Invasive guava might meet its match

HILO » After 183 years of strawberry guava degrading Hawaii's native forests, federal scientists think they have finally found a bug that will slow down the destruction.

The candidate for release by the U.S. Forest Service this summer is a Brazilian scale, a type of insect related to aphids.

The bug will be released in the Olaa Forest Reserve along the upper reaches of the Stainback Highway south of Hilo.

If the release goes as planned, the little bug, formally known as Tectococcus ovatus, will form galls, or bumps, on the leaves of strawberry guava, also known as waiawi, weakening the plant and slowing its fruit production.

"The insect does not kill the plant outright," a statement from the Forest Service said.

In fact, the Forest Service names some other invasive plants that have been subject to biocontrol in the past: prickly pear cactus, lantana, banana poka and ivy gourd.

Despite some control, those plants are still commonly found in Hawaii.

American scientists have been studying Tectococcus since 1993 in Brazil and for the past six years in Hawaii. The bug attacks only strawberry guava, not the closely related common yellow guava.

The plant has its human supporters because of its undeniably delicious fruit.

The Forest Service notes that wild pigs like the fruit for the same reason, and they spread the seeds in their droppings, adding to the threat to native forests.

That plant is also a threat to native culture, since cultural practitioners go into forests to pick native plants, but those plants have been crowded out by strawberry guava.

A public comment period on a draft environmental assessment regarding release of Tectococcus ends today. People may call Tracy Johnson, U.S. Forest Service researcher on the Big Island, at 967-7122 or e-mail comments to tracyjohnson@fs.fed.us.