eggs are laid at the end of these chambers and many times in “sub” chambers which stem off the main chamber. Food is placed alongside the egg and then capped and sealed tight. It is common for an egg chamber to be two or more feet long with 10 or more sub chambers. Here is what a typical wood bee hole will look like when seen on a 2×4 piece of pine.
If you could “peer” inside a hole, the typical chamber would look like this.
Typically the female wood bee will stand guard at the nest entry hole. She will defend the nest aggressively and she is armed with a stinger. Once the drilling has been completed, she will spend her days foraging for food. You may find her working Azaleas, Bradford Pears, Daffodils, Pansies and any plant which will provide pollen in early spring. Male bees will be hanging around these same plants hoping to find a receptive female who is still interested in finding a mate.
WOOD BEE BIOLOGY
The male bees are naturally curious and will buzz around anything moving including people, pets just about anything they see moving. This buzzing scares people into thinking they are being “attacked”. In fact, the male bee does not have a stinger! He has a distinctive yellow face, which may be seen while he is in flight. Female bees have no interest other than collecting food. As stated above, they have a stinger but their face is black which is in contrast to the male bees. Wood bees are commonly mistaken for bumble bees. There are two differences. 1) Wood bees are generally larger. 2) Wood bees have an abdomen which is shiny, metallic and black in color. Their abdomen has no body hair. Bumblebees have yellow and black body hair on all body parts. The following video shows a female wood bee closeup as she is chewing an entrance hole to a newly formed nest. Note her shiny metallic abdomen.
In addition to “attacking” residents, wood bees are a problem because they tend to return to the same wood or location where they were born. Old nests are used year after year. If the original nest is occupied, other female bees will drill new nests. A single nest one year will become two or three the next. Problems rapidly escalate and soon you may have hundreds of holes. When you have numerous wood bee nests, you will have numerous larva. The larva of wood bees is large and noisy. They make enough noise to attract woodpeckers. Buildings which have woodpeckers damaging exposed wood probably has some type of larval activity which is attracting the birds. This insect is most likely wood bee larva.
WOOD BEE TREATMENTS
To get rid of wood bees, you must think long term. The nuisance male bees are easy to kill with PT-515 WASP FREEZE. Try to get as close to them as possible and then spray directly at them making sure to keep the spray on them as long as it takes to kill them. This is usually 3-5 seconds. If you have a lot of females which are boring or hanging around looking for a place to bore, they can be a little tougher to kill. Use the BEE AND HORNET KILLER which seems to work a little faster with less waste.
WOOD BEE DUST
Unfortunately, killing the male bee will do nothing to stop the cycle. You must treat the nest with some material which will last a long period of time so it will effectively stop the larva. If you spray liquid residuals in their hole, you may kill the female. The eggs are protected, however, and six to twelve months later the larva will emerge. Since liquids are absorbed by porous wood, the treatment will be gone when the larva finally hatches. This means the larva have a strong chance of survival. To insure complete control, use a dust called DRIONE. It has a desiccant (dehydrating) action and when the larva emerge they will be killed quickly. It is recommended that entry holes are treated with Drione and then sealed using a special 1/2″ CORK. This will protect the dust from breaking down and enable it to last long enough to kill any emerging larva in the future. Plugging the holes with a cork instead of using wood filler means the tunnels will be accessible for emerging bees when they hatch from their protective egg chambers. When they do finally emerge (which will be either later this year or early next year), the bees will crawl over the Drione and meet their demise. The corks will also allow you to tell which holes you have treated so new ones can be quickly identified if new wood bees should appear. Since the holes can penetrate several feet, you will need to use an applicator like a HAND DUSTER. This tool will help you to apply the dust with enough force to reach deep in the nest where the eggs and larva will be living. Here is a video showing just how to treat their nests using a hand duster.
If you have a lot of holes to treat, you should consider the DUST-R. This device holds almost a whole pound of Drione and because of it’s unique pump handle design, requires very little effort to treat a hole. For large jobs, it’s a real help. Nests can be treated in a couple of seconds. If the holes are just out of reach, use the LONG REACH DUST-R which is essentially the same device except it has a series of extensions that lengthen the unit to over 7 feet long. This means the average person standing on the ground can treat nests over 12 feet high without the use of a ladder! For really high nests, the DUSTICK or the DUSTICK DELUXE KIT might be the tool for the job. This duster is over 20 feet long and can be used to access nests which are over 25 feet up with little effort! It’s also a great tool for infestations where wood bees are foraging under facia boards or siding which take forever to treat using a ladder. This video shows the Dustick being used.
