UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail:  indianco@ufl.edu

February 18, 2004

Feature Article - for release the week of February 22, 2004

Dan Culbert - Extension Horticulture Agent

This past week an office visitor came by with a baggie filled with thorns that were crawling all over his Powderpuff. For many it would mean that he was insane, but I knew exactly what he was talking about - another sign of spring!

Powderpuffs are attractive bushes with fluffy flowers occasionally found in our Florida Yards. And, in the spring, they are often found to be covered with an insect that looks like a thorn, which is why they are called thornbugs. While these insects may cause some grief to plants and to homeowners, rarely in my experience have they caused harm to the plants they are found on. Today’s column will discuss this common host plant and its interesting companion.

It’s surprising to me that more people don’t consider planting Powderpuffs in their Florida Yards. These multi-stemmed evergreen bushes grow to 10-15 feet in height, and they produce puffy balls of red, pink and sometimes white colored flowers. Since it is a member of bean family, Calliandra haematocephala will occasionally produce 3 to 6 inch long pods with seed.

They are not fussy as to their soil or light preferences, but they will do better if placed away from busy areas where the thin bark could be damaged. Pruning may be needed if a single-trunked "tree" form is desired, and a stronger canopy can result from selective removal of suckers and poorly attached branches.

Few pests bother Powderpuffs. They may play host to the various sucking insects that can result in black sooty mold, but these are easily managed by the use of horticultural oils and insecticidal soaps. So what’s this about these thorn bugs?

In my experience, one of the rites of spring is the arrival of large thornbug populations on Powderpuffs. There are references that say large numbers of these insects have caused damage to young Jacaranda and Poinciana trees, but little evidence that they permanently bother powderpuffs or other popular thornbug hosts: hibiscus, acacias, bottlebrush, citrus and avocados. Damage from this insect could be caused by sucking the sap and by the cuts made in the bark from the thornbug’s egg-laying.

One author [Bill Zak, author of Florida Critters] calls this insect the Cat’s Claw Thornbug. So what does it look like? It’s a lime green thorn with wings that have some dark green, brown or black stripes. Adult thornbugs are about one-half inch long and have a sharp bump on their back, which make it look like it was peeled off a rosebush. The males have a broader tip to the thorn than the females. They all have spines on their shoulders. There is one report that barefoot children walked on thornbugs that fell out of trees and got some nasty infections from the puncture wounds - but this report came from the 1960's.

Thornbugs are true bugs, which means the young nymphs look like smaller version of the adults, but are red to brown in color. All true bugs are sapsuckers- they have a straw-like mouthpart that is used to drink sap from their host plant. The waste material they leave behind, called honeydew, can support a black superficial fungus called honeydew on the leaves.

The sudden appearance of large numbers of thornbugs and the honeydew may scare some homeowners, but large populations of these insects will soon crash. If you have to do something about them, try collecting and placing them in a sealed bag in a trash container. If you must use insecticides, try the horticultural oils and soaps first. If the relief is not enough, products labeled for ornamentals such as acephate (Orthene™), carbaryl (Sevin™), cyfluthrin (Tempo™) or imidacloprid ( Merit™) will rapidly remove these thorny critters.

Master Gardeners can answer your questions about powderpuffs, thornbugs or your Florida Yard - call or visit them on Tuesday afternoons here at our office. If you need additional information, visit out webpage at http://okeechobee.ifas.ufl.edu , or stop by 458 Hwy 98 North in Okeechobee. Our phone number is (863) 763-6469, and you can email us at okeechobee@ifas.ufl.edu .

References

Gilman, Ed. Powderpuff (Callandra haematocephala ). Gainesville: UF/IFAS Southern Trees Fact sheet ST-108. November 1993. http://hort.ifas.ufl.edu/database/documents/pdf/tree_fact_sheets/calhaea.pdf 

ibid. Pink Powderpuff ((Callandra  surinamensis). Gainesville: UF/IFAS Southern Trees Fact sheet ST-109. November 1993. http://hort.ifas.ufl.edu/database/documents/pdf/tree_fact_sheets/calsura.pdf 

ibid. Dwarf Red Powderpuff (Calliandra haematocephala ‘Nana’). Gainesville: UF/IFAS Fact sheet FPS-89. October, 1999. http://hort.ifas.ufl.edu/database/documents/pdf/shrub_fact_sheets/calhaec.pdf 

Ibid. White Powderpuff (Calliandra haematocephala ‘Alba’). Gainesville: UF/IFAS Fact sheet FPS-88. October, 1999. http://hort.ifas.ufl.edu/database/documents/pdf/shrub_fact_sheets/calhaeb.pdf

Mead, F.W. and Fasulo, Thomas R. Thorn bug (Umbonia crassicornis). Gainesville: UF/IFAS Featured Creatures Fact sheet EENY-175. November, 2000. http://entomology.ifas.ufl.edu/creatures/orn/thorn_bug.htm.  [Originally published as FDACS DPI Entomology Circular 8. (November 1962)  http://www.doacs.state.fl.us/pi/enpp/ento/entcirc/Entcirc8.pdf ]

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