A new species in the genus Phyllocoptes Nalepa (Eriophyidae) from greenhouse roses in Poland

A BSTRACT — A new eriophyid mite species in the Phyllocoptinae, namely Phyllocoptes resovius n. sp. , is described from Rosa hybrida ’Whisky Mac’ (Rosaceae) from Poland. This vagrant species was collected in a greenhouse rose production system and causes malformation and stunted plant growth. It is the ﬁfth species in the Phyllocoptes genus reported from roses. Symptoms caused by P. resovius are compared with those caused by the other species.


INTRODUCTION
The genus Rosa (Rosaceae) comprises around 100 wild species distributed mainly throughout the Northern Hemisphere and several thousand cultivars worldwide (Gu and Robertson 2003). The modern cultivars of Rosa hybrida L. result from a long history of interspecific hybridizations, specially between European tetraploids and Asian diploid species, having as ancestor Rosa gallica L. (El Mokadem et al. 2000, Crespel andGudin 2003). Hybrid roses are recognized highly valuable for economical benefits, being the best source of raw material to be used in agro-based industry, especially in the cosmetics and perfumery (Butt 2005). Today roses are among the most important ornamental plants worldwide. Internationally, the cut flower industry, of which rose accounts for two thirds, exceeds US$ 40 billion per year (Hoy 2013).
Up to date, 19 eriophyoid species belonging to ten different genera have been found on roses worldwide (E. de Lillo and J.W.Jr. Amrine, unpubl. databases, Druciarek and Lewandowski 2016, Ji-Wei et al. 2015, Kamali et al. 2015. The genus Phyllocoptes Nalepa on roses is represented by four species and two among them are considered economically important pests. In the USA, serious damages are caused by Phyllocoptes fructiphilus Keifer, 1940, which is responsible for rose rosette virus (RRV) transmission on roses growing in natural environments as well as in parks and gardens. RRV is the causal agent of rose rosette disease (RRD), the most damaging rose disease in North America, that poses a major threat to the rose industry and homegrowers alike (Laney et al. 2011, Amrine 2014, Di Bello et al. 2015. The second species, Phyllocoptes adalius Keifer, 1939, causes serious injuries on plants cultivated in greenhouses in Europe, where mites can rapidly establish populations and stunting their growth, causing leaf drop and malforma-tion of flowers (Druciarek et al. 2014). Roses being cultivated for millennia, are nowadays the top popular flowering plants in the world and therefore finding a new rose pest in greenhouse production in Europe is an important fact for growers.
The aim of this paper is to describe a new Phyllocoptes species, namely Phyllocoptes resovius n. sp., found in a greenhouse rose production system in Poland. Here we present morphometric data, drawings and scanning electron microscopy (SEM) images of this new vagrant eriophyid mite. In addition symptoms caused by the new species are compared with those caused by P. adalius.

