Balance the need to get rid of the orange dog caterpillar with having butterflies in your yard.

How to Get Rid of an Orange Dog Caterpillar

by Veronica Smith-Jennings

Unfortunately for the orange dog caterpillar (Papilio cresphontes), its claim to fame is an uncanny resemblance to bird droppings. But before you turn up your nose, this is also the caterpillar that transforms itself into a swallowtail butterfly, with a beautiful, dramatic pattern and a 6-inch wingspan. You may find the orange dog caterpillars on citrus trees (Citrus spp.), annual fennel (Foeniculum vulgare) and prickly ash (Zanthoxylum spp.). Smaller trees could sustain lasting damage -- a few caterpillars can eat all the leaves from a small potted citrus tree. Large trees won't suffer from losing some leaves to the orange dog, though. You can get rid of orange dogs without using chemicals -- and you can leave a few to change into butterflies that will surely entertain your children.

Look for single eggs on small trees and crush them by hand. Eggs look like tiny spheres and are cream to brown or sometimes yellow. You can find them on the leaves' upper surfaces.

Pick orange dog caterpillars off of the leaves by hand or with tweezers. Crush them or put them in a jar filled with rubbing alcohol or a mixture of dish soap and water.

Sprinkle Bacillus thuringiensis powder onto the affected leaves until they are lightly coated. Apply Bt on all affected foliage in April. When the caterpillars eat it, they will die within days. This kills caterpillars that have recently hatched. Bt is a naturally occurring bacteria, effective in killing leaf-eating caterpillars. It is not dangerous to humans, and will not harm other beneficial insects.

Items you will need

  • Tweezers
  • Jar
  • Rubbing alcohol
  • Dish soap
  • Bacillus thuringiensis powder


  • Citrus trees grow in U.S. Department of Agriculture plant hardiness zones 9 through 11, prickly ash grows in USDA zones 3 through 7.

About the Author

Veronica Smith-Jennings is a former teacher who started freelance writing in 2003 and has been published in regional parenting magazines as well as on various websites. Her writing interests include home renovation and gardening, politics, education, sports and early childhood development. She has a Master of Arts in English education and a Bachelor of Arts in English.

Photo Credits

  • Hemera Technologies/ Images