To get rid of wood bees that are foraging to start new nests, you must first finish all exposed wood with a protective paint. A hard finish may deter wood bees. However, the author has had his own home attacked and the bees didn’t seem to notice the freshly painted surfaces. The Latex paint which was just applied didn’t seem to slow them down at all. Furthermore, the author has seen them bore through varnish, stain and just about any type of finish. Since cellulose is where they want to call home, wood used on any structure may become a target. If the structure is a log cabin or one with natural wood siding with shakes that are exposed, expect to be attracting wood bees every season. All wood gives off a decay odor which attracts these bees and once the structure is found the bees will start their nest making.
WOOD BEE SPRAY
To stop them from boring new nests, spray CYPERMETHRIN. This product is active against many pests including wood bees. Mix it at the rate of 1 ounce per gallon and spray it on any wood surface where wood bees may want to bore into wood trying to create a nest. One gallon can treat 500-1000 sq/ft. This application rate works well when treating cedar homes and log cabins. These structures are particularly subject to wood bees. If you want to keep them natural it means you will have to do more spraying to keep away wood bees and other wood destroying pests. Apply the Cypermethrin once every 2-4 weeks in the spring when wood bees are most active. Once a month applications throughout the summer will probably provide protection but you may need to increase the applications to every 2-4 weeks in the fall as well to get a complete season of wood bee control. Although rain and humidity will break down the chemical, it is active enough so that even trace amounts will chase these bees away and force them to find and build nests elsewhere. Most any SPRAYER will do the job and we’ve got a few that can reach up 20 feet or more making the treatment more effective. This video shows that a “pinstream” spray is best suited for reaching those overhangs and other high places where wood bees will many times want to nest.
Now that you have the chemical and sprayer, be sure to get good coverage when treating by spraying high and wide. Remember that spot applications are not suggested. In other words, if you have activity in one section of an overhang, be sure to treat all of it since the wood bees will probably just move to the untreated section. Since they can sense the Cypermethrin, they tend to avoid where it was sprayed and move to areas which are not protected. Generally, after they find it at several places on your home, they will leave altogether. Remember also that old holes release odors and smells that tend to attract new wood bees looking for a good nest sight so be sure to treat as many as possible with Drione and seal them up. This will insure they don’t become a “recycled” nest. If they are too high to access, be sure to spray them with the Cypermethrin which should offer some protection. This will make the wood bees avoid the area and help to mask the hole’s odor so it won’t be able to attract as many.
ORGANIC WOOD BEE SPRAY
For longer lasting bee repellency, be sure to add some NBS ADDITIVE to your paint/stain the next time you finish your home. Just adding it the paint you plan on using to repair and seal the nests you treat can help as well. NBS is an organic insect repellent. Formulated to be used by adding it to any paint or stain, you don’t have to do anything odd or unusual to apply it. And treatments will last 1-2 years adding long term repellency to the exterior coating. Made from plant oils, this 100% natural product isn’t a pesticide and it won’t kill any insect so you still need to dust with Drione to control existing populations. But bees don’t like the NBS (neither do wasps and other invasive insects) and they’ll avoid siding, fencing, railing, decks, logs, overhangs, soffits and pretty much any place NBS is applied. It can also be mixed with nothing but water and applied with a pump sprayer to your siding, outside furniture, trees, shrubs and any area in the yard where you’ve got some unwanted insect activity. When used in water, the residual will be a lot less compared to when it’s mixed with paint or stain so you’ll need to apply throughout the season every 1-2 months. And remember, it’s a not a pesticide so don’t expect to see anything die. For that, use the Cypermethrin.
Come spring, insects will rebound from a long and cold winter. The wood bee is just one of these insects. Treat their nests directly with Drione to insure long term control. Use Cypermethrin on decks, overhangs and fence posts to stop further nests from being drilled. Wood bee awareness and control will help eliminate these “attacking” bees from harassing you, your family and your home.
WOOD BEE PRODUCTS
Long Reach Dust R: http://www.bugspraycart.com/equipment/dusters/bg-long-reach-dust-r
Dustick Deluxe: http://www.bugspraycart.com/equipment/dusters/dustick-deluxe-kit
Insect Repellent: http://www.bugspraycart.com/exempt/additive/nbs-paint-additive-16-oz