The Oleander Caterpillar
A couple of weeks ago I was visiting a family in a little town in North Florida, where I grew up, called Palatka. My friend Jason explained why he took out all the Oleander bushes in the courtyard of his beautiful new home. He explained that something kept eating his Oleander plants down to nothing. They never looked good, he explained. I asked if he saw these Orange hairy critters always crawling on the brick walls behind the plants. He looked me in the eyes and asked, How did you know? Everyone should know about these critters. His wife Kim loved the Oleander Plants however there is a right plant, right place for all plants. This Courtyard, this entrance to this beautiful home wasn’t the right place for the Oleanders. This orange hairy caterpillar can be very destructive overnight.
They feed, feed, feed until they run out of oleander leaves and then they move on to look for more. Oleander caterpillars are the immature stage of a moth called the Polka Dot moth. The wasp moth gets its name from its appearance which does resemble that of wasps more than moths. It will have blue/green coloration on its wings. The wings and body both have white dots. That is where the term Polka Dots comes in. The young caterpillars hatch from eggs laid by the Adult Wasp moth. The first meal of this caterpillar is its egg shell. Then “Katy bar the door” from there. Oleanders here we come! They always return the next year. It is a never ending battle. The Oleander Plant produces a burst of beautiful flowers and does extremely well in the coastal regions. You can have the large variety or the Dwarf Oleander. Size doesn’t matter to the caterpillars. You will always have the problem of the Orange critters. After its emergence from the egg, the tiny Oleander caterpillar begins feeding on the plant. It is protected from the toxins of the Oleander by its feeding habits. In its first instars this pest feeds on the leaves, avoiding the highly toxic stem and leaf veins. Oleander toxins are highly concentrated in the plant’s vascular system. That is why they say do not burn the plant. The smoke can cause severe breathing problems for humans. Cattle can die if they eat the Oleander. The Oleander Caterpillar knows how to handle the plant. They thrive on it. The smallest will begin to feed on the underside of the leaf. As they grow and transform into larger instars these caterpillars readily consume all the leaves except for the veins, leaving a characteristic skeletonized appearance. As the caterpillar gets larger, it is capable of cutting through the actual leaf stem which cuts off the flow of toxic sap. The feeding habits of different larval stages are what allow the caterpillar to survive feeding on a plant that most pests avoid. The pupa stage is the final one before the adult moth emerges to complete the cycle. The pupae are often found in groups or pupa clusters. That’s part of the reason you avoid installing the plants in your courtyard entrance to the front door. They create a mess on the walls and the eves of your home. They are all over the sidewalks. Try to control the Caterpillars while they are in the beginning stages. Mechanical removal is one method of control. You can spray on a botanical and synthetic pyrethroid.
BT (Bacillus thuringiensis) is a material that kills caterpillars and is often used in vegetable or flower gardens. It only affects caterpillars and will not harm desirable butterflies or Ladybugs as well as other helpful insects. Ask your local retailer for the right product. If you control these Oleander caterpillars while they are young you will save the plant. You have to stay on top of the program.