JOURNAL OF PESTICIDE REFORM/ WINTER 2001 ¥ VOL. 21, NO. 4

● ALTERNATIVES DAMPWOOD SOLUTIONS

BY MEGAN KEMPLE wood contact is not necessary, al- though it often leads to infestation. Any condition which leads to mois- , including dampwood ture buildup in wood can encourage termites, perform an essential ecologi- dampwood termites. Wood can be- cal function: they help break down come damp as a result of leaky pipes dead wood and return nutrients and or poor gutters. Support beams may other components of this wood to the become damp due to poor ventila- soil and atmosphere.1 Unfortunately, tion. Rain-soaked firewood can also

when they perform this same function Oregon State University (Ref. 18) attract these termites. Once established, in a house or other wooden building they can extend their activities into they become a pest. In fact, they are sound wood, even relatively dry “among the most important structural A winged, reproductive dampwood termite. wood.2 Dampwood termites, unlike pests in the Northwest.”2 This other termites, have a tendency to doesn’t mean that pesticide applica- work their way upward from the foun- tions are necessary, however. If you dation to the roof rafters.8 find dampwood termites in your house, Detection there are straightforward nonchemical methods for dealing with them. Dampwood termites are hard to spot because they hide themselves to pre- Biology vent moisture loss, but you can look There are two species of dampwood for indications of termite activity.2 termites in the Pacific Northwest. The Swarms coming from the home are Pacific dampwood termite probably the most obvious sign.2 These augusticollis occurs along the Pacific University of California (Ref. 6) flights usually occur on warm evenings coast from Baja California north to Brit- in late summer or fall, especially after ish Columbia3 and also in parts of A drawing of a dampwood termite pellet. rain.3 Idaho, Montana, and western Ne- A thorough visual inspection is the vada.4,5 The Nevada dampwood ter- The Pacific dampwood termite is main monitoring technique for detect- mite Zootermopsis nevadenses6 is the largest of the common northwest ing termite infestations. Look around present in this same area, but also termite species. It has three castes: re- and under the house for damp or dam- extends to the cold, dry, high eleva- productives (the winged form), aged wood with holes or tunnels in it tions of the Sierra Nevada, Coast nymphs, and soldiers. The reproduc- and wood that sounds hollow or soft Range, and Cascade and Rocky Moun- tive caste may exceed one inch in when tapped. A screwdriver or pick is tains.4,5 In Oregon, the Pacific damp- length including the wings and is useful for prying into suspect areas wood termite is found in the western cream colored to dark brown. The sol- and opening up holes to look for ter- part of the state, and is most common diers are approximately 3/4 inch mites.9 Also look for piles of sawdust along the coast.7 (20mm) long with head and jaws com- and dead .2 Be aware of any prising about one-third of their length. condition that promotes moisture or Identification They have a large reddish brown to wood decay.9 Correct termite identification is es- blackish head and a cream-colored There are a number of other detec- sential since different termites require body. There is no worker caste in this tion methods, which vary in their avail- different control efforts.2 If you are at species; the nymphs perform this func- ability. Electronic odor detectors can all uncertain about which termite spe- tion. Nymphs are white to cream detect the gases termites emit. Al- cies is causing trouble for you, catch colored and are about 1/2 inch (13mm) though these devices are currently on a few of the termites in a jar and take long. Dampwood termite fecal pellets the market, their effectiveness has not them to your county extension agent are approximately 1/25 inch (1mm) been fully studied. A fiber-optic scope for identification. long and slightly hexagonal.2 can be used to view areas behind dry- wall and paneling. Specially trained Habitat dogs can sniff out termites and detect Megan Kemple is NCAP’s public education Dampwood termites thrive in wood termite galleries that might otherwise coordinator. with a high moisture content. Soil- be overlooked.9

NORTHWEST COALITION FOR ALTERNATIVES TO PESTICIDES/NCAP 12 P. O. BOX 1393, EUGENE, OREGON 97440 / (541)344-5044 JOURNAL OF PESTICIDE REFORM/ WINTER 2001 ¥ VOL. 21, NO. 4

