Some of Sacramento's most iconic trees may soon be at risk and the culprit is a tiny beetle capable of killing valley and blue oak trees.

The pests, called Mediterranean oak borers, were first detected in Napa and Sonoma counties, and experts say it was only a matter of time before they reached Sacramento.

The first infected tree in the region was discovered last year on a golf course near Citrus Heights. Since then, the beetles have also been spotted in a residential park and along the river. They burrow into older oaks to lay their larvae, but the greater danger comes from a deadly fungus they carry, which weakens the tree. The disease can spread to other oaks when infested wood is moved.

Trees hundreds of years old are especially vulnerable, according to urban foresters.

"It primarily goes after the oldest trees because they might be under the most stress," said Kevin Hocker, the City of Sacramento's urban forester. "So we're not just losing a couple trees, we're losing the biggest and the best, and left unchecked, we could lose quite a number of them."

Experts urge residents to keep oak trees healthy with regular watering and fertilizer, avoid transporting oak firewood, and chip or compost any infected wood.

With no cure and limited funding, crews are relying on the public and prevention to help stop the beetle from spreading and destroying what's left of Sacramento's iconic oak canopy.