Season, Hour of Release and Holding Time as Determinants of Persistence of Mass Reared, Sterilized Mexican Fruit Flies (Diptera: Tephritidae) at a Release Site

Persistence of mass-reared, radiosterilized Mexican fruit flies, Anastrepha ludens (Loew), released at a target site was measured by trap-back. Released flies persisted in greater numbers during the winter months, with lowest numbers recovered in the summertime. Nocturnal releases were equally effective as morning releases in terms of persistence. Afternoon releases yielded better results in the winter but should be avoided in summer. Lowest persistence occurred in months with temperature extremes.