Taxonomic history

Phloeotrogus crassiusculus Motschulsky, 1866: 403.

Xylosandrus crassiusculus (Motschulsky): Wood, 1977a: 68.

Synonyms

Xyleborus semiopacus Eichhoff, 1878b: 334. Wood, 1969c: 119.

Xyleborus semigranosus Blandford, 1896b: 211. Schedl, 1959a: 496.

Dryocoetes bengalensis Stebbing, 1908b: 12. Beeson, 1915b: 297.

Xyleborus mascarenus Hagedorn, 1908: 379. Eggers, 1923a: 130.

Xyleborus ebriosus Niijima, 1909: 154. Choo, 1983: 98.

Xyleborus okoumeensis Schedl, 1935f: 271. Schedl, 1959a: 496.

Xyleborus declivigranulatus Schedl, 1936j: 30. Schedl, 1959a: 496.

Diagnosis

2.3−2.9 mm long (mean = 2.58 mm; n = 5); 2.17−2.42 times as long as wide. This species is distinguished by the moderate to large size; elytral disc gradually curving toward declivity, appearing rounded; posterolateral margins of elytra carinate to interstriae 7; declivital face with 6 striae; interstriae and striae granulate, confused, appearing dull, with erect hair-like setae longer than the width of two interstriae; pronotum as 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 dense mycangial tuft on the pronotal base.

May be confused with

none

Distribution

Circumtropical. Within the study region recorded from Bhutan, Cambodia, China (Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Hong Kong, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Shanghai, Sichuan, Xizang, Yunnan, Zhejiang), India (Andaman Is, Arunchal Pradesh, Assam, Himachal Pradesh, Karnataka, Meghalaya, Sikkim, Tamil Nadu, Uttarakhand, West Bengal), Laos, Myanmar, Nepal, Taiwan, Thailand, Vietnam. Also present in Korea. Imported to and established in Europe, North, Central, and South America (Kirkendall and Ødegaard 2007, Pennacchio et al. 2003, Flechtmann and Atkinson 2016, Landi et al. 2017, Gallego et al. 2017, Gomez et al. 2018a).

Host plants

strongly polyphagous (Dole and Cognato 2010)

Remarks

The basic biology has been described by Browne (1961a), Schedl (1963a) (both as Xyleborus semiopacus), and Ranger et al. (2016), amongst others. Flight activity and the attraction of flying adults to ethanol has been studied in the southern USA by Reding et al. (2011, 2013), attack densities and adult emergence on various hosts by Mayfield et al. (2013), and attraction to volatiles from the symbiotic ambrosia fungus by Hulcr et al. (2011). This is a species of economic importance because, like Xylosandrus compactus, it can attack and breed in healthy shoots and twigs. This can result in the introduction of pathogenic fungi (Sreedharan et al. 1991, Davis and Dute 1997). It seems to be an infrequent pest in the Oriental and Afrotropical regions, although attacks on transplants have been recorded (e.g. Browne 1968a). It is of greater importance in the USA, where its ecology and management in plant nurseries is discussed by Ranger et al. (2016).

DNA data

Sequences available for COI and CAD.

COI: GU808708; GU808709; GU808710; GU808711; MN620070; MN620071; MN620072; MN620073; MN620074;MN620075;MN620076;MN620077;MN620078

CAD: GU808630; GU808631; GU808632; GU808633; MN620331; MN620332; MN620333; MN620334; MN620335; MN620336; MN620337; MN620338; MN620339; MN620340