When the Christmas trees arrive in Hawaii, they are shaken to get the invasive species out.
This year, the state Department of Agriculture says about 10 percent of the first shipment of trees have invasive species.
Here's a closer look at one of the slugs from the trees.
Oregon Christmas Tree Yard
HDOA inspector Todd Kikuchi (left) and ODA inspector Gary Romehill check for insect pests after trees are shaken in Oregon to dislodge pests before loading in shipping containers.
Click here to read more about the first shipment of Christmas trees to Hawaii in 2013.