Field exposure of Pinus heartwoods to subterranean termite damage (Isoptera: Rhinotermitidae, Mastotermitidae)

摘要

Four field tiials were conducted to evaluate responses of the Australian subterranean termites Coptoteimes acinaciformis (Froggatt) and Mastotermes, darwiniemis Fioggatt to untreated softwood timbers The aim of the research was to determine whether the termite resistance of the heartwood of maritime pine (Pinuspinatfer Aiton) and of the F_1 hybrid of slash pine (P. elliottii Englem var elliottii L. & D.) X Caribbean pine (P. caribaea Morelet var hondmenus Barrett & Golfair) was equivalent to that ofslash pine heartwood Containers with test specimens of maritime pine heartwood and sapwood, and slash pine heartwood and sapwood, and F_1 hybrid heartwood and sapwood, together with feeder specimens of radiata pine (P. radiata D. Don) sapwood, were prepared. These containers were placed on concrete brick assemblies, in above-ground, weather -protected situations in areas of high termite hazard The work with C acinacifoi'mis was conducted at Beerburrum, in south-eastern Queensland, Australia, and termiteresponses were determined by losses of mass over a period of 17 weeks, The work with M. darwimemis was conducted at Tbwnsville, northern Queensland, and termite responses were determined by losses of mass over a period of 47 weeks. The ranking in susceptibility of the timbers is as follows: maritime pine sapwood > slash pine sapwood > F_1 hybrid sapwood > slash pine heartwood = maritime pine heartwood = F_1 hybrid heartwood. The heartwood of maritime pine and of the Fj hybiid of slash X Car ibbean pines is highly resistant to damage by the subterranean termites C. acinaciformh and M. darwiniemh, when used in Hazard Class 2 (H2) (that is, internally above-ground) situations. Accordingly, with respect to C acinaciformh and M. darwiniensh, we recommend that limitations on the use of heartwood unpenetrated by preservative in H2 situations be removed ftom Australian Standards and State regulations for maritime pine and the hybrids of slash X Caribbean pines.