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I’ve discussed ficus problems recently and normally wouldn’t repeat so soon. However, in early March, during my trouble-shooting property inspections which I make at the request of landscape-maintenance companies, I’ve observed a rather alarming amount of insect activity and felt that the citizens should be aware of the severity of what I’d call a double-barreled outbreak. About 90 percent of the ficus hedges I’ve observed have about 70 to 80 percent of the new foliage distorted by these insects which could result in significant leaf-drop and twig dieback, as the insects have repeating generations and just don’t go away after a few months.

Both the Cuban-laurel (Ficus microcarpa or retusa) and the weeping fig (Ficus benjamina) have separate insect pests that may cause some defoliation.

The new blister leaf gall arrived for the first time in Florida, in Naples of course, in early 2007 and attacks only the Cuban laurel. It is caused by a small wasp about 1.5 mm long in the genus Josephiella. The galls consist of a series of bumps that may run together and distort the foliage. This may develop into more than an aesthetic issue, as I originally described it in a June 23, 2007, column. The female wasp “stings” the foliage and inserts eggs. As the larvae grow, the plant tissue swells around each larva and provides nourishment. Information is lacking on the biology of this pest.

Most landscapers are familiar with the common leaf distortion on Cuban laurel caused by a little black thrips from Southeast Asia. The leaf responds to the sucking-type feeding of this thrips by folding upward along the midvein. This results in a misshapen leaf roll that resembles a pea pod. Because this gall doesn’t normally become very abundant, it is of little concern.

Our ever-abundant weeping fig wasn’t bothered by this Cuban laurel thrips. In 2003, another species of thrips arrived from Southeast Asia. This one makes a similar leaf-roll distortion, but only on the weeping fig leaves. In the June 2007 column, I stated, “This damage hardly affects these vigorous ficus trees.”

But then, there are more insects on the way: both the ficus whitefly and fig wax scale are causing dieback of trees and hedges in the Miami and Homestead areas. For more on these various pests, go to:

creatures.ifas.ufl.edu

www.doacs.state.fl.us/pi/enpp/pi-pest-alert.html.

What to do: Because these insects are protected by plant tissue, the wasp larvae inside a fleshy gall and the thrips inside the folded leaf, most types of foliar applications won’t affect them. A product with acephate, which is mildly systemic, may reduce numbers, but certain formulations of this insecticide can have a strong sulfur odor (I’m being polite here!). Foliar applications of products with spinosad may help.

Either foliar or soil applications of products with imidacloprid or dinotefuran (see editor’s note below) may help also. The soil treatments will be pricey, but should provide longer results, say six months, instead of 10 to 14 days with foliar applications.

Stay tuned until we learn more about these pests. Hopefully, we will have some natural predator or parasitic insects that will enter into the picture and minimize the damage these pests are causing.

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Doug Caldwell, Ph.D., is the commercial landscape horticulture extension agent and landscape entomologist with the University of Florida Collier County Extension Service. E-mail dougbug@ufl.edu; phone, 353-4244 x203. For updates on Southwest Florida Horticulture visit: collier.ifas.ufl.edu

Editor’s note: Please see the Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University, for information on these chemicals and what their effects on other wildlife and insects at this site:

extoxnet.orst.edu