Bill said he pulled these orangedogs off of his key lime tree. View the photo on Instagram here.
What kind of bugs are they, and are they harmful to plants or humans?
Lyle Buss, University of Florida entomologist, said that these bugs in the photo are orangedogs, caterpillars of the giant swallowtail butterfly. These critters use several defense mechanisms to fend off predators. For example, the young larvae avoid predation by resembling bird feces.
Buss explained that like most members of the swallowtail family, orangedogs have a forked structure called an osmeterium behind their head that stick out when they are disturbed. It scares predators off and releases a foul smell. While orangedogs are not harmful to humans, they are commonly found on citrus, eating much of the new foliage.
To control their population on small trees, Buss suggested hand picking off the larvae. Another option is insecticides that are registered for use against caterpillars (listed in this publication). According to Buss, Bacillus thuringiensis (Bt) is a good choice because it does not harm beneficial insects that help control orangedogs and other pests. Of course, always read the label before applying any insecticide.
If you would like your bug identified and additional information, a great place to start is your local County Extension Office. With an office located in every county, it has never been easier to partner with the University of Florida and your local County Government.
Send your question and bug photo to your local County Extension Office, and they will gladly answer all inquiries. To find an office near you, visit the Solutions for Your Life website, or contact us at firstname.lastname@example.org.