A tiny wasp that has ravaged eucalyptus groves in the Mediterranean Basin, Africa and the Far East, and which arrived in Israel a few years ago, has proven anew that no organism is eternally dominant. Israeli researchers have found a predator one millimeter in length called Closterocerus, which thwarts the wasp's advance.

Several nations have already turned to Israel for information about this natural adversary. David Brand, head of the Jewish National Fund's (JNF) Department of Forestry and Development, says, "Six years ago, two species of wasps were discovered to create galls [abnormal swellings of plant tissue], thus damaging eucalyptus leaves: the Leptocybe invasa, which damages new leaves, and the Ophelimus maskelli, which damages mature leaves. Both wasps subject eucalyptus trees to continuous attack."

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The wasps reproduce on eucalyptus leaves, blanketing them and causing the leaves to fall. The wasps spread "like wildfire," according to David Brand, halting the trees' growth.

In Israel, the wasps are prevalent from the Southern Golan Heights in the North to the Western Negev Desert in the South. They also attack eucalyptus groves in Italy, Greece, Portugal, Kenya and South Africa, and there are reports of damage to trees in Vietnam, India and Thailand.

Massive damage to eucalyptus trees compelled a team of JNF-funded scientists to launch research three years ago to identify the pest's biological adversaries. Professor Zvi Mendel of the Agriculture Ministry's Agricultural Research Organization (ARO), Dr. Alex Protasov, Dr. Zion Madar, Nitza Sapir and David Brand traveled to Australia to find the wasp's natural enemy. There, they were assisted by Dr. John La Salle and Joe Krycer, a member of JNF-Australia. "It was like finding a needle in a haystack," Brand says, "because there are dozens of pests and dozens of predators."

After they found leaf tissue scarred by galls like those that developed in Israel, they took samples and sent them to Israel. Here, researchers followed the development of wasp larvae that emerged from the galls and the development of the wasp's predator, which hatched from the leaves at the same time. The scientists closely observed the Closterocerus to ensure that they only preyed on the wasps' eggs and larvae and did not damage other insects.

After a year of testing the predator's behavior, researchers received approval from the Agriculture Ministry Plant Protection and Inspection Services to release the Closterocerus into Israel's forests. This approval only applies to Ophelimus maskelli wasps, as it is still unclear that Closterocerus can control Leptocybe invasa wasps without damaging other species.

"There has been palpable reduction of the damage done by Ophelimus maskelli," says Brand. "According to reports, its predator naturally migrated to Jordan, Egypt, and Turkey."

Nations located farther from Israel requested that the Israeli research team send the predator to them. South Africa, a nation with commercial eucalyptus groves that feed its wood and paper industries, recently turned to Israel for assistance. Professor Mendel also received requests for help from India and Thailand.

"In India and Thailand, eucalyptus groves are gravely threatened by the wasp," says Brand. "This represents tremendous financial damage. In commercial forestry, damage in cents per dunam determines the size of income."

Israeli experts in this field recently traveled to Thailand and will soon leave for South Africa.