Plagiotrochus kunugiphagus (Ide & Abe, 2015)

Dryocosmus kunugiphagus Ide & Abe, 2015: 469, ♂ ♀ & ǒ.

Plagiotrochus kunugiphagus (Ide & Abe) Pujade-Villar et al. (2020a: 1215), ♂ ♀ & ǒ.

Distribution. Japan (Honshu, Kyushu, Shikoku) (Mukaigawa 1914: 487; Mukaigawa 1922: 203; Monzen 1929: 349; Shinji 1944: 67 (photo 113); Yukawa & Masuda 1996: 133, 134; Ide & Abe 2015: 476) and Korean Peninsula (Saito 1932: 101; Yukawa & Masuda 1996: 133, 134; Pujade-Villar et al. 2020a: 1215).

Remarks. The alternating lifecycle was reported by Mukaigawa (1914) and Yukawa & Masuda (1996). The sexual and asexual generations were described by Ide & Abe (2015).

Remarks (2). Plagiotrochus kunugiphagus was erroneously identified as Andricus inflator Hartig, 1840, a species described from Europe, based exclusively on the morphology of the galls (Monzen 1929, 1938; Shinji 1944; Ishii 1949; Sakagami 1952; Inoue 1960). Although the galls of both species are quite similar, the adult wasps are morphologically very different (Ide & Abe 2015).

Remarks (3). The host plants of P. kunugiphagus are Q. acutissima and, occasionally, Q. variabilis (both section Cerris) in Korea, according to the original description and Pujade-Villar et al. (2020a). However, photos 136 and 233 in Shinji (1944) belong to a different oak species ( Q. serrata = Q. glandulifera; sect. Quercus). Therefore, it is necessary to confirm the host plant.

Remarks (4). In Mukaigawa (1914), this species was mentioned as ‘Kunugi-no-ibo-fushi-bachi’ and in Mukaigawa (1922), as ‘Kunugi-ibo-fushi-bachi’.

Remarks (5). Yukawa & Masuda (1996) photographed the asexual gall of this species and described it as ‘Kunugi-eda-tama-fushi’ (C-076), and the sexual gall as ‘Kunugi- waka-me-maru-zui-fushi’ (C-079). Later, Ide & Abe (2015) identified these galls as belonging to their newly described species, D. kunugiphagus .

Biology. Both generations induce twig galls, presumably on Q. acutissima and Q. variabilis (sect. Cerris) (see Remarks 3 above) (Table 1; Ide & Abe 2015). More detailed information on the biology of this species is summarized in Pénzes et al. (2018) under the name Dryocosmus kunugiphagus .