Beware (but do not fear) the skeltonizer!
By Ralph E. Mitchell
Insect pests feed in a number of ways and caterpillars use chewing mouthparts to make their mark. One such caterpillar that does some real precision work is the palm leaf skeltonizer. This small drab caterpillar slowly eats the upper layers of palm frond tissue eventually skeletonizing the leaf leaving only bare bone veins. While a bit shocking to discover, the palm leaf skeletonizer is more of an eyesore than a real threat to the survival of the palm. However, you may still want to suppress this cryptic pest with some cultural techniques.
While palm leaf skeltonizers like to feed on Sabal palms the best, they will also get on Mexican fan palms, red latan palms, and coconuts on occasion. I found a small infestation on my own Sabal palm the other day and decided to take a closer look. It all started when a very small tan female moth laid eggs on the fronds. The resulting tiny cream-colored caterpillars fed between the veins on the underside of the frond eventually leaving transparent to translucent patches showing the parallel veins. As they grew, a mess of frass (caterpillar droppings) and silken tubes developed in which they hide and feed. Over time, these tubes extend out longer as the caterpillars find new green tissue to consume. Quite a large amount of frass and silk webbing will accumulate making it very visible to the eye.
The good news is that, with very few exceptions, the damage is only aesthetic in nature and chemical control is really not practical. Also, many beneficial parasites will eventually catch-up and keep this pest under control. Parasitic wasps and flies, as well as a predatory beetle, have been found feeding on palm leaf skeltonizers. Keeping the palm healthy is always a good idea, but if the feeding mess is more than you can bear, go ahead and hand-remove much of it with a stream of water from a hose and/or wipe it off with a wet sponge. This hand-grooming, in addition to frequent monitoring, should keep this pest at bay.
The palm leaf skeletonizer is one palm pest that should not frighten you. Although it may look unsightly and ever-expanding, it is limiting and highly manageable. For more information on all types of palm pests in our area, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer. Don’t forget to visit our other County Plant Clinics in the area. Please check this link for a complete list of site locations, dates and times – http://blogs.ifas.ufl.edu/charlotteco/files/2018/03/Plant-Clinics-Schedule.pdf. Ralph E. Mitchell is the Director/Horticulture Agent for the Charlotte County Extension Service. He can be reached at 941-764-4344 or firstname.lastname@example.org.
Howard, F. W. & Abreu, E. ( 2007) The Palm Leaf Skeletonizer, Homaledra sabalella (Lepidoptera: Coleophoridae) : Status and Potential Pest Management Options. University of Florida, IFAS. Proc. Fla. State Hort Soc. 120:356-359. 2007.
What’s Wrong with My Palm?! Palm Leaf Skeletonizer. (2013) Herb Creek Landscape – (Adapted from the University of Florida IFAS Extension).
Gabel, K. (2008) The Palm Leaf Skeletonizer. The University of Florida Extension Service – Monroe County.