Taxonomic history

Xyleborus germanus Blandford, 1894b: 106.

Xylosandrus germanus (Blandford): Hoffman, 1941: 38.

Synonyms

Xyleborus orbatus Blandford, 1894b: 123. Nobuchi, 1981b: 31.

Diagnosis

2.3−2.4 mm long (mean = 2.32 mm; n = 5); 2.3−2.56 times as long as wide. This species can be distinguished by its moderate size; elytral disc gradually curving toward declivity, appearing rounded; posterolateral margins of elytra carinate to interstriae 7; declivital face with six punctate striae; declivital interstriae granulate, uniseriate with erect hair-like setae longer than the width of 1.5 interstriae; pronotum 1.1 times long as wide, pronotum from dorsal view rounded (type 1) and lateral view basic (type 0), summit at midpoint, basal half smooth, shining, sparsely minutely punctate; and sparse mycangial tuft on the pronotal base.

Xylosandrus germanus is nearly identical to X. eupatorii and is most easily distinguished by the pronotum 1.1 times as long as wide and the pronotal base with more abundant and denser setae, and from X. metagermanus by the smaller, shallower strial punctures and feebly impressed striae.

May be confused with

Anisandrus dispar, A. maiche, A. paragogus, Xylosandrus dentipennis, X. eupatorii, and X. metagermanus

Distribution

China (Anhui, Chongqing, Fujian, Guangdong, Guizhou, Guangxi, Hainan, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shanxi, Sichuan, Xizang, Yunnan, Zhejiang), Taiwan, Vietnam. Also present in Japan, Korea, Russia (Far East, Sakhalin, Kurile Is.). Introduced to and established in Europe and Turkey, USA (including Hawai’i) and Canada (Gomez et al. 2018a). The record in Dole and Cognato (2010) from Thailand is incorrect. The cited specimens belong to the closely similar species, Xylosandrus eupatorii.

Host plants

polyphagous (Weber and McPherson 1983b, Dole and Cognato 2010)

Remarks

The basic biology is described by Nobuchi (1981b), Weber and McPherson (1983a), and Ranger et al. (2016). Peer and Taborsky (2004, 2005) have studied male dispersal, variations in sex ratio, and outbreeding depression in the species. Ito et al. (2008) discuss the genetic structure of Japanese populations. Although usually attacking stressed trees, the species sometimes attacks apparently healthy and newly transplanted trees and shrubs (e.g. Nobuchi 1981b, Ranger et al. 2010, 2015). Ranger et al. (2016) discuss the ecology and management of the species in ornamental plant nurseries in USA.

DNA data

Sequences available for COI and CAD.

COI: GU808713GU808714MN620089MN620090MN620091MN620092MN620093

CAD: GU808634GU808635MN620346MN620347MN620348MN620349MN620350MN620351