Saving Eucalyptus Trees Worldwide

Combating Damage to Forests by Wasps

The peak of unique projects with enormous financial ramifications - especially for developing countries – is connected to, of all things, a tiny insect discovered by Israeli scientists working in distant Australia - thanks to generous funding from the Australian Friends of KKL-JNF. The objective of the project was to identify the creature that could put an end to the plague of gall wasps in Australia - insects that endanger millions of acres of eucalyptus tree plantations intended for industry and for energy production throughout South-East Asia, the USA, Africa and South America.

The natural enemy of the gall wasp is a tiny insect less than 2 millimeters long. It was identified in Australia by Dr. Zvi Mendel from Israel’s Volcani Institute of Agriculture and David Brand of KKL-JNF, who trapped and brought it to Israel. Like the gall wasp itself, this insect is also a wasp, a parasite, whose absence in nature outside Israel led to the unchecked development of eucalyptus gall wasps. By propagating the parasites in captivity at the Volcani Institute, new generations of the gall wasp’s natural enemy have been produced. Wherever these tiny insects have been released in eucalyptus groves infested by gall wasps, they start operating immediately, and have a significant effect within a few months.
Photo: KKL-JNF Photo Archive
Photo: KKL-JNF Photo Archive
In South Africa, millions of acres of eucalyptus forests have been saved since May 2009 from the damage caused by gall wasps that penetrated this area only recently and became a serious threat to its commercial forests. KKL-JNF representatives took part in the annual forestry conference held in Pretoria where they helped researchers from the Forestry and Agricultural Biotechnology Institute (FABI) to release parasite wasps into the FABI’s securely closed quarantine facility of the University of Pretoria, also providing them with practical guidance on providing the optimal habitat for the natural predators of gall wasps.

The audience was extremely impressed by KKL-JNF’s knowledge and as a result of the conference an extensive foundation for forestry cooperation has been laid between KKL-JNF and South Africa.

The strange story of the wasps that attack eucalyptus trees and the other wasps that help control these pests illustrates the international nature of modern ecological problems and solutions alike.
There are a number of species of tiny wasps in Australia that lay their eggs in the soft tips of eucalyptus branches or on the young leaves. The larvae create growths or “galls” on the trees that cause the deterioration of the leaves and branches, inhibiting the development of eucalyptus saplings and eventually killing the trees.

Natural enemies of the eucalyptus gall wasps also thrive in Australia. These are another variety of parasitic wasps that utilize the larvae of the gall wasps as food for their larvae. Consequently, in Australia, where the eucalyptus tree originated, there is a natural balance between the pest and its natural enemies, and damage by gall wasps for the most part remains negligible.

In recent years, however, the parasite wasps have made their way to many other parts of the world. Two species of the wasp invaded other countries in the Mediterranean Basin, as well as India, Thailand and Africa. KKL-JNF researchers succeeding in locating and identifying natural enemies (other wasps) of these wasps. As part of our international cooperation we have exported these natural enemies to Turkey, Portugal and Greece and assisted these countries in fighting the harmful pest. We have received further requests to export them to India, Thailand and South Africa, where there are extensive eucalyptus plantations.
Photo: KKL-JNF Photo ArchiveThe first international conference on control of the eucalyptus gall wasp, organized by KKL-JNF and the Volcani Institute for Agricultural Research, took place in Israel in November 2008. The conference attracted scientists and wood industry executives from China, Thailand, India, Turkey, Italy, Kenya, Uganda, Brazil and the USA. The aim of the workshop was to provide the participants with information on operating biological pest control of the Australian gall wasp. At the end of the workshop each visitor received a unique present: A small cardboard box containing hundreds of the Israeli-grown wasp parasites that are the natural enemy of the Australian gall wasp. About a year later, the international workshop participants began reporting to KKL-JNF about the enormous success of the wasp parasites: Extermination of gall wasps in eucalyptus forests. The significance of this success is the rescue of entire branches of global economy with long-term importance for many participating countries, both in terms of raw materials for the wood industry and also of fuel for rural populations who lack any other source of energy.

After an intensive week of study and field observations, Professor Mendel instructed participants who came from twelve different countries on how to propagate and release two species of parasitic wasps that eradicate the gall wasps during their larval and pupa stages and prevent them from multiplying beyond control.

The participants also toured KKL-JNF forests in the southern Hebron Mountains and learned more about the project to eradicate the gall wasp, funded by JNF Victoria, Australia, as well as other aspects of forestry work in this semi-arid region.