Wood is the principle construction material in use in Hawaii, and termites are the most economically destructive insect pests in the State. Improved methods for protecting wood products and wood in service are needed by the general public, and by the construction, forestry, and forest products sectors. The purpose of this study is to determine the distribution of termites in Hawaii, identify and evaluate termite-resistant wood products for use or manufacture in Hawaii, and determine which soil insecticides are most effective for termite prevention under tropical environmental conditions.

OBJECTIVES

1) To define and monitor the distribution of termite species, and routes of introduction, in the Hawaiian Islands.

2) To develop and evaluate improved wood products incorporating effective wood preservatives and naturally durable timbers.

3) To determine the efficacy under tropical conditions of soil insecticides applied for termite control.

APPROACH

A field survey will be conducted for termite occurrence on the various Hawaiian islands. Novel wood preservatives, naturally durable timbers, and engineered wood products will be evaluated for termite resistance in laboratory tests; and in subsequent field tests at sites occupied by the Formosan subterranean termite. The behavioral and physiological modes of action of borate wood preservatives will be assessed by a combination of laboratory and field foraging arena assays, and biochemical assays. The longevity of soil insecticides applied for termite control will be determined by bioassay of samples taken annually from six field sites on the islands of Oahu, Kauai, Maui, and Hawaii.

(1) A collaborative project was initiated with USDA Forest Service researchers to describe the effects of disturbance on subterranean termite foraging in Hawaii and the continental USA. We determined that both the presence of dead termites and stress due to capture and return to foraging sites decreases termite feeding. In a laboratory foraging arena, it was observed that water (such as a heavy rain) stimulated increased foraging activity. Studies are in progress to examine the influence of caste proportions on termite sensitivity to disturbance. (2) Field studies in Hawaii and Japan with borate and other wood treatments demonstrated at least 9 (Hawaii) to 10 (Japan) years of efficacy of borate treatments against the Formosan subterranean termite. Laboratory feeding studies revealed that boron ingestion rates differ depending upon the chemical nature of the boron compound used in wood treatment. (3) The soil termiticide fipronil continued to perform well 10 years after application, although a small decline in activity was noted under the extreme rainfall conditions found in Hilo, Hawaii. (4) A curriculum and public education project was conducted in 85 public school classrooms in Hawaii, increasing the termite prevention knowledge and awareness of residents on Oahu, Maui, and Island of Hawaii.

Each year of efficacy of the methods identified in this project equates to an annual savings of over $27 million in termite control costs for Hawaii residents. Our emphasis on low-toxicity termite management methods, such as borate wood treatments, termite baits, and soil insecticides with long residual but low mammalian toxicity, will result not only in greater protection of buildings in the American Pacific, but also a safer and healthier urban environment. Surveys of termite distribution in Hawaii and studies of termite foraging behavior are necessary to improve bait application methods for subterranean termites. Our results are adopted quickly by local industry, the public, and the Department of Defense in the Pacific.

PUBLICATIONS (not previously reported): 2005/11 TO 2006/09

1. Higashiguchi, D.T., C. Husseneder, J.K. Grace, and J.M. Berestecky. 2006. Pilibacter termitis gen. nov. sp. nov., a novel lactic acid bacterium from the hindgut of the Formosan subterranean termite (Coptotermes formosanus). International Journal of Systematic and Evolutionary Microbiology 56: 15-20.

2. E. L. Vargo, C. Husseneder, D. Woodson, M. G. Waldvogel and J. K. Grace. 2006. Genetic analysis of colony and population structure of three introduced populations of the Formosan subterranean termite (Isoptera: Rhinotermitidae) in the continental United States. Environmental Entomology 35: 151-166.

3. Grace, J.K., A. Byrne, P.I. Morris, and K.Tsunoda. 2006. Performance of borate-treated lumber after 8 years in an above-ground termite field test in Hawaii. International Research Group on Wood Preservation. Stockholm, Sweden. IRG Document No. IRG/WP 06-30390. 8 pp.

4. Tsunoda, K., A. Byrne, P.I. Morris, and J.K. Grace. 2006. Performance of borate-treated lumber after 10 years in a protected, above-ground field test in Japan (final report). International Research Group on Wood Preservation. Stockholm, Sweden. IRG Document No. IRG/WP 06-30395. 8 pp.

5. Woodrow, R.J., J.K. Grace, and R.J. Oshiro. 2006. Comparison of localized injections of spinosad and selected insecticides for the control of Cryptotermes brevis (Isoptera: Kalotermitidae) in naturally infested structural mesocosms. J. Economic Entomology 99: 1354-1362.