Moths of North Carolina
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19 NC Records

Podosesia syringae (Harris, 1839) - Ash Borer Moth

Podosesia syringaePodosesia syringaePodosesia syringaePodosesia syringae
Taxonomy
Superfamily:
Sesioidea		 Family:
Sesiidae		Subfamily:
Sesiinae		Tribe:
Synanthedonini		P3 Number:
55a0130		 MONA Number:
2589.00		 Other Common Names:
Lilac Borer Moth, Lilac/Ash Borer, Lilac Clearwing Borer, Ash Clearwing Borer
Comments: Of the 136 or more members of the Sesiidae that occur in North American north of Mexico, 37 have been recorded in North Carolina. Some sesiids, known broadly as clearwing borers, are significant pests of commercial crops. The great majority are mimics of wasps and hornets. Podosesia syringae is one of two species of Podosesia found in the state, and both utilize ashes (Fraxinus spp.) as a food plant.
Identification
Field Guide Descriptions: Covell (1984); Beadle and Leckie (2018)Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Eichlin and Duckworth (1988)Technical Description, Immature Stages: Solomon (1975)                                                                                 
Adult Markings: Podosesia syringae resembles a paper wasp. The thorax is brownish-black with red scales scattered above the base of wings and immediately adjacent to the abdomen. The abdomen is brownish-black and is constricted at the base in males. The anal tuft is brownish-black and pointed, while the forewing is brownish-black except for a small hyaline area at the base where there is red on the margins. The hindwing is hyaline with narrow, black margins. The terminal half of the legs are yellow, and the proximal half mixed with red, yellow, and black. The hindlimb is very long and is dangled beneath the body as the moth flies in a slow, hovering flight that resembles that of a paper wasp. The following detailed description of the male is mostly from that of Purrington and Nielson (1977) and Eichlin and Duckworth (1988).

The antenna is orange to reddish-orange and blackened on the apical third, while the labial palp is roughened, orangish-red above, and black below. The vertex of the head is silver gray and the front grayish-brown, with the occipital fringe (collar) orangish-red. The thorax is brownish-black and often strongly powdered with chestnut-red on the sides, above the wing base, and on the posterior margin of the mesothorax. There is a yellow spot beneath the wing base and a small patch of yellow laterally on the posterior margin of the metathorax. The abdomen is constricted somewhat at the base and mostly brownish-black, with reddish scaling often on segments 2 and 3 above. The anal tuft is pointed and black. The legs are marked with black, orange and yellow from the fibia to the tarsus. The hindleg is unusual in having the first tarsal segment very long, and about as long as the tibia. The first segment is yellow, with brownish-black on the apical half, while the other tarsal segments are yellow and much shorter. The forewing is opaque except for hyaline areas at the base. It is mostly brownish-black above with red basally on the margins. The hindwing is mostly hyaline, with the veins, fringe, and discal spot brownish-black. The wing margin is variously suffused with brownish-black and lightly powdered with orange. The females are similar to the males but without the noticeably constricted abdomen. Specimens toward the southern portion of the range have increasingly more rust red, especially on the thorax and abdominal segments two and three.

Podosesia aureocincta closely resembles the dark, typical, color form of P. syringae as described above and that occurs in the eastern US. Both are mimics of Polistes paper wasps. These two sibling species can be distinguished by the morphology of the eggs, the number of crochets on the proleg of the sixth abdominal segment of the last instar of the larvae, the flight season, and banding on the abdomen (Purrington and Nielson, 1977). The adults of both sexes of P. aureocincta have a distinctive orange-yellow band on abdominal segment 4 that is absent on the dark morph of P. syringae. In addition, local populations that are sympatric fly at different times of the year, with P. syringae typically flying in April-July in North Carolina and P. aureocincta in August and September.
Wingspan: 24-32 mm for males and 28-35 mm for females (Solomon, 1975).
Forewing Length: 10-17 mm (Brown and Mizell, 1993).
Structural photos
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae are borers that feed primarily on ashes, particularly Green Ash and American Ash. Adult emergence occurs in association with the spring warm-up and leaf-out, and varies depending on the latitude and climatic conditions. Forbes (1911) studied this species in Illinois where the larvae attack Green Ash and reported that the females lay their eggs in masses on rough, scarred, or knotty places on the trunk or branches. The hatchlings emerge in about six days and eat through the bark into the outer layers of the sapwood where they make irregular galleries. They are capable of penetrating the harder wood, and eventually make their way to the center of small branches. In fall, the nearly mature or mature larvae bore towards the bark surface and construct a hibernating cell by plugging up the burrow on both ends with frass. The larvae feed minimally in the spring before pupating in April or the first part of May in a burrow that leads to the outer edge of the bark, where they leave a thin outer film that serves as an escape hatch. At emergence, the pupa penetrates the film and projects out of the bark, with the adult emerging shortly thereafter. The moths make their appearance from the latter part of April to the middle of June in central and northern Illinois.

