Psyllids

Definition

Small, sap-sucking insects in the superfamily Psylloidea (order Hemiptera), commonly called jumping plant lice. Psyllids are highly host-specific, with most species feeding on a single plant species (monophagous) or a few closely related plants (oligophagous). Adults possess enlarged hind femora enabling a characteristic jumping escape response, and nymphs often produce waxy secretions or inhabit enclosed galls. Together with aphids, phylloxerans, scale insects, and whiteflies, they comprise the suborder Sternorrhyncha, traditionally regarded as the sister group to other Hemiptera. Recent classifications divide Psylloidea into seven families, with Psyllidae sensu stricto containing over 70 genera.

Etymology

From Greek psyllos (flea), alluding to their jumping habit and small size.

Example

The Asian citrus psyllid (Diaphorina citri) vectors Candidatus Liberibacter bacteria, the causative agents of citrus greening disease (huanglongbing), making it one of the most economically significant psyllid pests worldwide.

Synonyms

• Jumping plant lice
• Plant lice

Related Terms

• Sternorrhyncha
• aphids
• whiteflies
• Scale insects
• Phylloxera
• Hemiptera
• Host specificity
• Gall insects
• Vector (disease)

Usage Notes

The term 'psyllids' historically referred to a single family Psyllidae, but current taxonomy recognizes seven families within Psylloidea (Psyllidae, Triozidae, Aphalaridae, Carsidaridae, Homotomidae, Calophyidae, and Phacopteronidae). 'Psyllid' remains the vernacular for all members of the superfamily. Contrast with aphids: psyllids have more host fidelity, more pronounced jumping ability, and typically more complex wing venation. Some species induce distinctive plant galls; others are free-living on foliage or stems.