Quick Dips

Welcoming an Uninvited Guest

Another uninvited insect has arrived in New Zealand, but the 2mm-long psyllid, or jumping plant louse, could be a welcome addition to the country's useful insect fauna. The louse, found so far only in the Auckland area, feeds on Acmena smithii (also known as Acmena, monkey apple and lilly-pilly) which is a threat to forest and shrublands and has been designated as a National Surveillance Plant Pest.

"We don't yet know how much damage this new psyllid can, or will, do to Acmena, but if it proves able to reduce vigour, or reduce flowering or fruit set, it will be a useful tool in reducing the spread of this plant," says HortResearch entomologist John Charles.

Earlier this year the new insect was found attacking Acmena in the Mt Albert area of Auckland. It has tentatively been identified as Ctenarytaina sp.

"We don't know how this insect arrived here or, at this stage, where it came from," Charles says.

These insects produce copious quantities of honeydew (a sugary sap from the plant that is excess to the insect's food requirements) in white or opaque-looking droplets which fall onto the leaves below. Charles says it is the sight of these white balls on the leaves which may first indicate the presence of the insect.