Taxonomic information	Current valid scientific name: Calepitrimerus baileyi (Keifer, 1938) Synonyms: Phyllocoptes aphrastus (Keifer, 1940) Name used in the EU legislation: – Order: Acarina Family: Eriophyidae Common name: Bailey's rust mite, apple rust mite Name used in the Dossier: –
Group	Mites
EPPO code	CALEBA
Regulated status	The pest is not regulated in the EU, neither is on any EPPO list, but it is present in EPPO database.
Pest status in Turkey	The pest is reported in Turkey in Erzurum (Alaoglu, 1984), Tokat (Yanar and Ecevit, 2005), Van Lake Basin: Iskele, Gürpinar, Edremit on Malus pumila Mill., M. sylvestris Mill., M. communis L. (Rosaceae). New records: Ankara, Van‐Ahlat, Iskele on Malus pumila Mill., M. sylvestris Mill., M. communis L. (Denizhan and Çobanoǧlu, 2010), Yalova, Armutlu (Denizhan, 2018).
Pest status in the EU	Present in Poland and Greece (Fauna Europaea; GBIF; De Lillo, Amrine. 1998).
Host status on Malus domestica	Malus domestica is a host of the pest and the species can complete its life cycle on this host (Abou‐Awad et al., 2011); however, another author wrote that this species is vagrant and that the mites survive on the leaves (Denizhan, 2018). The pest status is confirmed also by others authors (Abou‐Awad et al., 2011; Jeppson et al., 1975; Momen & Lamlom, 2021).
PRA information	No PRA is available for C. baileyi.
Other relevant information for the assessment
Biology	C. baileyi is able to develop successfully from egg to adult at temperatures between 23°C and 35°C, and 65% RH. It has two nymphal stages, each followed by a resting stage, before reaching adulthood. The duration of egg (incubation period), first instar nymph, nymphochrysalis, second instar nymph, imagochrysalis, pre‐oviposition and post‐oviposition decreases as temperature increases. The oviposition duration decreases with increasing temperature, specifically it goes from an average of 24–22 days with temperatures ranging from 23°C to 35°C. Most of the eggs are laid alongside the midrib or veins of the leaf. Females deposit between 12 and 23 eggs with temperatures ranging from 23°C to 35°C. The total life cycle is completed after 9.7 to 5.3 days depending on sex (i.e. males develop faster) and temperature (23–35°C) (Abou‐Awad et al., 2011). In Egypt, population dynamics of C. baileyi was affected by climatic conditions and about 11 generations were recorded per year (Abou‐Awad et al., 2011).
Symptoms	Main type of symptoms	Mite feeding causes browning on the underside of apple leaves, partial defoliation, rolled and distorted leaves russet on fruit and delays or inhibits plant apical growth (Creelman, 1971; Abou‐Awad et al., 2011).
	Presence of asymptomatic plants	In early September, C. baileyi deutogynes hibernate mainly in small, permanently dormant buds and under the loose bark of spurs and around buds on 1‐year‐old shoots, and move into fruiting buds between the shoot and the pink bud stages and in vegetative buds when the buds have started to swell (Abou‐Awad et al., 2011). The deutogyne will seek refuge for aestivating and/or overwintering (e.g. under tree bark scales) until early spring when it begins laying eggs that develop into protogynes (Beaulieu and Knee, 2014).
	Confusion with other pests	The two conspecific morphs (deutogyne and protogynes) may be wrongly assigned to different species or even genera (Jeppson et al., 1975), although the forms can generally be correctly associated with each other with experience and good sample sizes (Beaulieu and Knee, 2014). There is a single sequence in GenBank of a specimen collected on Malus domestica (Calepitrimerus baileyi voucher MAL91.3 large subunit ribosomal RNA gene, partial sequence, ACCESSION MW633874) (visited on 10.29.21, can help with diagnosis. Calepitrimerus mathiasrexi is similar in morphology to Calepitrimerus baileyi and Calepitrimerus cariniferus Keifer (Keifer, 1938; Baker et al., 1996; Amrine et al., 2003), with microscopic differences (Ripka, 2010).
Host plant range	Malus pumila Mill., M. sylvestris Mill., M. communis L. (Rosaceae) (Denizhan & Çobanoǧlu, 2010; Creelman, 1971).
Reported evidence of impact	Partial defoliation can reduce the productivity of the plants (Abou‐Awad et al., 2011; Creelman, 1971).
Pathways and evidence that the commodity is a pathway	The most possible way to spread is through the introduction of plant materials, as the mite can be found in buds, even in resting ones. There is no reference in the literature regarding the possibility fruit being a pathway. There are no data on the active dispersal capacity of the pest.
Surveillance information	No surveillance information is currently available from the Turkey NPPO for Calepitrimerus baileyi