What causes the stem of a plumeria to be eaten away?
The Gardener’s Answer
Hello, Marv: Plumeria is a tropical for those of us gardening in Kentucky but a perennial in your hardiness zone. It belongs to the same family as oleander and pachypodiums, all of which possess low levels of toxicity if ingested. That being said, most animals, especially wild ones, steer clear of toxic plants. Is the entire plant being chewed on or just a single stem? These tropicals are known for having a few pest problems, especially if they are not planted in an ideal location. Plants that are stressed are more susceptible to insect and disease problems. The longhorn borer is a grub of the longhorn beetle and lives inside the stem and eats the plant from the inside. You would notice black ooze on the stem if this were the culprit. Another possibility is the cutworm, which would be more common at the base of the plant. One last possibility is a slug or snail; with either one of these you would notice slime on the stem. For a positive diagnosis you can take a sample to your County Cooperative Extension Service. Your horticulture agent will be able to give you a definitive answer and suggestions in terms of control.