Genus: Phytoptus Dujardin, 1851

Phytoptus avellanae Nalepa, 1889

Type data. Corylus avellana L. ( Betulaceae); Austria.

Host plant records from Latvia. Corylus avellana L., Corylus cornuta Marshall (Betulaceae) .

Relation to plant host. Gall-making (bud galls) (Rupais 1999; Skoracka et al. 2005).

Bibliographical records from Latvia. Eriophyes avellanae — Eglītis 1956, 1957; Rupais 1959 a, 1962, 1964; Spuris 1966, 1974; Namatēva 2007; Phytoptus avellanae — Shevchenko & Rupais 1964; Bērziņš 1970b; Rupais 1976 a, 1976b; Sekerskaâ 1982; Rupais 1999; Plīse 2007; Rupais et al. 2014; Stalažs 2014.

Distribution in Latvia. A frequently abundant species found in gardens, parks and amenity plantings (Rupais 1964, 1976 a, 1976b).

Phytoptus tetratrichus (Nalepa, 1890), s. l.

Syn. Phytoptus stenoporus (Nalepa, 1918)

Type data. Tilia platyphyllos Scop. (Malvaceae); Austria.

Host plant records from Latvia. Tilia cordata Mill., Tilia ×europaea L., Tilia platyphyllos Scop. (Malvaceae) .

Relation to plant host. Gall-making, erineum and leaf-margin rolling (Rupais 1999; Skoracka et al. 2005).

Bibliographical records from Latvia. Eriophyes tetratrichus — Eglītis 1956; Rupais 1959 a, 1959c, 1960b, 1962; Phytoptus stenoporus — Shevchenko & Rupais 1964; Bērziņš 1968; Rupais 1976a; Rupais 1999; Plīse 2007; Rupais et al. 2014; Phytoptus tetratrichus — Rupais 1964; Shevchenko & Rupais 1964; Bērziņš 1968; Rupais 1976 a, 1976b, 1999; Plīse 2007; Rupais et al. 2014.

Distribution in Latvia. Frequently abundant species (Rupais 1976 a, 1976b).

Remarks. It is noted that Phytoptus tetratrichus (Nalepa, 1890) is quite a variable species which causes varying damage symptoms. It requires additional research using molecular analysis (Soika & Kozak 201 1).