Aculus Keifer, 1959

Stalažs, Arturs & Turka, Ināra, 2019, Eriophyoid mites (Acari: Prostigmata: Eriophyoidea) of Latvia: an annotated checklist, Zootaxa 4629 (2), pp. 211-236 : 225-227

Genus: Aculus Keifer, 1959

Aculus fockeui (Nalepa & Trouessart, 1891)

Type data. Prunus domestica L. ( Rosaceae ); France.

Host plant records from Latvia. Cultivated plums ( Rosaceae ).

Relation to plant host. Vagrant, cause leaf distortions ( Skoracka et al. 2005).

Bibliographical records from Latvia. Aculus fockeui — Rupais 1976 a, 1976b, 1999 ; Rupais et al. 2014; Stalažs 2014; Phyllocoptes fockeui — Eglītis 1958 ; Ozols 1963; Spuris 1966; Priedītis 1971b; Spuris 1974; Vasates fockeui — Birzgale 1961, 1963 ; Ozols 1973.

Distribution in Latvia. No specific data available. Therefore, most likely to be sporadically associated with the distribution of the host plant. Rupais (1976b) reported this mite species as rare. So far, it has not been problematic in plum orchards in Latvia, with the exception of 1957 and 1958 when outbreaks were observed ( Ozols 1963). Only recently, in experimental orchards of Institute of Horticulture (Dobele municipality), abnormalities typical for Aculus fockeui , and some severely damaged young Prunus domestica plants infested with mites were observed in 2013 and 2014 (A. Stalažs 2013, 2014, personal observation).

Remarks. Host plants reported as “other deciduous trees” by Priedītis (1971b) and Ozols (1973) seem doubtful. However, in Poland this species was also reported from Corylus avellana ( Skoracka et al. 2005) .

Aculus fraxini (Nalepa, 1894)

Type data. Fraxinus excelsior L. ( Oleaceae ); Austria.

Host plant records from Latvia. Fraxinus excelsior L. ( Oleaceae ).

Relation to plant host. Vagrant ( Rupais 1976 a, 1999).

Bibliographical records from Latvia. Vasates fraxini — Rupais 1976b

Distribution in Latvia. Rupais (1976b) reported this species as rare.

Remarks. Saars (1930) listed this name as Phytoptus fraxini with information about collected galls (deformed flowers) from Fraxinus [ excelsior ]. Most likely the record by Saars (1930) is Aceria fraxinivora (Nalepa, 1909) rather than Aculus fraxini (Nalepa, 1894) because such galled flowers of ash trees are only characteristic of Aceria fraxinivora ( Rupais 1999) and Aceria fraxiniflora (Felt, 1906) . The latter species was only recently detected in Hungary and infests introduced North American species of Fraxinus ( Korda et al. 2019) .

Initially, Rupais (1979 b) reported A. fraxini as rare for the fauna of Latvia. In the same year, Rupais (1976a) also reported this species for the fauna of Lithuania. In 1999, he reported Aculus fraxini for Lithuania and as possible for Latvia. Aculus fraxini is included in this current checklist but this is subject to confirmation. Based on the information contained in Rupais’ (1976b), we believe that Rupais (1976a) mistook the word “ Latvia ” for “ Lithuania ”, as this work was dealt with all Baltic countries, including Latvia and Lithuania. This same mistake was reprinted in the last work prepared by Rupais (1999), which was a new edition of the publication from 1976a, and was especially prepared for the fauna of Latvia.

Aculus hippocastani (Fockeu, 1890)

Type data. Aesculus hippocastanum L. ( Sapindaceae ); France.

Host plant records from Latvia. Aesculus hippocastanum L. ( Sapindaceae ).

Relation to plant host. Gall-making, brown erineum at vein angles on leaves ( Rupais 1999; Skoracka et al. 2005).

Bibliographical records from Latvia. Aceria hippocastani — Shevchenko & Rupais 1964 ; Rupais 1981, 1999; Aculus hippocastani — Rupais et al. 2014 ; Eriophyes hippocastani — Eglītis 1956 ; Rupais 1959 a, 1962; Vasates hippocastani — Rupais 1976 a, 1976b .

Distribution in Latvia. Rupais (1981) reported this species as rare.

Remarks. Rupais (1999) described the plant abnormalities as galls at the vein angles on leaves of Aesculus hippocastanum . A local entomologist (V. Petrova 2013, pers. communication) pointed out that the specific galls on leaves of A. hippocastanum , as mentioned by Rupais (1999), have never been seen. However, dense populations of eriophyoid mites, which are yet to be identified to species level, have often been observed under the bud scales during winter (V. Petrova 2013, pers. communication).

Aculus magnirostris (Nalepa, 1892)

Type data. Salix × fragilis L. ( Salicaceae ); Austria.

Host plant records from Latvia. Salix sp. ( Salicaceae )

Relation to plant host. Refuge-seeking ( Skoracka et al. 2005).

Bibliographical records from Latvia. Vasates magnirostris — Rupais 1976b .

Distribution in Latvia. Rupais (1976b) reported this species as rare.

Aculus schlechtendali (Nalepa, 1890)

Type data. Malus pumila Mill. (Rosaceae) ; Germany.

Host plant records from Latvia. Cultivated apples, Malus × domestica Group. ( Rosaceae )

Relation to plant host. Vagrant ( Skoracka et al. 2005).

Bibliographical records from Latvia. Emel′ânov and Petrov (1975) listed this species only under the common name for Aculus schlechtendali in Russian. Mites were found overwintering on short apple twigs; Acheles schlechtendali — Kuznecov & Petrov 1979 ; Aculus schlechtendali — Rupais 1976b ; Stalažs 2014; Phyllocoptes schlechtendali — Eglītis 1958 ; Čakstiņa 1965; Priedītis 1971a; Priedītis & Plīse 1975; Priedītis 1995.

Distribution in Latvia. No data available. Rupais (1976b) reported this species as rare.

Aculus tetanothrix (Nalepa, 1889) Type data. Salix × fragilis L. ( Salicaceae ); Austria. Host plant records from Latvia. Salix alba L., Salix caprea L., Salix cinerea L. ( Salicaceae ). Relation to plant host. Gall-making, leaf-margin rolling and minute galls ( Skoracka et al. 2005). Bibliographical records from Latvia. Aceria tetanothryx — Rupais 1976b ; Eriophyes tetanothrix — Eglītis 1956 ; Bērziņš 1970b. Distribution in Latvia. Rupais (1976b) reported this species as rare.

Aculus xylostei (Canestrini, 1892)

Type data. Lonicera xylosteum L. ( Caprifoliaceae ); Italy.

Host plant records from Latvia. Lonicera xylosteum L. ( Caprifoliaceae ).

Relation to plant host. Vagrant ( Skoracka et al. 2005).

Bibliographical records from Latvia. Aceria xylostei — Rupais 1976 a, 1976b, 1999 ; Plīse 2007; Aculus xylostei — Rupais et al. 2014 ; Stalažs 2014; Eriophyes xylostei — Eglītis 1956 ; Rupais 1962, 1964; Shevchenko & Rupais 1964.

Distribution in Latvia. Reported as common by Rupais (1976b,, 1999).