Josephiella Wasp Galls on Ficus

Wasp galls on Ficus microcarpa caused by Josephiella microcarpae. Upper leaf surface. <UF Laura Sanagorski>

Here’s another Ficus pest that likes our Cuban Laurels.  These galls are caused by the Josephiella wasp (Josephiella microcarpae).  This wasp was first identified in Hawaii in the late 1980’s (read here: A new species of Josephiella (Hymenoptera Agaonidae) forming leaf galls) and then in Florida in 2007.  Most often, galls are merely aesthetic issues, such as in the case of the harmless  Sea Grape Blister Galls.  In general, leaf galls are less damaging to trees and plants than stem galls.  This gall caused by the Josephiella wasp, can cause defoliation of Ficus plants and trees, so treatment may be necessary, especially if this pest is present in combination with Ficus Whitefly or other types of stress.  Systemic insecticides may be helpful in managing this gall-forming wasp.  Neonicotinoids have been used for gall insects but there is no documentation on its use for this insect.  Imidacloprid is one possible suggestion for treatment.  Remember that treatment for gall-makers will not get rid of the galls.

Wasp galls on Ficus microcarpa caused by Josephiella microcarpae. Lower leaf surface. Look closely for exit holes caused by emerging adults. <UF Laura Sanagorski>

The Josephiella adult female lays her eggs in Ficus leaf tissue; immature wasps feed on a leaf’s nutrients, causing swelling in the leaf tissue.  When the adults emerge, they leave tiny holes on the undersides of leaves.  Dr. Doug Caldwell, Commercial Landscape Horticulture educator with UF / IFAS Extension in Collier County, wrote an excellent article, Ficus Trees Under Attack!, about this and other Ficus disorders. 

If you see signs of this gall wasp on your customers’ ficus hedges and trees, you may not need to treat, but its good to know what you’re dealing with.