BOX THORN, KEY EARLY-SEASON HOST OF THE MEDITERRANEAN FRUIT-FLY

In the Mediterranean region, from November to early June, Mediterranea n fruit fly or medfly (Ceratitis capitata Wiedemann) populations decre ase drastically and in some places disappear. For area-wide control or eradication programmes, it is important to know on which wild hosts a medfly population can establish itself and subsequently cause later i n the season important losses in commercial crops. Trapping of medfly in a box thorn (Lycium europaeum L.) hedge of the oasis of Tozeur, Tun isia, indicates that despite this plant being largely neglected by med fly later in the year, it is a principal early-spring host of the pest . Fruit infestation rate in May was c. 292 pupae/kg of fresh fruits an d an average of two larvae per infested fruit. The trap capture rate w as c. 26 flies/trap/h. The importance of this non-commercial key-host in the development and distribution of medfly population during the ea rly season when no other host is available is discussed. The diurnal b imodal flight activity rhythm of medfly under high day temperature con ditions was confirmed.