Pachypsylla celtidisumbilicus
Riley, 1890
Hackberry Disc Gall Psyllid
Pachypsylla celtidisumbilicus is a of hackberry that produces distinctive disc-shaped galls on hackberry leaves (Celtis spp.). emerge in fall and seek shelter to overwinter, often becoming household nuisances when they congregate on building exteriors. The species is one of at least seven Pachypsylla species associated with hackberry in North America, each producing a characteristic gall .
Pronunciation
How to pronounce Pachypsylla celtidisumbilicus: /ˌpækɪˈsɪlə sɛlˌtɪdɪsˈʌmbəlɪkəs/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Produces disc or button-shaped galls on the upper surface of hackberry leaves, in contrast to the nipple galls formed on leaf undersides by Pachypsylla celtidismama. Gall shape, size, and location on the leaf are the primary means of distinguishing this from . are small (3.5–4.5 mm), resemble tiny cicadas, and have beak-like .
Images
Habitat
Associated with hackberry trees (Celtis spp.), both in natural stands and ornamental plantings. overwinter in concealed locations including crevices in tree bark, building siding, window frames, and door frames.
Distribution
Ranges throughout the natural and planted distribution of hackberry in North America.
Seasonality
emerge in fall (September–October), seek shelter, and become active again in spring when they oviposit on newly unfolding hackberry leaves.
Host Associations
- Celtis - gall inductioninduces disc galls on leaves
- Celtis occidentalis - gall inductioncommon hackberry
- Celtis laevigata - gall inductionsugar hackberry
Life Cycle
Females deposit on hackberry leaves at the precise timing of leaf unfolding from buds. Nymphs hatch and feed, inducing the formation of disc-shaped galls in which they develop through five instars. The gall provides shelter and food; nymphs possess wing pads in later instars and exit through a cut made using spike-like projections. Development completes within the gall, with emerging in fall.
Behavior
are capable of jumping to escape disturbance. Fall-emerging adults exhibit strong seeking for shelters, leading to on vertical surfaces of buildings.
Ecological Role
Gall-forming herbivore that stimulates localized plant tissue growth. Serves as for parasitic including Psyllaephagus spp. (Encyrtidae) and Torymus spp. (Torymidae), which develop as within nymphs in galls.
Human Relevance
Considered a nuisance pest when fall-emerging congregate in large numbers on building exteriors, window screens, and door frames. Does not bite, sting, or damage structures; control is typically unnecessary and are transient. Galls do not appear to harm tree health significantly.
Similar Taxa
- Pachypsylla celtidismamaproduces nipple galls on undersides of hackberry leaves rather than disc galls on upper surface
- Pachypsylla celtidisvesiculumproduces blister or vesicular galls, distinct from disc galls
- Pachypsylla celtidisgemmaproduces galls on hackberry buds rather than leaves
- Pachypsylla venustaproduces distinct gall on hackberry
More Details
Gall parasitoids
Multiple of parasitic attack nymphs within galls, including Psyllaephagus pachypsyllae, which has been reared specifically from Pachypsylla galls.
Gall morphology variation
While the disc gall is characteristic, some variation in texture and occasional double galls have been noted, though typically only one nymph occupies each gall.