Hackberry Nipplegall Maker

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Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Superorder	Paraneoptera
Order	Hemiptera
Suborder	Sternorrhyncha
Superfamily	Psylloidea
Family	Aphalaridae
Subfamily	Spondyliaspidinae
Genus	Pachypsylla

Scientific Name

Pachypsylla celtidismamma

Common Name

hackberry nipplegall maker

Compiled by Whitney Cranshaw, Colorado State University:

Pachypsylla celtidismamma (Riley)
Homoptera: Psyllidae

Hosts

Hackberries

Sugarberry (Celtis laevigata )

American or Commom hackberry (Celtis occidentalis )

Net-leaf hackberry (Celtis reticulata )

Damage and Diagnosis

Galls formed by Hackberry nipplegall maker.

Hackberry nipplegall psyllid produces prominent warty leaf galls, sometimes nearly covering the leaf. High levels of galling are usually restricted to only a few branches and do not produce much damage. However, the galls are sometimes considered to be unattractive. The pale-yellow nymphs can be found within the galls until they emerge in early Fall.

Life History and Habits

Hackberry nipplegall psyllids overwinter as adults in protected areas. In spring as the hackberry buds are expanding, the adults emerge and deposit eggs on the undersurfaces of the leaves. Eggs hatch and young nymphs begin to feed on the leaf. An overgrowth that appears as a raised swelling on the lower leaf surface is induced by this feeding, ultimately producing the gall that covers the insect. The nymphs develop within the gall all summer and adults emerge in late summer. There is one generation per year.

There can a great difference in the number of galls produced on different leaves within the tree or between nearby trees. This is largely due to how synchronized the leaf development is when the adult psyllids are laying eggs and eggs are hatching since leaves are suitable hosts for only a brief period during their early development.

Related Species

The hackberry blistergall psyllid, Pachypsylla celtidisvescula Riley, produces a gall in the form of a small raised swelling, often concentrated around the base of the nipple galls on the upper leaf surface. Life cycle of this species is similar to the hackberry nipplegall maker. Blistergall psyllids are small enough to pass through most screens and sometimes enter nearby homes during fall and can be a nuisance problem in homes.

Another gall-maker, Pachypsylla venusta Osten Sacken, sometimes forms large galls on the petioles of net-leaf hackberry.

Management

The hackberry nipplegall psyllid is commonly attacked by parasitic wasps that help reduce populations. The wasps remain in the old galls through the winter, emerging the following spring.

Hackberry psyllids are also common and important prey of many resident and migratory birds. Overwintering psyllids are favorite prey of chickadess, creepers, nuthatches, and other species. Migrating warblers, ruby-crowned kinglets, pine siskins, American goldfinches and chipping sparrows eat many adults in spring. Psyllids within galls are sometimes extracted by house finches, evening grosbeaks and fox squirrels.

Controls are rarely needed to protect tree health and most applications are made for aesthetic reasons. Insecticides should be applied to coincide with periods when eggs are being laid and systemic activity is useful for optimizing control. The eggs can be easily seen on the underside of newly expanding leaves.

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.