New invasive pest sweeping across Guam, feeding on local plum trees

A new invasive pest has reached our shores and they’re taking a bite out of a local fruit tree. The Guam state entomologist warns the community to keep an eye out for these tiny but voracious beetles.

At about the size of a thumbnail, these tiny pink beetles resembling lady bugs may look cute, but they’re a serious invasive pest state entomologist Christopher Rosario is warning the community about.  "The people who have been reporting the beetle have been noticing that their tree has been completely defoliated. So these beetles, both the adults and the larvae, are feeding on the leaves," he shared.

A concerned resident first reported the strange new beetle back in March. It wasn’t until June that experts were able to identify the voracious eaters. "It was identified by entomologist Ken Puliafico and then it was confirmed by myself. This pest is known as the hog plum beetle," Rosario added.

And as the name hints at, these hog plum beetles feed on plum trees. On Guam, that’s the Spanish Plum Tree, locally known as siniguelas. "Siniguelas are actually pretty good. It’s sweet tasting. I don’t know what kind of mix it has but it tastes really good actually. Just knowing I had my first siniguela for the first time and now this beetle is here, it’s kind of a bummer," Rosario said.

These abundant plum trees that can be found growing in backyards are now at risk of dying.  The hog plum beetles are already sweeping across the island, with already eight sightings reported in five different villages. 

Rosario says it’s past the point of eradication. The focus now is getting them under control, as he added, "Right now, I can’t make any recommendations as to what kinds of insecticides you would want to use to prevent the beetle from feeding on your tree. But a little bit more research, more collections, and we’re going to have to do test trials to learn how to control the beetle. But right now we’d really ask the public to report them so we can see how widespread the beetle is."

He says with the community’s help, the biosecurity team at the Department of Agriculture will be able to then request for federal funding. 

If you see this beetle, you’re asked to call the pest hotline at 671-475-PEST (7378).