Psyllidae

jumping plant lice, psyllids

Subfamily Guides

9

, commonly known as jumping plant lice or psyllids, is a of small plant-feeding insects within the true bugs (Hemiptera). Members are typically very -specific, with most restricted to feeding on a single plant (monophagy) or closely related plants (oligophagy). The family is part of the Sternorrhyncha, a group considered the most basal lineage within Hemiptera. Psyllids are characterized by their jumping ability using modified hind legs, and many species produce protective waxy secretions or . Several species are economically significant as pests of fruit trees and ornamental plants, while others have been employed as agents against plants.

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Pronunciation

How to pronounce Psyllidae: /sɪˈlɪdiː/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Psyllids may be distinguished from similar small Hemiptera by their jumping hind legs, long , and wing posture. They differ from aphids (Aphididae) by more robust body form, jumping ability, and absence of cornicles (siphuncles). Barklice (Psocodea) resemble psyllids superficially but possess chewing rather than . nymphs within galls or under can be identified by the characteristic structure of these coverings; gall shape, size, and location on the plant often indicate the responsible.

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Habitat

Primarily associated with woody plants including trees and shrubs. Found in orchards, hedgerows, forests, and urban plantings where occur. Many species inhabit specific microhabitats on host plants: leaf surfaces, buds, shoots, or within galls. Some species seek sheltered sites away from host plants, including building exteriors and crevices.

Distribution

Worldwide distribution with greatest diversity in tropical and subtropical regions. Well-documented from North America (including California and Florida), Europe (Scotland, extensive records), Southeast Asia (Philippines, Borneo/Malaysia), Australia, and South America (Venezuela). Many have restricted ranges tied to plant distribution; some have expanded ranges through human-mediated transport of host plants.

Seasonality

Most temperate are with present from late spring through autumn. Hackberry psyllids (Pachypsylla spp.) emerge as adults in late summer and seek sites, becoming conspicuous nuisance pests on building exteriors in early fall. Some species exhibit summer dimorphism: early-emerging adults are brachypterous (short-winged), later adults (long-winged). stage typically overwinters, though some species overwinter as adults.

Diet

Phloem sap feeding; both nymphs and feed on the same plant using . Strong host specificity is characteristic: most species are monophagous (restricted to single host ) or oligophagous (few related hosts). Documented host associations include Eucalyptus, hackberry (Celtis), apple (Malus), pear (Pyrus), hawthorn (Crataegus), alder (Alnus), poplar (Populus), willow (Salix), and Melaleuca.

Host Associations

  • Eucalyptus - Multiple including Cardiaspina, Glycaspis, Boreioglycaspis; some produce , others cause gall-like damage
  • Celtis (hackberry) - Pachypsylla spp. induce nipple galls on leaves
  • Malus (apple) - Psylla mali; historically introduced to orchards
  • Pyrus (pear) - Cacopsylla pyri, C. chinensis; major orchard pests
  • Melaleuca quinquenervia - Boreioglycaspis melaleucae introduced as biocontrol agent in Florida
  • Shepherdia (buffaloberry) - Bactericera arbolensis and potentially undescribed related

Life Cycle

Typically (one per year). Females deposit singly or in small groups on plant buds, shoots, or leaf margins in late summer or autumn. Eggs overwinter, hatching when host leaves unfold in spring. Nymphs pass through five instars over 4-6 weeks, feeding and developing within protective galls or under . emerge by early summer, mate, and disperse to oviposition sites. Some form galls through plant tissue manipulation; others secrete waxy lerps for protection.

Behavior

Strong jumping ability using enlarged hind to escape . of some exhibit aggregating when seeking shelter, becoming nuisance pests on buildings. via substrate vibrations has been documented in at least Cacopsylla pyri. Nymphs are comparatively sedentary, remaining attached to feeding sites within galls or under . Some species show seasonal wing dimorphism.

Ecological Role

Herbivores on woody plants; form component of plant-based . Serve as prey for various including lady beetles (Coccinellidae), predatory such as Clitemnestra bipunctata, and parasitic wasps (Encyrtidae, Torymidae). Some act as of plant : pear psyllids transmit phytoplasmas causing . Several species have been employed as agents against plants, notably Boreioglycaspis melaleucae against melaleuca in Florida.

Human Relevance

Several are significant agricultural and horticultural pests, particularly of fruit trees (apple, pear) and ornamental eucalyptus. The Redgum (Glycaspis brimblecombei) is a serious pest of eucalyptus in California. Hackberry psyllids become nuisance pests when aggregate on buildings seeking sites. Conversely, some species provide beneficial biocontrol of plants. Historically, some psyllid lerps were consumed by peoples as food sources.

Similar Taxa

More Details

Taxonomic history

Psyllids were traditionally treated as a single , but modern research has recognized multiple families within Psylloidea. The family Psyllidae in the strict sense now excludes groups such as Triozidae and Aphalaridae.

Lerp structure

produced by many are crystalline secretions formed from excess sugar in phloem sap. These structures vary remarkably in form—flat, conical, filamentous, or shell-like—often serving as species-diagnostic characters.

Conservation considerations

Some are extremely rare and potentially threatened, particularly those restricted to specific plants with limited distributions. However, most research focuses on economically significant pest species.

Sources and further reading