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Public Radio's Environmental News Magazine (follow us on Google News)

Getting the Termites Out

Air Date: Week of

Steve Curwood talks with entymology professor Kenneth Grace from the University of Hawaii about how consumers can rid their houses of termites using high technology methods that don't require poisonous fumigation.


CURWOOD: This is Living on Earth. I'm Steve Curwood. Not too long ago, if you had termites you didn't have much of a choice. You could watch in horror as your house crumbled to the ground or you could fumigate with dangerous pesticides like methyl bromide or chlordane and wind up poisoning more than just your termites. But today there are many ecologically safer alternatives. And here to help us chew our way through them is Dr. Kenneth Grace, an entomologist at the University of Hawaii at Manoa. Hi, there.

GRACE: Hello, Steve. Glad to be with you.

CURWOOD: Dr. Grace, how do I tell if I have termites in my house?

GRACE: Well, the first thing we need to understand, Steve, is that there are 2 types of termites that might be infesting your house. There are dry wood termites, and those are termites that live above ground, directly in the wood in the house. Really, the way you know you have them is you begin to see these little piles that look like sand around the house in the windowsills.


GRACE: Those are fecal pellets. Now, you're not going to see them for oh, maybe 4 or 5, even 6 years after a colony's founded.

CURWOOD: Oh, no.

GRACE: They're rather slow-acting. Now in your area, it's going to be what we call subterranean termites, or termites that live in the soil and come above ground into your house to feed. Your house is just another stump to a subterranean termite. And because they build little soil tubes up into the structure, one can look for those tubes. If you see those little soil constructions moving up the concrete into your home, that's direct evidence of subterranean termite infestation.

CURWOOD: So in the colder parts of this country, it's likely to be subterranean termites. So what do I do if I find that I have those in my house? How can I get rid of them?

GRACE: Well, nematodes are small round worms that attack insects, are being used in some parts of the country as an alternative to chemical insecticide treatment of the soil. They will kill termites that are at the point in the soil where the nematodes are injected. But the problem is that nematodes aren't very good at hunting down the termites, and they don't live very long. We've been looking at some other pathogens or biological control methods for termites. Fungal pathogens, athlete's foot for termites, essentially, seem to offer promise because they're slow-acting, which is good. You want termites to continue to come into the area and become in contact with the pathogen. But they also seem to be rather repellent, and the termites have a lot of defense mechanisms. They will wall off areas where there is a lot of disease occurring or infected individuals.

CURWOOD: Now, what if I have a house in Hawaii, where you live, or in the warmer parts of the lower 48, as we say, and I don't want to fumigate, and I have these dry wood termites? What could I do?

GRACE: Really, the most promising alternative out there right now to an insecticide is heat treatment. We pump hot air into the building, we elevate the temperature in the wood to about 120 degrees Fahrenheit, and that will kill the termites. Now, the other methods of termite control are what we call local treatments. The major local methods of treatment are, again, heat treatment of that area, or cold, using liquid nitrogen around the wood, to bring the temperature down to a point where the termites freeze and die. Other alternatives, electro-gun, it's a high-voltage electricity that is an effective method if one can get to the wood where the termites are. And the problem is there's a lot of metal in a wall. There's nails, there's pipes, there's screws. There are things that will divert the electricity. Microwaves are also being used commercially, in California at least, for termite, dry wood termite control. Basically, you have an open microwave oven placed in front of the wood. They don't go very far; it appears to be a rather safe method from a human standpoint. But it's again very labor-intensive. One has to move this comb [word?], and it's forcing microwaves at the wood from area to another quite frequently. And there's also some potential there for charring of wall covering or the wood if the operator's not careful.

CURWOOD: You wind up with your wall looking like overdone microwave popcorn, huh?

GRACE: Well, we would hope to avoid that.

CURWOOD: Well, fortunately, Dr. Grace, I don't think I have any termites. So what do you think I should do to keep it that way?

GRACE: Well, inspection is really your key. Make sure, in inspecting your home, that there's no wood in contact with the soil. It's a highway for termites if it is, and it's very hard to control without cutting it off and physically raising the wood above-ground, putting it on concrete. Now, assuming all the wood's above-ground, what you look for is tunnels, those dirt tunnels that I mentioned coming up from the soil and up into the structure. Now actually, we're talking about less toxic methods of pest control. One could control subterranean termites by removing those tunnels, knocking down their pathways into the building wherever you see them. But that assumes that you're going to be quite religious about it and get out there and inspect regularly and remove those tunnels. Inspection, I just can't overemphasize how important that is in keeping your house termite-free.

CURWOOD: Kenneth Grace studies termites at the University of Hawaii at Manoa. Thanks for the advice.

GRACE: You're very welcome, Steve.



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