NATIVE WOOD BORER.

New Zealand Herald, Volume LIX, Issue 18131, 1 July 1922, Page 11

NATIVE WOOD BORER.

DESTRUCTION OF TIMBER.

ENTOMOLOGIST'S REPORT.

Tim borer grub, which was recently described as a new and destructive type, was submitted by Mr. A. Cummings, a builder, of Otahuhu, to Mr. David Miller, Government entomologist, for examination. The grub was first noticed in some timber stacked at Buckland's Beach. Mr. Miller reports that the grabs are in a very young state, and only recently The shape of the holes combined with a microscopic examination of the grubs themselves, tends to show that the insect is one which is already causing very extreme damage to buildings infested by it, so much that the infested parts collapse. This insect is a native beetle of the " hn-hn" type, bnt smaller, and known as Ambeodontus tristis. In the case under discussion, the female beetle has recently laid a batch of eggs, and the grubs hatching from these have entered the wood at one spot, as shown in the specimen. As they grow they spread iu all directions throughout the wood, cutti'jg larger and larger borrows, and if the length of the wood permits, will travel through it for many feet. The result is that the infested wood becomes honeycombed and greatly weakened. The grub when full grown measures about fin. long, and transforms to the pupa within the wood ; from this the adult beetle, a narrow bodied insect, about the size of the grub, emerges by cutting through the surface o£ the wood, a rather oval hole just under three-tenths of an inch across its long axis. Consequent'y. although the entrance of the grubs is confined to a patch of several small holes the exits of the adult insects are scattered over the whole surface of the wood and are quite conspicuous. This insect, adds Mr. Miller, is included in his forthcoming work, " Introduction to Forest Entomology in New Zealand," and is one of the species upon which he is working with a view of gathering information on it* life history in order that control methods might be adopted.