Agrilus cuprescens, (MENETRIES)

Westcott, Richard L., Looney, Chris & Asche, Megan, 2015, Agrilus cuprescens (Ménétries) (Coleoptera: Buprestidae), the Rose Stem Girdler, Discovered in the State of Washington, with Comments on Host Plant Associations, The Coleopterists Bulletin 69 (2), pp. 275-279 : 275-278

AGRILUS CUPRESCENS (MÉNÉTRIES) ( COLEOPTERA : BUPRESTIDAE ), THE ROSE STEM GIRDLER, DISCOVERED IN THE STATE OF WASHINGTON, WITH COMMENTS ON HOST PLANT ASSOCIATIONS

RICHARD L. WESTCOTT Plant Division , Oregon Department of Agriculture, 635 Capitol NE Salem, OR 97301, U.S.A. [e-mail]

CHRIS LOONEY Entomology Laboratory , Washington State Department of Agriculture 1111 Washington Street SE Olympia, WA 98504, U.S.A. [e-mail]

AND

MEGAN ASCHE 2008 Evergreen Park Drive SW #211 Olympia, WA 98502, U.S.A. [e-mail]

On 3 June 2014, one of us (MA) noted and photographed a small species of Buprestidae on rose and blackberry leaves in Olympia, Thurston Co., in western Washington. Several images were posted to BugGuide (bugguide.net/node/view/ 116450/), including that used for Fig. 1 . Specimens were sent to the first author who identified them as the adventive Agrilus cuprescens (Ménétries) (rose stem girdler), which was unknown from the state. On 11 June 2014, Jeanne Dammarell found and photographed this species in eastern Washington, on a garden rose in Davenport. She, too, posted images to BugGuide, including that which we use for Fig. 2 . She also found A. cuprescens on raspberries in Colbert, WA soon after.

Agrilus cuprescens is a trans-Palaearctic species with a tortuous taxonomic history ( Jendek 2003) that seems to have been introduced into the USA sometime prior to 1878. Fisher (1928) treated it as Agrilus viridis var. fagi (Ratzeburg) (a misidentification), dating its discovery in the USA as 1923, which some later authors followed. Surely he meant 1913, as Weiss (1914; misidentified as Agrilus politus (Say)) reported on collections of this species from 1913. Weiss (1914) also recorded several species of Rosa L. as larval hosts that Nelson et al. (2008) listed only as adult hosts. Based on observations provided by Weiss (1914) alone, it seems likely that the beetle was already well established in the northeastern USA by 1913. Fisher (1928) cited an even earlier work containing only illustrations ( Glover 1878; misidentified as A. fagi ). Its date of publication and title, “Illustrations of North American Entomology”, suggest that the species was on our continent at least by the late 1870s. Irrespective of whenever it may have established, the beetle has had ample opportunity to spread via commerce and autonomously across an abundant host continuum. Given the economic and cultural importance of roses and Rubus L. spp. (blackberry, raspberry, etc., most of which are hybrids), a significant volume of host material has been repeatedly imported into and moved throughout the USA. The species was known as far west as central Idaho by the 1970s and was first seen in eastern Oregon during 1994 ( Nelson et al. 1996). The only other species of Agrilus Curtis in the Pacific Northwest with which it might be confused are coppery forms of A. politus , a species with hardwood hosts such as willow and maple.

Following the initial discoveries in Washington, we used beating sheets and visual search to survey numerous locations in western and central Washington, detecting adult beetles in two additional counties. We also alerted Master Gardeners to this newly detected pest species. Subsequently, specimens of buprestid larvae in raspberries from elsewhere in eastern Washington were provided to one of us (CL). A complete listing of positive and negative sample localities is given in Table 1. Voucher specimens are deposited in the collections of the first author, the Washington State Department of Agriculture Collection (WSDA) in Olympia and The Maurice T. James Entomological Collection, Washington State University, Pullman.

Hosts of A. cuprescens in the USA have been reported inconsistently, with actual larval hosts not always distinguished from adult plant associations. The catalog by Nelson et al. (2008) is incomplete and misleading: most of the plants ( Rosa spp. ) recorded as larval hosts by earlier authors are treated only as adult collection records, and no species of Rubus was listed in spite of widespread mention in earlier literature. It is therefore worthwhile to provide a summary herein of specific host records we found in the literature, all being larval hosts unless prefaced by “on”, which indicates that adults were merely collected on the plant. Some of these host plants were published in more than one place, but we provide only the earliest references we found. Scientific names of hosts are according to The Plant List (2013). For complete world coverage of host plants for the genus Agrilus and references thereto, see Jendek and Poláková (2014).

