Ants associated with Diaphorina citri and their role in its biological control in South Florida

As a vector of citrus greening, Diaphorina citri is considered  the major insect problem for the citrus industry in Florida. Two specific parasitoids of this pest has been introduced, but the parasitism rates are beyond  satisfactory. One of the reasons of this lack of control could be the interaction of the parasitoids with other arthropods present in the system. Ants (Hymenoptera: Formicidae) have been found already interfering with parasitoids with other Hemipteran pests.  In this research we identified and observed the behavior of ants present in Murraya paniculata infested flushes with D. citri during a 24 h period   and  we  conducted two experiments of ant exclusion using Tanglefoot as a physical ant barrier in both orange jasmine and  in Persian lime.  The results show at least  four species of ants are tending D. citri in South Florida. These species are:  Brachymirmex patagonicus, B. obscurior. Pheidole megachepala and Solenopsis invicta.   These ants are active day and night and were seen  feeding on the sugar excretions of D. citri  nymphs.  The results of the ant exclusion experiment show that the percentage of parasitism by Tamarixia radiata was significantly higher in the flushes where ants were excluded. We discuss if ant exclusion would be a technique that citrus growers can use as a tactic to increase parasitism of D. citri.