Official website of the New Zealand Farm Forestry Association

NZFFA logo: green conifer tree on white background

PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND


Eucalyptus psyllids put their feet up

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 117, April 2002.

The blue gum psyllid, Ctenarytaina eucalypti , fancies the juvenile leaves of its host, Eucalyptus globulus. It can eat and feed just as well on the adult foliage, yet it mates, lays its eggs, and generally prefers to hang about on the waxy juvenile leaves. But the eucalyptus psyllid, Ctenarytaina spatulata , also present in New Zealand, favours the adult
foliage. It mates, lays its eggs, and by and large frequents only the adult leaves. If placed on waxy juvenile foliage,
C. spatulata is unable to feed.

Now a Ph.D. student from University of California Davis, Eric Brennan*, has discovered that the host foliage preferences of Ctenarytaina psyllids apparently depend on the size of their feet! He has found that per unit of body weight, C. eucalypti has a foot (pulvillus) area approximately ten times larger than does C. spatulata. He believes that the slippery epicuticular waxes present on the juvenile foliage prevent the psyllids with smaller feet from gripping the leaf surface. They are unable to maintain their hold, and simply fall off! The psyllids with the larger foot area can cope with the waxy leaf surface, and effectively live their lives with both feet planted firmly on the ground.
 

Toni Withers, Forest Research

* Brennan, E.B.; Weinbaum, S.A. (2001): Aust. J. Entomology 40: 270-277.

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.)

Farm Forestry - Headlines