Prevention and Physical commercially available. One company to kill the termites. Controls that markets the parasitic nematode As Art Antonelli, a termite expert Steinernema carpocapsae recommends Summary from Washington State University Co- them for termite control.14 To control dampwood termites, operative Extension, has written, However, NCAP found very little eliminate the moist wood in which “Avoiding situations that lead to damp- information about nematodes’ effective- these termites thrive. Repair leaky pipes ening or rot of structural wood can ness against dampwood termites. In a and roofs, make sure the area under prevent termite attack and establish- laboratory study, one species of your house is adequately ventilated, ment in most cases.”2 Steinernema (Steinernema rarum), re- and remove scrap wood that is near Remove or fix sources of water such produced well in Pacific dampwood your house. In addition, be sure that as leaking pipes and leaky irrigation termites and caused 80 percent mor- there is at least a foot between the systems.10 Get rid of shrubbery block- tality.15 This is a different species than wood portions of your house and the ing air flow through foundation vents.2 is used in the product mentioned ground. These steps will keep your If foundation walls are too low, wood above, but suggests that the nema- house in good repair while they mini- may be in contact with soil. There todes might be worth trying if your mize damage from dampwood ter- should be 12 inches of clean concrete situation is difficult to manage with mites. between soil surface and structural other techniques. wood.6 No wood near or under your References house should be in contact with soil; Heat Treatment this includes firewood, tree stumps, Heat is an effective nonchemical 1. Ebeling, W. 1978. Urban Entomology. Berkeley 6 CA: Univ. of CaliforniaÐBerkeley Div. Of Agri- lumber, and scrap wood. Downspouts control for some termites. In this pro- cultural Sciences. p. 130. should carry water away from the cess, propane heaters are used to heat 2. Washington State University Cooperative Exten- building.11 Move any soil piled up next a house or other building that has been sion. 1994. Termites: Biology, Prevention, and Control. Pullman, WA. to the house. Be sure planter boxes covered with tarps to help hold in the 3. Ref. #1, p. 146. built on the ground are at least 4 heat. After the temperature inside 4. Thorne, B.L. et al. 1993. Distribution and bioge- inches away from the house.11 Repair wood timbers reaches 130 degrees it ography of the North American termite 12 Zootermopsis (Isoptera: Termopsidae). Ann. leaky roofs. is kept at that temperature for an hour. Entomol. Soc. Am. 86: 532-544. Replacing rotten or damaged wood The entire process usually takes less 5. Thorne, B.L. and M. I. Haverty. 1989. Accurate is important. You will remove the ma- than eight hours.16 identification of Zootermopsis species (Isoptera: Termopsidae) based on a mandibular character jority of the termites along with the Several pest control companies have of nonsoldier castes. Ann. Entomol. Soc. Am. damaged wood.12 Once removed, small found that this kind of heat treatment 82:262-266. pieces of wood debris containing live can be effective against dampwood 6. Univ. of California Statewide IPM. 2001. Ter- 12,17 mites: Home & landscape. UC Pest Manage- termites can be soaked in soapy water termites but one of these compa- ment Guidelines. www.ipm.ucdavis.edu/PMG/ to kill the insects. Larger pieces can nies cautions that the technique is PESTNOTES/pn7415.html. be taken to a landfill or a natural area “probably overkill and not cost-effec- 7. Mankowski, and J.J. Morrell. 2000. Incidence of 12 wood-destroying organisms in Oregon residen- where the decomposing ability of the tive unless the infestation is massive.” tial structures. For. Prod. J. 50: 49-52. 13 termites is useful. Heat treatment will not be effective if 8. Ref. #1, p146-147. the termite nests are near or below 9. Gilkeson, L. A and R. W. Adams. 1996. Inte- Biological Control 6 grated pest management manual for structural the ground, as it will not be possible pests in British Columbia. Chap. 9. www.env. Nematodes that parasitize insects are to raise the temperature high enough gov.bc.ca/ipm/docs/chap9.html. 10. Lewis, Vernon. Undated. Cal termite page: Ques- tions & answers. Univ. of CaliforniaÐBerkeley. Dept. of Insect BIology. www.cnr.berkeley.edu/ lewis/index2.html. 11. Ref. #1, p. 167, 151. 12. Hydrix Pest Control of the North Bay, Inc. Undated. Hydrix termite control. www.hydrexheat.com. 13. Olkowski, W., S. Daar, and H. Olkowski. 1991. Common-sense pest control. Newtown, CT: Taunton Press. p. 438. 14. Hydro-Gardens, Inc. Undated. Integrated pest management: Beneficial insects. www.hydro- gardens.com. 15. Koppenhöfer, A.M. and H.K. Kaya. 1999. Eco- logical characterization of Steinernema rarum. J. Invert. Pathol. 73: 120-128. 16. Thermapure. Undated. What is Thermapure?. www.thermapure.com. 17. W.A. Stone Termite & Pest Control, Inc. Un- dated. About termite control. www.wastone.com/ If the crawl space under your house keeps wood at least a foot above the ground and is clear of about_termite_control.htm. 18. Oregon State Univ. Extension Urban Entomol- wood scraps, dampwood termite problems are unlikely. ogy. 2000. Termites. www.ent.orst.edu/urban/ Termites.html.

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