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Lerps and psyllids
- Lerps of Eucalyptolyma maideni on spotted gum.
General information
Lerps are the protective covers made by nymphs of jumping plant lice or psyllids (Homoptera/Hemiptera, Family Psyllidae). Nymphs excrete honeydew on the leaf surface and the sugars and amino acids in the honeydew crystallise in the air to form lerps. Leaves can look black and sooty when sooty moulds grow on the honeydew. Lerp size and shape varies between species of psyllid.
Adult and nymph psyllids are both sap suckers and heavy infestations of nymphs can cause significant leaf-drop and defoliation in trees.
Creiis psyllid (Creiis lituratus) is an important pest of eucalypt plantations throughout coastal New South Wales to the Queensland border.
| Scientific name |
Glycaspis species and Cardiaspina species |
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Description |
- Glycaspis species (sugar lerps): lerps are squarish to conical, up to 5 mm diameter, usually white and sometimes yellowish. The secreted honeydew promotes sooty mould growth.
- Cardiaspina species (basket lerps): lerps 1-4 mm lacey and basket-like, mostly on lower leaf surfaces (C. fiscella) or ribbed, scalloped, yellow mostly on upper leaf surfaces (C. maniformis). Foliage can appear purple or brown.
- Creiis psyllids construct round, semi-transparent lerps which shelter the feeding nymphs.
- Eucalyptolyma maideni (spotted gum psyllid): lerps are white, flat and fern-shaped.
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| Distribution |
- Cardiaspina and Glycaspis psyllids occur in southeastern and northern Queensland
- Creiss psyllids occur in throughout coastal New South Wales.
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| Hosts |
- rose gum and hybrids
- Gympie messmate
- blackbutt
- spotted gum.
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| Damage |
- Glycaspis species do not cause direct damage to leaves, but produce honeydew, which promotes the growth of sooty mould.
- Cardiaspina species can cause severe defoliation due to necrotic lesions forming around feeding sites. At high densities, the whole leaf becomes necrotic and is shed.
- Creiis feeding produces reddish-purple leaf tissue that becomes necrotic and brown, and often dies. High densities of lerps cause discoloration throughout the crown.
- Eucalyptolyma maideni is common on spotted gum although it doesn't cause defoliation. High densities may encourage sooty mould growth over leaves.
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Resources
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