Suppression of the Mediterranean Fruit Fly in Tunisia with Released Sterile Insects12

Abstract

The Government of Tunisia, U.S. Agency for International Development, and U.S. Department of Agriculture cooperatively developed a program for suppression of Ceratitis capitata (Wiedemann) in Tunisia. Mediterranean fruit flies were reared on an artificial diet, sterilized with 10 krad irradiation from a cobalt source, and the emerged adults were marked and then distributed by hand throughout the release area, 600 ha in the vicinity of Porto-Farina. Some aerial releases were made late in the season. Winter larval hosts were removed to lower the over-wintering population, and sterile fly releases were begun early (Mar. 1) to prevent fertile matings of flies which emerged during warm winter days. All fruit on the periphery of the release area was sprayed periodically (5 applications), as was the major fruit-growing areas within the region but outside the test zone, to minimize the possibility of fertile flies entering the release area. Daily from March to November, ca. 1,000,000 sterile flies were released. Trap catches indicated that the suppression obtained was about equal to that obtained using poison bait sprays. The early preferred host crops had no or negligible infestation (loquats, apricots, early peaches, and figs). The infestation of preferred summer fruits (peaches and figs) was reduced but not controlled. Less susceptible summer fruits were seldom infested. The estimated population was ca. 82.3% lower than in the previous year when no releases were made. Isolation and sterile fly distribution was inadequate to completely suppress the Mediterranean fruit fly population.