Known host records are: Rosa blanda Aiton , R. carolina L., R. glauca Pourret (as R. rubrafolia [sic]), R. multiflora Thunberg , R. nitida Willdenow , R. rugosa Thunberg , and R. setigera Michaux ( Weiss 1914, as A. politus ); R. xanthina Lindley (as R. hugonis Hemsley ; Fisher 1928, as A. viridis var. fagi ); red raspberry varieties ‘Cuthbert’, ‘Latham’ and ‘Viking’ ( Garlick 1940, as A. aurichalceus rubicola Abielle ); “blackberry” leaves ( Nelson et al. 1981, as A. aurichalceus rubicola ); Rosa nutkana C. Presl (as var. hispida Fernald ), R. woodsii ultramontana (S. Watson) R. L. Taylor and MacBryde (as var.) ( Nelson et al. 1996, as A. cupreus Redtenbacher , lapsus calami); Rosa acicularis Lindley and Rosa arkansana Porter ( Larson 2003, as A. aurichalceus Redtenbacher ).

Two new larval host records are: Reared ex dead canes Rubus idaeus L. x ‘Fall Gold’, Oregon, Union Co., Union, 3-13-VI (year uncertain); beaten and swept from sweetbriar rose, Rosa rubiginosa L. (= R. eglanteria L.); Oregon, Union Co., slope W of Ladd Marsh, 5 mi SSE La Grande, and Union, 15-VI-2006, both R. L. Westcott. Larval damage and adult emergence holes were observed at all three collection sites. Voucher specimens are deposited in the Oregon Department of Agriculture Collection, the Oregon State Arthropod Collection, and the collection of the first author. A new adult host record is Rosa pisocarpa A. Gray , Washington, Lewis Co., Chehalis, 46.6271°, − 123.0760°, 16-VI-2014, C. Looney, vouchers in WSDA.

Garlick (1940, as A. aurichalceus rubicola ) reported as hosts black currant, red currant, and gooseberry ( Ribes L.), and Nelson et al. (1981, as A. aurichalceus rubicola ) reported the beetle on Ribes alpinum L. However , those are based on misidentification of another Agrilus species (E. Jendek in litt. to RLW). Thus, the only confirmed larval hosts for A. cuprescens are species of Rosa and Rubus . Adult records from other plant genera undoubtedly are based on specimens of A. cuprescens taken resting on leaves, which is a common habit among species of the genus.

Agrilus cuprescens is an ecological and economic pest. Larson (2003, as A. aurichalceus ) identified the beetle as a serious threat to prairie communities and subsequently discussed the beetle in some detail regarding its occurrence and biology on wild roses in Alberta and Saskatchewan ( Larson 2009). “In southern Saskatchewan and southern Alberta it is very well established and in many places has reduced rose populations to just a fraction of what they were a decade ago. On my ranch roses have gone from being a dominant shrub to virtually absent, and this is the case across the range of habitats occupied by wild roses” (D. J. Larson in litt. to RLW). Wild roses are an important habitat element for invertebrates, birds, and mammals in both grasslands and forests.

Davis and Raghuvir (1964, as A. rubicola communis Obenberger ) stated that the rose stem girdler was the most serious pest of raspberries in Utah. It remains a common concern in the northern part of the state (D. Alston in litt. to RLW). The sample provided to CL through WSU Master Gardeners came from a homeowner who stated it was “destroying my raspberry patch”, and who had dealt with this problem for at least three years. Although we did not detect the beetle in many counties, including Whatcom and Skagit, it is likely only a matter of time before the beetle is found there. The species is poised to become a significant pest in the Pacific Northwest, where cane fruit is a major agricultural commodity.

Figures

Figs. 1–2. Agrilus cuprescens, adults on garden rose. 1) Olympia, Washington, 3 June 2014, photograph by Megan Asche; 2) Davenport, Washington, 11 June 2014, photograph by Jeanne Dammerall.