May vine mealybug sex pheromone improve the biological control of the citrus mealybug ?

Abstract

It was recently showed that (S)-lavandulyl senecioate, the sex pheromone of the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), attracts the females of the parasitoid Anagyrus spec. nov. near pseudococci (Hymenoptera: Encyrtidae). In a further study we examined whether this behaviour increases parasitization of this wasp in citrus mealybug Planococcus citri (Risso), in citrus orchards. As an experimental tool we exposed, in field trials, sentinel mealybugs (3rd instar nymphs and adult females) on sprouted potatoes (= potato traps), to allow the access of the parasitoids to the mealybug colony. Three modalities were compared: 1) potato traps baited with dispensers loaded with the sex pheromone of P. ficus, 2) potato traps baited with dispensers loaded with the sex pheromone of P. citri, and 3) same trap design without pheromone (control). A similar set-up was conducted in citrus orchards in Portugal, Italy and Israel. Based on the number of trapped and emerged parasitoids and the minimal number of days of first parasitoid emergence we concluded that the presence of (S)-lavandulyl senecioate significantly increases the parasitization rate of P. citri colonies by Anagyrus spec. nov. near pseudococci. The results and their possible applications in future management of P. citri are discussed.