Dealing with insect carpenters — bees and ants

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By Jeneen Wiche

I absolutely do not approve of killing bees. In fact, we are in a bit of a crisis with a diminishing population with the suspected cause being the use of pesticides, notably neonicotinoids. I do not fear bees, I am not allergic, and I can happily co-exist — except that they are eating my house. Or, rather they are tunneling into the wood that makes up my house so they can lay eggs and have lots of babies.
I am talking about the friendly carpenter bee that we are actually killing only because if we don’t we will have a serious structural problem. I long ignored them and now we are paying for it. We are not using chemicals, but rather strategic whacking with the hand and a stomp once the bee is flung to the ground. We have no other choice. Approximately 20 bees have been removed from the scene of the crime in the last three weeks. It’s been stressful on all involved.
Carpenter bees are essentially harmless. The male, who hovers about, has no stinger. The female tunnels and lays her eggs; when she does come out you would have to handle her for her to sting. I’ve never been stung by one (even hand-whacking them to the ground). They sort of become acquaintances because they are always there hovering about. I suppose this is why I never took action against them for so many years. Two years ago, the straw that broke the camel’s back was when the downy woodpeckers showed up and gouged out some holes as they worked to get the bee larvae inside.
Carpenter bees look like bumble bees, but bumbles nest in the ground and carpenter bees nest in tunnels that they excavate in bare, soft wood (our house is unpainted western cedar). They are less likely to tunnel into painted or pressure treated wood.
As I said, I used to ignore them, but they can cause structural damage if they continue to tunnel, year after year, in the same wood. The adult bee from this spring’s eggs will emerge in late summer. These bees will over winter in the tunnels and emerge next spring and make new tunnels or widen existing tunnels to lay their eggs. This is where the problem lies. If you feel that too much activity is taking place in structures like decks, then treat the new tunnels with a residual insecticide like Sevin inside the entrance hole. Wait a week and then plug the hole with a dowel rod or wood putty.
Bees are good, however, so if there is no apparent structural damage just embrace your garden dwellers. For example, I have some decoy places for them to lay eggs. I leave an old tobacco stake in the corner of the patio and they use this instead of the house.
There seems to be an equally large amount of carpenter ants scurrying around in the garden, too; none in the house so far. Carpenter ants are large, brown to black ants that hollow out soft wood for their egg nests. Decks, fences, old stumps or the baseboards inside your home are common places to find daytime activity. You will see sawdust that is sandy in appearance in the areas where they are most active, which, outdoors, is usually in the garden. Generally they only find their way inside your home in search of food, then they return to their outside nest. Their colonies are not always found in wood. Any hollowed, dark, cool place is appealing. They do, however, prefer soft, moist wood for their egg nests.
Boric acid is a good treatment for indoors because it is non-toxic to pets. Professionals should be called in for dramatic in-home infestations. For outdoors, the problem can be remedied by removing desirable habitat like rotting stumps or wood. Or appreciate the fact that ants aerate the soil and can help to control grubs. If you cannot reconcile their presence, then you can opt to treat the active infestation with an insecticide labeled for ants.