Moths of North Carolina
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Phyllonorycter Members:
3 NC Records

Phyllonorycter salicifoliella (Chambers, 1875) - Willow Leaf Blotch Miner Moth

Taxonomy
Superfamily: Gracillarioidea Family: GracillariidaeSubfamily: LithocolletinaeP3 Number: 330326.00 MONA Number: 791.00
Comments: Phyllonorycter is a genus of small and often colorful moths, with 79 described species in North America. The larvae of most form underside tentiform mines on woody plants and pupate within the mines.
Identification
Field Guide Descriptions: Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Davis and Deschka (2001)Technical Description, Immature Stages: Davis and Deschka (2001)                                                                                 
Adult Markings: Davis and Deschka (2001) provided a comprehensive review of the Salix-feeding Phyllonorycter species and noted that this wide-ranging species exhibits the greatest amount of morphological variation of any North American Phyllonorycter. Variation occurs in both external features and the genitalia and has caused much confusion among workers. As an example, adults that were mostly reared and previously identified as P. salicifoliella by a highly respected and knowledgeable worker on the Gracillariidae contained representatives of five species of Phyllonorycter. Most of the confusion reflects variation in the forewing pattern and male genitalia. The genitalia tend to show normal within-population uniformity but also exhibit conspicuous between-population differences that in some cases may occur between adjacent populations. Genitalia and DNA bar-coding probably provide the most reliable way to identify specimens. The following description is based on Davis and Deschka (2001).

The adults tend to fall into two general types that include a heavily dusted dark form and a much brighter and boldly marked whitish form. The head tuft is rough and has variable mixtures of white and brown scales that are usually mostly white. The antenna has a scape and pedicel that is usually entirely white, but occasionally slightly brownish dorsally. The flagellomeres are variable, but are usually mostly white with a brownish suffusion over the dorsal apex. In some cases they can be mostly brown with whitish basal annulations. The labial palp is either entirely white or with a brownish suffusion ventrally. The dorsum of the thorax is usually white and lightly irrorated with dark brown to fuscous, but sometimes can be mostly reddish brown.

The forewing is slender and golden brownish and usually has five costal and four dorsal white streaks. There is also a dorsal white spot at the base of the wing that can vary from being large and prominent in the lighter forms to greatly reduced in the darker forms. The ground color of the forewing varies from light golden to reddish brown and is variably marked with white streaks and scattered dark brown to fuscous scales. There are five whitish costal streaks, with the basal two the most oblique. These are sometimes indistinct in dark specimens. There is usually a large, white basal spot on the dorsum that in dark specimens may be largely obliterated by reddish brown scales. Four white dorsal streaks are usually present beyond the basal spot. The basal two are the broadest and are sometimes joined to the costal streaks. The outer two streaks are narrower, and the costal and dorsal pairs are often joined, but with the distal-most band usually separated by an elongate, subapical fuscous spot. The termen has a fuscous margin and the fringe is pale gray. The hindwing is uniformly gray, while the legs are generally light fuscous dorsally and become progressively paler on the mid- and hind legs. The apices of the tibial and tarsal segments are white.
Forewing Length: 3-4 mm (Davis and Deschka, 2001)
Adult Structural Features: Davis and Deschka (2001) has detailed descriptions and illustrations of the male and female genitalia.
Immatures and Development: Females attach their flat eggs to the lower leaf surface. A given female normally lays one egg per leaf, but a leaf can have several mines that are the product of two or more females. The first three instars are sap feeders, while the last two switch to consuming parenchyma tissue. The first instar produce a slender, serpentine to wedge-shaped, subepidermal tract on the underside of the leaf that is enlarged by the next two instars to form an oval blotch (Davis and Deschka, 2001). The later instars typically do not enlarge the area of the mine, but simply feed deeper into the leaf tissue. Silk that is spun across the mine causes the mine to pull together to form a tentiform structure with a single longitudinal fold (rarely two or three folds may be evident). The granular frass is collected at one end of the mine and pupation occurs within the mine in a silken cocoon that is often located near the center.
Distribution in North Carolina
Distribution: This species is widely distributed across North America from Mississippi to Ontario in the East and from southern California to northern British Columbia in the West. Populations also have been found in the central Rocky Mountains, the Ozarks, and in the southern Appalachians. As of 2022, we have one verifiable record from Haywood County in the western mountains.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Immature Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Flight Comments: Phyllonorycter salicifoliella appears to be bivoltine in many areas of the range, particularly where populations are found at lower elevations or in the southern portion of the range (Davis and Deschka, 2001). The mines are first produced in July to mid-August, with a second brood mining from late August to November. The adults overwinter and begin flying in May to early June after the spring warm-up.
Habitats and Life History
Habitats: This species is typically associated willow thickets and to a lesser extent poplar stands.
Larval Host Plants: The larvae mostly mine willow leaves, but will occasionally feed on poplars, particularly Balsam Poplar (P. balsamifera) and Quaking Aspen (P. tremuloides). A variety of willows are used (Davis and Deschka, 2001), many of which are found at northern latitudes or in western North America. These include White Willow (Salix alba), Peachleaf Willow (S. amygdaloides), Weeping Willow (S. babylonica), Bebb's Willow (S. bebbiana), Bonpland willow (S. bonplandiana; = laevigata), Carolina Willow (S. caroliniana), Missouri River Willow (S. eriocephala), Arroyo Willow (S. lasiolepis), Yellow Willow (S. lutea), Mountain Willow (S. monticola), Purple Willow (S purpurea), Scouler's willow (S. scouleriana), and Silky Willow (S. sericea). - View
Observation Methods: Local populations are best documented by rearing adults from mines on willows.
Wikipedia
See also Habitat Account for Shoreline Shrublands
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR SU
State Protection:
Comments: This mostly northern species appears to be rare in North Carolina. As of 2022 we have only one verifiable record from a site in Haywood County.

 Photo Gallery for Phyllonorycter salicifoliella - Willow Leaf Blotch Miner Moth

Photos: 7

Recorded by: Ken Kneidel on 2022-10-16
Mecklenburg Co.
Comment: 		Recorded by: Ken Kneidel on 2022-10-16
Mecklenburg Co.
Comment:
Recorded by: Ken Kneidel on 2022-09-25
Mecklenburg Co.
Comment: An occupied mine on Salix nigra; the adult was reared and emerged on October 16. 		Recorded by: Ken Kneidel on 2022-09-25
Mecklenburg Co.
Comment:
Recorded by: Ken Kneidel on 2022-09-25
Mecklenburg Co.
Comment: 		Recorded by: E.J. van Nieukerken & C. Doorenweerd on 2010-10-13
Haywood Co.
Comment: BOLD specimen WOGRA008-13. Mine collected on 2010-09-28; adult emerged on 2010-010-13. CreativeCommons - Attribution Non-Commercial Share-Alike (2012); License Holder: Naturalis, Biodiversity Centre
Recorded by: E.J. van Nieukerken & C. Doorenweerd on 2010-10-13
Haywood Co.
Comment: Mine collected on 2010-09-28; adult emerged on 2010-010-13. BOLD specimen WOGRA010-13. Attribution Non-Commercial Share-Alike (2012); License Holder: Naturalis, Biodiversity Centre.