Oriental armyworm moth

This moth belongs to the family Noctuidae in the order Lepidoptera of the class Insecta. Its wingspan is about 40 mm, and its forewings are yellowish brown. It is a member of the group of moths that includes many species worldwide. Along with the closely related armyworm moth P. unipuncta , which is found in Europe and North America, it is known as a notable pest of various agricultural crops such as rice, foxtail millet, wheat, and corn. This species is distributed throughout Asia, as well as Australia and New Zealand. Recently, damage to cultivated pastures has been attracting attention. A well-known study on the migration of the adult population of this species was conducted in China, and it is said that the moths that emerge in southern China in January and February head north, breed in various places along the way, and reach northeastern China, then head south again in autumn, going through a total of five generations. This survey also included a recapture experiment using the marking method. In the aftermath of this incident, insects are entering Japan from the continent every year, and when they land under certain weather conditions, outbreaks occur, with many examples of damage occurring in pastures in the Tohoku region.

[Shigeo Sugi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

昆虫綱鱗翅(りんし)目ヤガ科に属するガ。はねの開張は40ミリメートル内外で、前翅は黄褐色を帯びる。全世界に多数の種を含むキヨトウ（黄夜盗）群の1種。ヨーロッパと北アメリカに産する近縁種armyworm moth／P. unipunctaとともに、イネ、アワ、ムギ、トウモロコシなど各種の農作物の著名な害虫として知られている。本種はアジア一帯のほか、オーストラリア、ニュージーランドにわたって分布する。最近ではむしろ造成牧草地などの被害が注目されている。本種については、中国で行われた広範な成虫個体群の移動に関する研究がよく知られ、1～2月に中国南部で羽化したガは北方に向かい、途中各地で繁殖を続けて中国東北部に達し、秋にはふたたび南下し、この間、計5世代を経るという。この調査ではマーキング法による再捕獲実験も行われた。日本でもこの余波を受けて年々大陸からの進入があり、一定の気象条件のもとで着地したとき大発生が生じ、東北地方の牧草地にその被害例が多い。

［杉　繁郎］

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