DIET PH EFFECTS ON MASS REARING OF MEDITERRANEAN FRUIT-FLY (DIPTERA, TEPHRITIDAE)

The effects of dietary pH on larval development of the Mediterranean f ruit fly Ceratitis capitata (Wiedemann), were studied in laboratory an d pilot scale mass-rearing operations. Laboratory scale diets were for mulated at eight different initial pHs ranging from 3.2 to 8.0, and th e effect on larvae were evaluated based on larval development time and pupal yield. Optimal larval development occurred at pH 5.0-5.5 and pu pal yield was highest between 3.2 and 5.5. Diet pHs of 6.0 or higher w ere found to delay larval development and reduce pupal survival. Diet pHs of 3.2 and 4.0 also delayed larval development. Pilot-scale evalua tions were subsequently conducted at pH 4.0 and 5.0 and compared with the normal Animal and Plant Health Inspection Service production diet for cumulative yield and pupal weight. Optimal diet pH for pupal size, larval yield, and rapid development was determined to be 5.0 in pilot -scale tests. Optimizing physiochemical factors such as pH can improve overall yield of mass-reared C. capitata.