Citrus Tree With Mediterranean Fruit Fly Symptoms

Mediterranean fruit fly larvae feed on citrus fruits

If soft, rotting fruits are prematurely falling from your citrus tree, the Mediterranean fruit fly (Ceratitis capitata) may be the culprit. The Mediterranean fruit fly, or medfly, infests over 200 different hosts, including citrus trees. According to the University of Florida Extension, it is the world's most economically damaging fruit fly. Affected areas face quarantines and crop loss, as well as detection and management expenses.

Features

A little smaller than a housefly, an adult Mediterranean fruit fly has clear wings with brown or black speckles. Its thorax, or chest area, is yellowish white, and its abdomen is tan with dark stripes. An adult fruit fly deposits small white eggs under the skin of fruit that is not fully ripened. A scar may form in the fruit. The white, legless larvae hatch from the eggs and deposit a rot-inducing bacteria into the fruit. The larvae then tunnel through and feed on the infected fruits. Infested fruits soften and fall to the ground.

Time Frame

The medfly completes its life cycle in 21 to 30 days. According to the University of Florida Extension, female fruit flies continue to deposit eggs as long as the trees bear fruit and as long as temperatures remain above 60.8 degrees F. Immediately after hatching, the larvae begin to feed on the fruit pulp. After the fruit falls to the ground, the pupae develop into mature fruit flies. Growers may avoid infestation by planting early season citrus varieties, which produce fruit before the temperature is warm enough for medfly reproduction.

Geography

Jet transportation has quickly distributed the medfly from its native Africa to a wide range of areas, including the United States, Australia, Europe and Central America. The medfly first appeared in Hawaii in 1910 and in Florida in 1929. Texas and California have also experienced infestations and quarantines. The United States Department of Agriculture conducts ongoing trapping programs in high risk areas, and imposes quarantines when the Mediterranean fruit fly is detected.

Solution

If your citrus tree shows signs of infestation, contact a USDA or state agriculture official at the number listed in the government sections of your phone book. Government agriculture officials use sticky traps to detect adult flies in areas at risk of infestation. Once an infestation is confirmed, federal and state officials impose quarantines on fruits from the area. Control measures include removal of all fruits from infested property, as well as pesticide applications on trees and soil, and the release of sterile fruit flies into the area.

References

• University of Florida Extension: Mediterranean Fruit Fly, Ceratitis capitata (Wiedemann); M.C. Thomas, et al.; 2009
• United States Department of Agriculture: Mediterranean Fruit Fly
• California Agriculture: On the California Border, Exotic Pests Pose Growing Problem for California Agriculture; Robert V. Dowell and Conrad J. Kress; January 1992
• United States Department of Agriculture: Mediterranean Fruit Fly; May 1999

Resources

• United States Department of Agriculture: Mediterranean Fruit Fly Quarantine Information