“I have the ugliest caterpillar living on my orange trees, eating the leaves. There are more than one. They are dark in color, with different markings. These are just smaller than your little finger, with the top or face part ????, bigger than the tail. What are these, and should I get them off my Orange Trees. Tree’s are only about five years old, so they are small in size. Question from Colleen of Englewood, Florida
Answer: There are several caterpillars that could be eating your oranges, but the ugliest is that of the giant swallowtail butterfly (Heraclides cresphontes), which is common in your state. It is also called the orange dog caterpillar. The caterpillars are large (up to 4 inches), with a large head of dark brown and ivory or yellowish markings (particularly at the tail). The butterflies then turn into fantastically beautiful and important pollinators. They are the largest swallowtails in North America, but boy are their young unsightly. Thankfully, they are never in numbers to do real damage to orange trees unless the trees are tiny, so I would leave them alone if you can. The beauty and value of these butterflies outweighs the loss of a few leaves.
There are a few other orange-tree-eating caterpillar possibilities, which are not as ugly, and don’t fit your description. The oleander caterpillar is one. It appears in larger numbers and is orange with conspicuous long, black tufts of hair from head to tail, but I am almost positive that you have giant swallowtail caterpillars.
If so, you may want to watch them until they form chrysalises and burst forth into the huge butterflies they become. I hope that this information helps!
Black Gold Horticulturist