Spring 2015 Field Observations: Ficus eye-spot midge
Regional Report San Diego and Riverside Counties by James A. Bethke
Recently, a new established pest has been confirmed and observed in the cities of San Diego, Rancho Santa Fe, Del Mar and LaJolla. Dr. Tracy Ellis, San Diego County Department of Agriculture Weights and Measures entomologist, sent samples of Ficus microcarpa from the landscape (fig. 1) and a local nursery to the California Department of Food and Agriculture Plant Pest Diagnostics Lab, and the pest was identified as an eye-spot midge (fly species, family Cecidomyiidae), Horidiplosis ficifolii Harris. This is the first report of this pest in California, but it was found in Florida in 2008. Interestingly, it was found on F. microcarpa in Florida and not on F. benjamina growing directly below the F. microcarpa. It was first described in 2003, and originates from China, Taiwan and Japan.
Fig. 1. Damaged terminal leaves high in a Ficus microcarpa tree in the landscape caused by an eye-spot midge, Horidiplosis ficifolii Harris. Photo: Tracy Ellis, San Diego County Department of Agriculture Weights and Measures entomologist.
The tiny fly maggot lives inside the blister-like gall (fig. 2), eventually causing a necrotic spot that in some cases resembles an eyespot, a dark center with a light-colored ring around it. Each spot contains one midge larva. As the damage progresses, leaves begin to drop from the trees.
Fig. 2. Necrotic wound damage to leaves of Ficus microcarpa cause by the eye-spot midge, Horidiplosis ficifolii Harris. Photo: Tracy Ellis, San Diego County Department of Agriculture Weights and Measures entomologist.
It appears that a couple of ficus pests moved here from Florida in the last few years. It’s hard to say whether they are being transported by immigrating Floridians or the ornamental plant trade, but it would be worthwhile scrutinizing shipments of Ficus spp. coming from Florida.
For more information about the eye spot midge on ficus, see the pest alert from Florida: http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Plant-Industry-Publications/Pest-Alerts/Pest-Alerts-An-Ornamental-Fig-Pest-Horidiplosis-Ficifolii-Harris-Diptera-Cecidomyiidae.
James A. Bethke
Farm Advisor, Nurseries and Floriculture
UC Cooperative Extension San Diego, North County Office
151 E. Carmel St., San Marcos, CA 92078
(760) 752-4715 phone; (760) 752-4725 fax