Oleander caterpillars hatch from eggs that have been laid under plant leaves. The caterpillars got their name because they prefer to feed on Oleander leaves, but don’t let the name fool you: they can and will eat other plant material, like the Desert Rose or Mandeville Vine. We found an army of Oleander caterpillars on our property attacking our Mandeville vines. Looking back, we should have recognized the signs before seeing the caterpillar itself.
Signs that the Oleander caterpillars are feeding on your plants:
- Black droppings on the ground around a plant
- Webs within the plant itself with black droppings in it
- Black dropping s piled on top of individual leaves
- Plant material looking weak and/or bare
If you recognize any of these signs or see an actual caterpillar, you will want to get rid of the pests as soon as possible. Oleander caterpillars can defoliate a plant within days. Usually the plant will not die but not tending to this nuisance will create an infestation that can be hard to control.
Plant material that has had Oleander caterpillars feeding on it can over time become weak which opens the door for other insects, stresses and diseases.
Cutting off the plant material along with the caterpillars and disposing of them in a trash bag can lessen the caterpillar population. Use gloves when handling oleanders, as these plants contain a poisonous sap and the caterpillars themselves can cause an itchy rash. Calling your landscape professional to treat the plant material is important. They will treat the caterpillars that you do not see and the eggs that have been laid under the leaves of the plant.