HONOLULU -- Wiliwili trees have been reduced to piles of sticks all over the state -- the result of larvae laid by microscopic wasps -- leaving property owners to question what to do about the trees.

It has been a year since Erythia gall wasps started attacking wiliwili trees across the state. The larvae of the wasp hatches on the tree, causing plant cells to grow abnormally, deforming the leafs on the trees and ultimately killing them.

Neil Reimer, of the Department of Agriculture, said leafless trees will eventually die, but if there are still signs the tree is alive, it might be salvageable.

"If you go in and irrigate them and allow the green to come up, get a good fertilizer program going, the trees will start to recover," Reimer said.

Because the gall wasp will attack again, a systemic insecticide is recommended for surviving trees.

"There are some systemics available for killing insects on trees. One that has worked fairly well for us is called Merit," Reimer said.

Merit is used as a drench and is poured around the base of the trees so the root system can pick it up.

Meanwhile, the Department of Agriculture continues to experiment with natural predators to the gall wasp.

"We've got in quarantine right now three different species of parasytoids that attack the gall wasp, and we are running through studies to make sure they are host-specific. We don't want to release something that is going to attack something else," Reimer said.

The process could take a couple of years, Reimer said.