WICHE: How to deal with carpenter bees and ants

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Insects are useful in some ways but could be harmful to your decks and fences.

By Jeneen Wiche

The carpenter bees are doing a number on our house! We perfectly fit the profile of a desirable place to lay your eggs for this rather docile bee, and they are busy around the frame of the garage as I write. I do have a plan.

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 and they sort of become acquaintances, because they are always there hovering about.

I suppose this is way I never took action against them for so many years. The time has come, however, to stop the tunnel because of the pending damage being done to the frame of the garage (part of the problem here is that downy woodpeckers gouged out some holes trying to get to the larvae inside last year.)

Carpenter bees look like bumble bees, but bumbles nest in the ground, and carpenter bees nest, you guessed it, 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.

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 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 around 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 they are most active outdoors 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 you will have to appreciate the fact that ants aerate the soil and can help to control grubs.

If you can’t reconcile their presence, than you can opt to treat the active infestation with an insecticide labeled for ants.


Read more of Jeneen Wiche’s columns at www.SentinelNews.com/agriculture.