Control of Bactrocera oleae and Ceratitis capitata in Organic Orchards: Use of Clays and Copper Products.

Tests on the effect of clays (kaolin and bentonite) and copper products (hydroxide and oxychloride) in the control of olive fruit fly, Bactrocera oleae (Rossi), and Mediterranean fruit fly, Ceratitis capitata (Wiedemann), were carried out from 2003 to 2006 in olive groves and in organic citrus orchards (satsuma, clementine, ‘Navelina’ orange). Results demonstrate an efficacy of kaolin products in reducing attacks of B. oleae on olives and those of C. capitata on citrus fruits; in olive groves the clays gave similar or better results than copper hydroxide. Bentonite AG/8W showed a significant reduction in punctures by C. capitata. Bentonite products and BPLK kaolin are washed off by rainfall more easily than Surround WP kaolin. In contrast to the effect of copper hydroxide on B. oleae in olive groves, no tested copper product showed a significant reduction in C. capitata punctures on citrus fruits. Clays are very useful tools to control tephritid and other insects and are also environmental friendly, but currently, they are not permitted as products for plant protection in European and Swiss organic farming.