Kaolin affects blueberry maggot behavior on fruit.

This study assessed the effects of Surround (kaolin) on several behavioral parameters of female blueberry maggot, Rhagoletis mendax Curran (Diptera: Tephritidae). First fruit visited, walking, cleaning, and oviposition behavior were quantified in two-choice and no-choice assays where females encountered Surround-treated and untreated fruit of highbush blueberries (Vaccinium spp.). In two-choice assays, females had a propensity (68%) to first visit untreated blueberries. In two-choice and no-choice tests, number of walking bouts and duration of walking bouts were significantly shorter on the Surround-treated than on untreated fruit. Few oviposition attempts on fruit were observed, irrespective of treatments and assays. Chromameter measurements showed significant modification of the blueberry skin color parameters lightness, hue, and saturation between untreated fruit compared with fruit dipped once or twice in a suspension of Surround. Oviposition trials with field-treated fruit showed that blueberries treated with Surround had fewer oviposition scars than the control, and this was more pronounced with weekly applications of Surround. Uneven coating of the fruit by Surround in field applications may have resulted in higher acceptance rates by flies than in blueberries individually dipped and used in laboratory trials.