(News article for December 2018)
Have you noticed something eating your citrus tree leaves lately? The culprit is most likely the orange dog caterpillar. I saw a couple of small citrus trees completely defoliated by this little beast! The orange dog caterpillar looks like bird droppings on citrus tree leaves. They aren’t very cute in the larva (caterpillar) stage but after pupation they become the beautiful Heraclides cresphonte; known commonly as the Giant Swallowtail butterfly.
When the caterpillar feels threatened it will send up two red scent glands from its head, hence the name orange dog caterpillar. The glands are to discourage birds and other predators from eating them.
Giant Swallowtail butterflies lay their eggs, one at a time, on citrus trees and related plants. You can see their eggs with the naked eye.Look for a solitary tiny, orange egg, slightly bigger than a mustard seed. The caterpillars and eggs are fun to collect to observe the pupation process. You can buy a butterfly enclosure or rig one up yourself. There are numerous examples on the internet. Even though the caterpillars look eerie, they are harmless and will not sting. Be sure to leave them plenty of citrus leaves to munch on, along with limbs for them to attach their chrysalis to. In the pupal stage, the butterfly caterpillar sheds its skin and forms a chrysalis whereas a moth caterpillar will spin a silk cocoon.Orange dog caterpillar damage to citrus trees is usually minor. Unless you have a very young tree with few leaves, leave the caterpillars alone and enjoy the Giant Swallowtails in a few weeks. If you are worried about complete defoliation of a young tree, you can pull the caterpillars off and dispose of them, spray with Bt (Bacillus thuringiensis) to control them, or transfer them to a larger tree that can withstand the pressure.
Everyone wants their plants to look perfect but not all insects are bad. Enduring a few chewed up leaves now will ensure a spectacular butterfly show in a few weeks. If you would like to learn more about butterflies and other pollinators I encourage you to attend Pollination Celebration at the LSU AgCenter Hammond Research station on Saturday, September 15, 2018. The event is from 9:00 am to 3:00 pm and will feature hand-on activities and educational seminars on all things pollination. The cost for Pollination Celebration is $5 per car and food, plant, and craft vendors will be available. The research station is located at 21549 Old Covington Highway, Hammond, LA 70403.
Jessie Hoover is a County Agent with the LSU AgCenter covering horticulture in East Feliciana, West Feliciana, St. Helena, and Tangipahoa parishes. For more information on these or related topics contact Jessie at 225-683-3101 or visit the LSU AgCenter website.
Giant swallowtail butterfly. Photo by: Donald Hall, University of Florida Featured Creatures.
Orange dog caterpillar. Photo by: Donald Hall, University of Florida Featured Creatures.