If further testing confirms that it would be safe to introduce the predator, that could come as soon as September, the Maui News reported.

The gall wasp was spotted in Hawaii in 2005. Of uncertain origin, it had been discovered just a year earlier in Taiwan.

Since then, it has been responsible for the death of a large portion of the wiliwili trees in the islands.

Cultivated and introduced species have been the hardest hit, while the native trees have been somewhat protected because they drop their leaves in the summer when the gall wasps are most active.

"Trees in their natural situation aren't getting it as badly," said Mach

Fukada, an entomologist with the Hawaii Department of Agriculture, "but they are getting hit."

Gall wasps lay their eggs in the leaves of the wiliwili and create tumors, or galls, in which the larvae develop into adult wasps that later emerge from the deformed and dying greenery.

With no natural predators in the islands, the wasps have "spread like a wildfire," said University of Hawaii professor Arnold Hara, who is based in Hilo.

The predatory wasp was found in Tanzania by Hawaii Department of Agriculture exploratory entomologist Mohsen Ramadan in early 2006 in tropical east Africa. The predatory insects reproduce by laying their eggs in the galls. The predatory larvae feed on the gall wasp's eggs and pupae developing in the leaf.

Speaking at a seminar at Maui Community College earlier this month, Hara said that the eurytomid wasp "looks very promising."

In the past two years, efforts to control the gall wasp through trimming and chemically treating infested trees have been unsuccessful.

When the coral trees (which are related to wiliwili) on the MCC campus were pruned in the fall of 2005, the foliage that grew back was immediately covered with tumors.

Because the wasps are more attracted to newer foliage than the older, tougher leaves, Hara said, all efforts to trim infected trees have been halted.

In addition, the University of Hawaii has tested a number of chemicals. Imidacloprid was found to be the most successful.

Chemical controls, however, were not consistent and cost more than $300 per tree.

The Department of Agriculture has now turned to biological controls.

Working with representatives from Dar es Salaam University in Tanzania, Ramadan was able to identify three parasitoids responsible for gall wasp population control along the east African coast. The predatory insects were sent to the Insect Quarantine Facility in Honolulu, where they are awaiting approval for release.

"If anything is going to work, it's going to be the biological controls," said Norman Nagata, an assistant extension agent with the UH Cooperative Extension Service.

Before the biological control insect can be released, there are a number of steps that must be taken to ensure that the introduced species will not itself become a nuisance. Since being shipped to Hawaii from Africa, the insects have been kept in a quarantine facility where entomologists monitor their interactions with other native or beneficial species.

"We need to make sure that they will only attack the gall wasp and nothing else," said Neil Reimer, Plant Pest Control Branch chief with the Department of Agriculture.

If the predatory wasps do not attack native plants and insects, then the department can go ahead with the required permit process to allow release.

The department has concluded tests on the predatory eurytomid wasp and is seeking the approval of the Hawaii Board of Agriculture and the U.S. Department of Agriculture's Plant Protection and Quarantine Service.

According to Reimer, the biological control permit process, unlike the haphazard predator releases of the early 1900s responsible for the introduction of the mongoose, requires months of research to ensure that biological agents will consume only what they are meant to.

"Things are done very carefully," he said. "It's been actually very safe."

According to Hara, more than 650 biological controls have safely been released in Hawaii over the past few decades.

If the predatory wasp is approved, it may be ready for release by September, he said.

However, there is no guarantee that the predator will thrive as well in Hawaii as the gall wasp has.

Rather than fighting infestations as they arise, state agriculture officials are reaching out to the public to keep an eye out for invasive pests, They urge everyone to learn more about threats to Hawaii's ecosystem.

"Invasive species will continue to be a major crisis here," Hara said. "Residents should be aware of unusual pests . . . that helps early detection and that's critical."