Eggs: The eggs are bright orange, translucent, about 0.6 mm long by 0.08 mm wide, and average 15 eggs per cluster.
Larvae: The larvae when newly hatched are light orange, about 0.6 mm long by 0.09 mm wide. At this point the sternal spatula is not visible but becomes visible as larvae mature, it then changes color to orange-red and reaches about 1.5mm long by 0.072mm wide.
Pupae: The pupae are obtect (wings and appendages are appressed to the body ) and bright orange. Males and females are approximately 1.53mm and 1.84mm long, respectively.
The oval shaped galls are formed on the terminal portion of the branchlets. When mature they resemble miniature pineapples that look like elongate swellings on the leaflets. The color varies from pink at first, turning light green as development progresses. However, the galls appear white most of the time because of a covering of fine, powdery material. When adults emerge the galls turn brown. Overwintering galls are usually copper-brown, dropping with branchlets in late autumn. The galls average 20 mm in length, but larger galls may reach 3 cm in length and 2 cm in width and may contain an average of 16 larvae. The number of midge larvae inside is highly correlated with the length of the gall. The gall tissue is spongy and succulent but becomes less succulent as the midge larvae mature.
The flies overwinter as larvae on the ground in the fallen galls in early November and pupate in mid-April inside the galls.
Adults flies emerge in mid-May for an extended period of time. Nearly 95% of the adult midges emerge within three weeks of the onset of emergence. Copulation occurs the same day as adult emergence. After mating, the female midge flies to the leaves where it oviposits on the new developing foliage an average of 120 eggs during their one to two day life span.
The midge larvae induce gall formation by the leaflets initiating as pink swellings of the branchlets at the feeding sites. Galls rapidly increase in size during the first three weeks and at the same time, larvae gradually move toward the longitudinal axis of the gall where each larva makes a small chamber which it occupies. Before pupation, the larvae reverse their position so that their heads point toward the gall surface.
For adult emergence, the pupa moves through the larval chamber and breaks the gall surface until its head and thorax are completely outside. The second generation feeds until mid-September and in late October the galls and foliage fall from the trees.
Insecticide applications are not recommended because high populations are often regulated by natural enemies that emerge at the same time as the midges such as the following parasitoids:
Authors: Celina Gomez and Russell F Mizell III, University of Florida
Photographs: Russell F Mizell III, University of Florida; and Albert Mayfield, Florida Department of Agriculture and Consumer Services
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-430
Publication Date: April 2008
Copyright 2008 University of Florida
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Department of Entomology and Nematology
Division of Plant Industry
Electronic Data Information Source
galls
gall
damage
drooping branch