Powder post beetle

An insect of the family Lyctidae in the order Coleoptera of the class Insecta. Although it is tropical, it is widely distributed throughout the world and can be found throughout Japan except northern Hokkaido. The adult body length is 2.2-8 mm, and it is brown, elongated and flat. It is well known as a major pest of lauan and oak wood, but it also damages various hardwoods and dried bamboo. The adult makes small holes in the damaged wood from May to July, excretes white powder and exits. It lays eggs in the xylem that appears on the surface of the wood. The larvae feed on the inside of the wood without emerging to the outside, and in autumn they build a pupal chamber near the surface and pupate the following spring. It does not damage the heartwood of hardwoods or conifers at all. Damage is discovered when the adults emerge after the larval stage has finished feeding, so prevention is the first step in preventing damage by this insect. Painting the surface of wood can prevent eggs from being laid, but in recent years, treated lumber and plywood have become commercially available. For lightly damaged wood, the best way to eradicate them is to apply or spray insecticide or inject it into the escape holes.

There are about 90 species of this family in the world, and in Japan there are four other species in addition to this one, all of which are distributed in limited areas and cause damage to dried hardwood such as lauan wood. The Araage flat-head beetle also parasitizes bamboo.

[Teru Nobuchi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

昆虫綱甲虫目ヒラタキクイムシ科Lyctidaeの昆虫。熱帯性であるが広く世界に分布し、北海道北部を除く日本全土に産する。成虫の体長2.2～8ミリ、茶褐色で細長く扁平(へんぺい)。ラワン材、ナラ材の大害虫として有名であるが、各種の広葉樹やタケの乾材も加害する。成虫は5～7月に被害材に小孔(こあな)をあけ、白粉を排出して外に出る。産卵は材表面に現れた導管内に行う。幼虫は外部に現れることなく材内部を食害し、秋に表面近くに蛹室(ようしつ)をつくり、翌春に蛹(さなぎ)になる。広葉樹の心材や針葉樹はまったく加害されない。被害の発見は幼虫期の食害の終わった成虫脱出期であるので、この虫の被害を防ぐには予防が第一である。材表面を塗装すると産卵防止効果があるが、近年は防虫処理された製材や合板が市販されている。軽微な被害材での駆除は、殺虫剤の塗付や散布、脱出孔への注入などがよい。

　この科の昆虫は世界に約90種いて、日本には本種のほかに4種が分布し、いずれも地域的に分布が限られ、ラワン材などの広葉樹の乾燥材に被害を与えている。アラゲヒラタキクイムシは竹材にも寄生する。

［野淵　輝］

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