PEST ALERT:
Glycaspis brimblecombei
Red Gum Lerp Psyllid
Glycaspis brimblecombei (Psyllidae, Hemiptera), commonly referred to as the red gum lerp psyllid, is a sap-sucking insect that feeds on eucalypts. Native to Australia, the red gum
lerp psyllid has been accidentally introduced into the USA, Mexico, Chile, and Brazil, and it has recently been detected in Uruguay.
Females of the red gum lerp psyllid lay between 45 and 700 eggs. The eggs hatch in 10 to 20 days and the nymphs will pierce the plant tissue with their stylet (mouthparts), feeding on the
xylem. As the nymphs feed they secrete honeydew with which they construct a waxy cover (called a lerp) around themselves. This cover is whitish and conical in shape and shelters the insects
until the adult stage. In Australia there are two to four generations per year.
The red gum lerp psyllid is known as an aggressive insect that spreads rapidly. Symptoms of its feeding include dropping of leaves and drying of leading shoots. Infested leaves are covered
with waxy secretions and honeydew, on which sooty mould grows. Heavy infestations can totally defoliate and kill trees. Eucalyptus species differ in their susceptibility to attack
by the red gum lerp psyllid, with E. camaldulensis and E. tereticornis being highly susceptible and E. grandis being more tolerant.
Both chemical and biological control measures have been used in an attempt to control infestations of the red gum lerp psyllid. Contact insecticides are known to be ineffective as the
nymphs are protected by their covers. Systemic insecticides have been used with some success, but their use is of limited value in plantation forestry due to the high cost. In the USA,
natural enemies of the red gum lerp psyllid were imported from Australia. One of these, the parasitic wasp Psyllaephagus bliteus (Hymenoptera, Encyrtidae) has become established in
the USA as a biological control agent for the red gum lerp psyllid.
The red gum lerp psyllid has not yet been detected in South Africa. However, with the increased movement of goods and people between countries across the globe in the last few decades, and
the accompanying accidental increase of invasive species – be it weeds, fungal pathogens, insects, or other organisms – we need to anticipate the arrival of new pest species. New pests in
South America often appear in South Africa soon afterwards (and vice versa). Good examples are the Sirex woodwasp (Sirex noctilio), the eucalypt snout beetle (Gonipterus
scutellatus) and the bronze bug (Thaumastocoris peregrinus). This does not necessarily imply movement from South America to South Africa, but there are patters relating to
time of introduction that are worrying. Thus, the red gum lerp psyllid is a serious Eucalyptus pest that could appear in South Africa in the near future.
The sooner new pests or pathogens are detected, the sooner control measures can be implemented. If you see these symptoms on Eucalyptus, or any unusual symptoms on your trees,
please report it to:
Brett Hurley
Tree Protection Cooperative Programme
Phone: 012 420 3938
Cell: 082 909 3211
Email: brett.hurley@fabi.up.ac.za
The red gum lerp psyllid on a Eucalyptus leaf, showing the white conical lerps of the nymphs (photos by Carlos Rodas, Smurfit Kappa Cartón, Colombia)