Solomon (1975) conducted a comprehensive study in Mississippi where the larvae also attack Green Ash. The adults emerged during the day from early-morning until around noon, with the females mating within an hour or two after emerging. Females began ovipositing within an hour after mating and deposited eggs singly or in small clusters, mostly in bark crevices or beside bark ridges. Captive females laid 204-586 eggs (mean = 395) over 2-9 days, with hatchlings in the field emerging after 9-13 days. Larvae bored into the bark, and left holes with sap and frass oozing from them. The larvae initially mined the phloem-cambium area vertically, then bored into the sapwood for a long distance before boring back to the bark surface. The completed galleries were 7-32 cm long, and pupation occurred in a plugged section of a gallery that extended almost to the bark surface except for a paper-thin cover. The larva is white except for an amber-colored head, thoracic shield, and spiracles. Newly hatched larvae average ca. 1 mm in length and reach 26-34 mm at maturity. The pupa is reddish brown and 18-24 mm long (Solomon, 1975). Larvae in Solomon’s (1975) study emerged from March through July. The adults mostly attacked the lower trunk and preferred trees in open settings. Woodpeckers fed heavily on the larvae during the winter and probably play a significant role in controlling population sizes.
Larvae ID Requirements: Identifiable from close inspection of specimens or by DNA analysis.
Distribution in North Carolina
Distribution: Podosesia syringae is widely distributed across North America, with the range including almost all of the eastern US from the Atlantic Coast states to the Great Plains, much of southern Canada from British Columbia eastward to Nova Scotia, and more spottily in non-arid regions of the western states. In the eastern US, the range extends from Maine southward to northern Florida, and westward to eastern Texas, central Oklahoma, eastern Kansas, eastern Nebraska and Minnesota. This species occurs statewide in North Carolina.
County Map: Clicking on a county returns the records for the species in that county.
Podosesia syringae
Flight 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: Adults have been observed from January through September in different areas of the range, with a seasonal peak typically from May through July. As of 2024, our records are from late-April through mid-July. Local populations are univoltine in North Carolina, with populations in the Coastal Plain and Piedmont flying in April and May, and those in the Blue Ridge 3-4 weeks later.
Habitats and Life History
Habitats: Local populations occur in rural, urban, and forested areas where ashes or other host plants are present.
Larval Host Plants: The larvae feed on members of the Oleaceae (Forbes, 1911, 1923; Seaver, 1916; Engelhardt 1946; Peterson, 1964; Baker, 1972; Solomon, 1975). They are a major pest of Green Ash (Fraxinus pennsylvanica) both in the wild and where they are used as shade trees or nursery stock. They can also cause significant losses to Lilac (Syringa vulgaris) that is grown in nurseries. Other documented hosts include Fringetree (Chionanthus virginicus), American Ash (F. americana), Carolina Ash (F. caroliniana), Black Ash (F. nigra), various European and red ashes, a Ligustrum sp. (privet) and ornamental plantings of olive (Olea europaea). Forbes (1911) reported them to feed on American Mountain-ash (Sorbus americana) in the Rosaceae, but this needs additional verification. - View
Observation Methods: The adults are diurnally active and are not attracted to lights, but frequently visit flowers. They are most easily collected by employing synthetic pheromone traps (see Taft et al., 2004, for a list of species-specific pheromone blends).
Wikipedia
Status in North Carolina
Natural Heritage Program Status: [W-Th]
Natural Heritage Program Ranks: GNR [S2S3]
SPE: 0
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: This species closely mimics a Polistes paper wasp in both appearance and behavior. P. syringae does not pose a serious threat to ash trees in North Carolina given the prevalence of Fraxinus in the state. However, the arrival of the Emerald Ash Borer beetle (Agrilus planipennis) in the state in 2013 could potentially impact populations of P. syringae in the future due to the widespread loss of ash trees statewide.

 Photo Gallery for Podosesia syringae - Ash Borer Moth

Photos: 6

Recorded by: vito_fandozzi on 2022-06-09
Henderson Co.
Comment: iNat: (CC BY-NC) (cropped)		Recorded by: Richard Teper on 2021-04-27
Orange Co.
Comment:
Recorded by: Jim Petranka and Becky Elkin on 2019-05-25
Madison Co.
Comment: 		Recorded by: Jim Petranka and Becky Elkin on 2019-05-25
Madison Co.
Comment:
Recorded by: Jim Petranka and Becky Elkin on 2019-05-25
Madison Co.
Comment: 		Recorded by: J.B. Sullivan on 2017-06-06
Ashe Co.
Comment: