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Publication #EENY-057

Hackberry Petiole Gall Psyllid,Pachypsylla venusta(Osten-Saken)1

Donald W. Hall, Jerry F. Butler and Harvey L. Cromroy2

Introduction

As its name implies, the hackberry petiole gall psyllid forms woody galls on the leaf petioles of its hackberry (Celtis spp.) hosts. Our native Florida hackberry, Celtis laevigata Willd., is called sugarberry. The petiole gall psyllid is usually not sufficiently abundant to cause serious damage to its host, but gall infested leaves are unsightly during late fall and winter.

Figure 1. 

Petiole gall on sugarberry, Celtis laevigata.


Credits: Jerry F. Butler, University of Florida

Distribution

The petiole gall psyllid is found throughout the range of its four hackberry hosts - from Connecticut to Idaho, southwest to Arizona and southeast throughout Florida.

Description

Adult petiole gall psyllids are fairly large for psyllids (5.0 to 6.0 mm to tip of folded wings) and resemble small cicadas. They are dark colored with tawny markings. The dorsum of the thorax is longitudinally striped. The forewings are whitish with black spots. The full-grown nymph has a green head with brown markings and a green thorax with four light reddish-brown longitudinal stripes. The wing pads of nymphs are brown. The abdomen is green with dark brown transverse bands.

Figure 2. 

Adult hackberry petiole gall psyllid, Pachypsylla venusta (Osten-Sacken).


Credits: Jerry F. Butler, University of Florida

Life Cycle

Last instar nymphs emerge from the galls in spring and molt to the adult stage as new leaves are opening on the host trees. The apex of the abdomen of the last instar nymph is armed with heavily sclerotized teeth which the nymph uses to cut its way out of the woody gall by wagging the tip of the abdomen.

Figure 3. 

Petiole gall psyllid nymph, Pachypsylla venusta (Osten-Sacken), with gall showing individual compartments.


Credits: Jerry F. Butler, University of Florida

Figure 4. 

Last instar petiole gall psyllid nymph, Pachypsylla venusta (Osten-Sacken), showing abdominal cutting teeth.


Credits: Jerry F. Butler, University of Florida

Figure 5. 

Dorsal view of tip of abdomen of petiole gall psyllid, Pachypsylla venusta (Osten-Sacken), showing abdominal cutting teeth -- scanning electron micrograph.


Credits: Harvey L. Cromroy, University of Florida

Figure 6. 

Apical view of abdomen of petiole gall psyllid, Pachypsylla venusta (Osten-Sacken), showing abdominal cutting teeth -- scanning electron micrograph.


Credits: Harvey L. Cromroy, University of Florida

Subspherical galls form around the young nymphs. Galls are polythalamous (having several developing individuals in separate compartments) with each compartment lined with wax. I have found as many as 13 nymphs per gall. Nymphs develop throughout the summer and overwinter as last instars. As in the other species of gall-forming hackberry psyllids, many petiole gall psyllid nymphs are parasitized by Hymenoptera larvae.

Infested leaves die in the fall instead of undergoing abscission and do not fall from the trees. Heavily infested trees are recognizable during the winter by the presence of the dead leaves after uninfested leaves have fallen from the tree.

Because significant damage to the tree does not result from infestation, control of hackberry petiole gall psyllids is not recommended.

Selected References

Johnson, W.T. 1988. Insects That Feed on Trees and Shrubs. 2nd edition. Cornell University Press. Ithaca, New York. p. 452-453.

Tuthill, L.D. 1943. The psyllids of America north of Mexico (Psyllidae: Homoptera). Iowa State College Journal of Science. p.534-535.

Yang, M.-M., and C. Mitter. 1994. Biosystematics of hackberry psyllids (Pachypsylla) and the evolution of gall and lerp formation in psyllids (Homoptera: Psylloidea): a preliminary report. In: P.W. Price, W.J. Mattson, and Y.N. Baranchikov, eds. The Ecology and Evolution of Gall-forming Insects. U.S.D.A. Forest Service (North Central Forest Experiment Station) General Technical Report NC-174. St. Paul, Minnesota. p. 172-185.

Footnotes

1.

This document is EENY-057, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date September 1998. Reviewed March 2011. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Donald W. Hall, Jerry F. Butler, and Harvey L. Cromroy, professors, Entomology and Nematology Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611. Photographs: Jerry F. Butler (Pachypsylla venusta and petiole gall macro-photographs) and Harvey L. Cromroy (scanning electron microscope photographs)

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.