MATERIALS AND METHODS
Rose samples (leaves and shoots) were collected from greenhouse rose (Rosa hybrida L. 'Whisky Mac' Rosen Tantau, Germany) production systems in south-eastern Poland (near the city Rzeszów) in December 2014, and March and May 2015. More than 1200 specimens of the new species from these samples were collected through direct examination under a stereomicroscope Olympus SZX7, and mounted on slides in a modified Berlese medium (Amrine and Manson 1996). Specimens were studied using a phase-contrast microscope Olympus BX41 associated with digital camera (ColorView IIIu and Cell D Soft Imaging System) connected to a computer. The morphological terminology, systematic classification and abbreviation used in figures follows Lindquist (1996) and Amrine et al. (2003). All measurements are in micrometres and unless specified otherwise, are lengths. Measurements of mites were made according to Amrine andManson (1996) andde Lillo et al. (2010). Drawings were made according to de Lillo et al. (2010), using a drawing tube attached to a microscope. Initial drafts of drawings were digitalised with computer scanner. Final plates were produced using the Adobe Photoshop Elements 8 and Adobe Illustrator CS6 software. Length of legs was measured from the posterior margin of trochanter to the tip of the tarsus. Positions of leg setae were measured from the proximal margin of the seta-bearing segment. Positions of ventral setae c2, d, e and f on ventral annuli were counted from the first entire ventral annulus after posterior margin of coxae II. The holotype female measurement precedes the corresponding range for paratypes (given in parentheses). For males and immature stages, only the ranges are given. SEM photographs were taken using desktop scanning electron microscope Phenom Pro (Phenom-World BV, The Netherlands), without earlier preparation of studied specimens. Type specimens on microscope slides are stored in two collections: Department of Applied Entomology, Warsaw University of Life Sciences -SGGW and Museum and Institute of Zoology, Polish Academy of Sciences, Warsaw, Poland.
Gnathosoma -23 (23 -26), curved downward, dorsal pedipalpal genual setae d 9 (8 -10), setae ep 3 (3), pedipalp tarsal setae v 3 (2 -3), cheliceral stylets 19 (17 -22). rounded, 7 (5 -8) over the gnathosomal base. Shield pattern: median line only on rear part of shield; at about 2/3 length of shield the line is bifurcated and joined with admedian lines, forming V-shaped mark; at about 2/3 its length there are lines perpendicular or running slightly to the rear and joining with admedian lines. Admedian lines very weak, well seen only in their middle part. The lines are parallel from anterior margin of the shield to about 1/3 of its length, where they are joined by transverse line; from that place admedian lines gradually diverging to rear margin and joined with median lines in 2/3 and at the end of shield length. Submedian lines I slightly sinuate and gradually divergent from anterior margin of the shield to its rear margin. Submedian lines II curved, joined with submedian lines I at their 1/3 length. Median line, middle part of admedian lines and lines joining median and admedian lines strongly covered with waxy secretions. Scapular setae sc tubercles 4 (3 -4), in the inner sides longitudinal, related to body axis and in outer sides a little bit diagonal, located ahead of rear shield margin, 24 (23 -28) apart; sc 21 (18 -22) directed upwards.
Relation to the host plant -Vagrants, mainly on the lower leaf surfaces, as well as on stems and petals, causing malformation and stunted plant growth.
Etymology -The specific name is derived from the Latin name of city Rzeszów -Resovia, close to where the mites were found.
Remarks -Phyllocoptes resovius n. sp. is similar to other Phyllocoptes species (P. adalius, P. chorites Keifer, 1972, P. fructiphilus, P. linegranulatus (Styer, 1974)) inhabiting rose plants (Keifer 1939b, 1940, 1972, Styer 1974. However it can be easily distinguished from the other by composition of microtubercles located on dorsal opisthosoma and waxy secretions. In P. resovius n. sp. microtubercles form four rows through entire opisthosoma, two inner rows are composed of large and two outer of small microtubercles, other microtubercles are placed randomly. In other Phyllocoptes species from rose microtubercles are of small size only, placed randomly on entire opisthosoma and there are no rows or waxy secretions. The most important diagnostic characters of Phyllocoptes species from Rosa sp. are presented in Table 1. Phyllocoptes resovius n. sp. is most similar (in ornamentation of prodorsal shield, numbers of ray on empodium, size and external genitalia and number of ridges on coverflap, shape of microtuber- cles, as well as most of other diagnostic characters) to P. adalius, which is a common eriophyoid pest species in greenhouse rose production (Druciarek et al. 2014, Druciarek et al. 2016). However P. resovius n. sp., aside from composition of microtubercles located on dorsal opisthosoma and waxy secretions covering microtubercles and prodorsal shield, can be distinguished from P. adalius by the length of setae d and e. Values of characters mentioned above are higher for P. resovius (Table 1). We have observed that both species cause similar injuries on infested rose plants under greenhouse conditions. Damages range from initial simple mosaicred discoloration and deformation of leaves, to a severe delayed bud development and stunting of the whole plant. The initial symptoms of leaf discoloration and malformation are especially evident on newly developed leaves that may already harbor hundreds of mites ( Figure 5).
P. resovius n. sp. is the second species with waxy secretions found on rose, after Callyntrotus schlechtendali (Nalepa, 1894), redescribed by Keifer (1939a). However, sculpture of prodorsal shield, shape of microtubercles, opisthosomal rows and waxy secretions, as well as plenty of other morphometric characters (see Table 1) clearly differentiate C. schlechtendali from the new species.