An Ornamental Fig Pest , Horidiplosis ficifolii Harris (Diptera: Cecidomyiidae), Genus and Species New to Florida and North America
Gary J. Steck, steckg@doacs.state.fl.us , Taxonomic Entomologist, Florida Department of Agriculture and Consumer Services, Division of Plant Industry;
Scott Krueger, krueges@doacs.state.fl.us, Environmental Specialist I, Florida Department of Agriculture and Consumer Services, Division of Plant Industry
INTRODUCTION: Elliptical blister-like galls were found on leaves of Indian Laurel, Ficus microcarpa L. F. in Naples ( Collier County , E2008-112; Scott Krueger, 4 January 2008 ). As the gall morphology did not match that of any gall midges previously reported from Ficus in North America (see Gagné 1989), fresh galled leaves were sent to Dr. Raymond J. Gagné (retired, Systematic Entomology Laboratory, USDA-ARS , Washington DC) for closer examination and rearing to the adult stage. On 20 February 2008 , he successfully reared adults and determined them to be Horidiplosis ficifolii Harris (Diptera: Cecidomyiidae).
This gall midge is relatively new to science, having been described only in 2003 (Harris and DeGoffau 2003) based on material originating in Taiwan, Japan, and China and intercepted by plant health inspectors in the Netherlands and Denmark.
DESCRIPTION: Gall midges apparently attack the young leaves which may become discolored, pocked with brown, blister-like lesions and severely disfigured (Fig. 1). Heavily infested leaves may drop from the plant. The gall midge larvae feed inside the blisters, and only one larva has been found in each blister. They are tiny (2 mm or less), white in their early stages and become bright orange as they mature (Fig. 2).
HOSTS: The specimens upon which the description of Horidiplosis ficifolia was based were reared from bonsai Ficus benjamina L., which originated in Taiwan and China. In Florida, the galls have been found only on F. microcarpa as bonsai plants in at least one nursery and on large trees in the landscape. Curiously, although F. benjamina is very abundant, comprising probably many miles of hedges in the Naples area, and even where it grows under infested F. microcarpa trees, it has not been found to be infested. We cannot rule out the possibility that the Florida gall midges represent a different, undescribed and cryptic species of Horidiplosis.
BIOLOGY AND ECONOMIC IMPACT: Nothing has been published on the biology or economic importance of this gall midge. As various species of Ficus are very important container and landscape plants in much of Florida and elsewhere, H. ficifolii may become a serious pest to the commercial ornamental industry.
DISTRIBUTION: The genus Horidiplosis contains six oriental species, primarily from India, and all are associated with figs.
FLORIDA DISTRIBUTION: Horidiplosis ficifolii presently is known only from Collier County, where it is apparently widespread in the vicinity of Naples.
Fig 1. Galled leaves of Ficus microcarpa.
Fig 2. Gall midge larvae in leaf blisters on Ficus microcarpa.
REFERENCES CITED:
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Gagné, R. J. 1989. The plant-feeding gall midges of North America. Cornell University Press, xi + 356 p.
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Harris, K.M. and L. J. W. DeGoffau. 2003. Horidiplosis ficifolii, a new species of gall midge (Diptera: Cecidomyiidae) damaging ornamental fig plants, Ficus benjamina L. Tijdscrift voor Entomologie 146: 301-306.
Page created 20-March-2008
Photographs by G. J. Steck
