Psyllids and lerps

Psyllids (also known as jumping plant lice or lerp insects) are sap-sucking insects related to aphids. The adults are highly mobile.

Lerps are protective covers made by the nymphs (larval stage psyllids that resembles adults) to help protect them from natural enemies and dehydration. They are formed when nymphs excrete honeydew on the leaf surface – the sugars and amino acids in the honeydew crystallise in the air to form lerps. Lerp size and shape varies between species of psyllid. Leaves can look black and sooty when moulds grow on the honeydew.

Both adult and nymph psyllids are sap suckers, feeding on phloem sap through straw-like mouthparts. They have little effect on trees when population levels are low; however, heavy infestations of nymphs can cause significant leaf-drop, defoliating trees.

Scientific name

Glycaspis species, Cardiaspina species, Creiis lituratus, Eucalyptolyma maideni

Similar species

  • Free-living psyllids, such as the blue gum psyllid (Ctenarytaina eucalypti) and Blastopsylla species, are similar insects, but they do not produce lerps. They produce honeydew, white woolly filaments and powdery material resembling cotton wool on leaves. These species are found throughout Australia, usually in cool climates, and do not usually cause severe damage unless in high numbers.


Glycaspis psyllids or sugar lerps (Glycaspis species)

  • Adults are around 4mm long from head to wing tips.
  • Nymphs resemble wingless aphids; they enlarge the lerps or construct new ones as they grow.
  • Lerps are:
    • squarish to conical
    • up to 5mm in diameter
    • usually white but sometimes yellowish or grey
    • often found on the upper surface of leaves along the midrib
  • Sooty mould growth is often present.
  • See additional images.

Cardiaspina psyllids or basket lerps (Cardiaspina fiscella and C. maniformis)

  • Adults are up to 8mm long and winged.
  • C. fiscella lerps are lacy and basket or shell-like, yellow-brown, mostly on lower leaf surfaces and mostly on mature foliage. Psyllid nymphs can be seen under the lerps if present.
  • C. maniformis lerps are ribbed, scalloped, light yellow, mostly on upper leaf surfaces and mostly on mature foliage.
  • Both lerps are 1–4mm long.
  • See additional images.

Creiis psyllid (Creiis lituratus)

  • Adults are orange, red or brown with mottled wings; they are strong flyers.
  • Lerps are round or shell-like, 1–5mm long, smooth, opaque or semi-transparent.
  • Lerps are found on both sides of leaves, but predominantly on the underside, and more commonly on older leaves.
  • Nymphs can be seen under lerps if present.
  • See additional images.

Spotted gum psyllid (Eucalyptolyma maideni)

  • Adults are initially bright green, turning pale to yellow with age.
  • Nymphs are bright yellow, reddish and then bright green as development progresses.
  • Nymphs are usually mobile and are often seen outside the lerp.
  • Lerps are white, flat and fern or feather-shaped.
  • Lerps are typically 10mm long and 3–4mm wide.
  • They are more common on the underside of leaves and on mature leaves.
  • See additional images.


  • Glycaspis psyllids – northern and south-eastern Queensland.
  • Cardiaspina psyllids – throughout Queensland and Australia.
  • Creiis psyllids – occur throughout coastal New South Wales to the Queensland border.
  • Spotted gum psyllids – throughout Queensland where spotted gums are present.


Glycaspis species

  • Rose gum and hybrids (Eucalyptus grandis)
  • Gympie messmate (E. cloeziana)
  • Blackbutt (E. pilularis)
  • Red stringybark (E. resinifera)
  • Swamp mahogany (E. robusta)
  • Sydney blue gum (E. saligna)
  • Red ironbark (E. sideroxylon)
  • Forest red gum (E. tereticornis)

Cardiaspina species

  • Rose gum and hybrids (Eucalyptus grandis)
  • Swamp mahogany (E. robusta)
  • Sydney blue gum (E. saligna)
  • Forest red gum (E. tereticornis)

Creiis psyllid (Creiis lituratus)

  • Dunn's white gum (E.dunnii)
  • Grey gum (E.propinqua)

Spotted gum psyllid (Eucalyptolyma maideni)

  • Spotted gum (Corymbia citriodora subspecies citriodora, C. citriodora subspecies variegata, C. maculata)
  • Red bloodwood (C. gummifera)


  • Glycaspis species do not usually cause direct damage to leaves, but they produce honeydew, which promotes the growth of sooty mould. However, large numbers can cause defoliation.
  • Cardiaspina species cause the localised death of leaf cells around feeding sites, which initially turn red-purple and later brown. At high densities, the whole leaf becomes diseased and sheds.
  • Creiis lituratus feeding produces reddish-purple leaf tissue that becomes diseased and brown, and often dies. High densities of lerps discolour the crown and can cause defoliation, tip dieback and sometimes tree death. This is an important pest of eucalypt plantations, especially E. dunnii plantations in New South Wales.
  • Eucalyptolyma maideni is common on spotted gum but does not usually cause defoliation. High densities may encourage sooty mould growth.


Psyllids are naturally predated upon by a range of small birds and other insects. The eggs and nymphs are also parasitised by a range of wasp species.

Temperature and relative humidity affect the abundance of Glycaspis species. Low temperatures and high humidity were correlated with low psyllid numbers.

Resources and research