Farm Forestry New Zealand
PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Recent introduction of Eucalyptolyma maideni Froggatt (Homoptera:Psyllidae) into New Zealand
Scion is the leading provider of forest-related knowledge in New Zealand
Formerly known as the Forest Research Institute, Scion has been a leader in research relating to forest health for over 50 years. The Rotorua-based Crown Research Institute continues to provide science that will protect all forests from damage caused by insect pests, pathogens and weeds. The information presented below arises from these research activities.
From Forest Health News No. 50, February 1996.
On 23 February 1996 foliage was collected from two specimens of Eucalyptus maculata in the Auckland Domain by Chris Scott (MOF Auckland). These trees were heavily infested with lerp making psyllids. The psyllids were identified as Eucalyptolyma maideni. The host plants for this species, in Australia, are Eucalyptus maculata, E. citriodora, and E. gummifera . If this proves to be the full range of hosts in New Zealand then the insect will not be of any economic importance.
In Australia, E. maideni is reported to have three generations per year (trivoltine) and prefers fully mature leaves upon which to feed, oviposit and develop. The eggs are yellow when first laid but darken to a slate grey. They resemble the eggs of the greenhouse whitefly in that they remain erect, are elongate oval and almost parallel sided. Eggs are usually deposited on the lower or basal half of the leaves, they hatch in 10-20 days in spring and summer, but may incubate for months in winter. The nymphs are very mobile and move around much more than other lerp forming psyllids. The lerp is conical with fringed edges, c.10mm in length at final instar.
There are five nymphal stages of development (instars). The first three instars are bright yellow in colour, by the third instar the nymphs become darker, and have a very red colour in the fourth instar. The fifth instar is bright green. Newly emerged adults are bright green but pale to yellow as they age.
Sexual dimorphism is limited to size. Males are smaller and there is an obvious difference in shape of the terminal abdominal segments (genitalia).
All stages occupy existing lerps, and it is not uncommon to find several instars in a mature lerp from the previous generation. The new occupants may add to this existing lerp, these new additions are usually detectable through the dry surface of the old lerp as glabrous, newly produced sections. The nymphs feed with their backs towards the lerp opening.
While feeding the nymphs and adults 'nervously' tap their front tarsi and may move the body around a feeding site in an arc without withdrawing their stylets. This is probably associated with changing the direction of probing within the leaf and selecting the specific cells within which to feed. Adults feed, stridulate and court prior to copulation. Adult feeding apparently stimulates other adults to feed nearby on the same leaves.
Patrick Walsh, NZ FRI
This information is intended for general interest only. It is not intended to be a substitute for specific specialist advice on any matter and should not be relied on for that purpose. Scion will not be liable for any direct, indirect, incidental, special, consequential or exemplary damages, loss of profits, or any other intangible losses that result from using the information provided on this site.
(Scion is the trading name of the New Zealand Forest Research Institute Limited.)
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