<p class="HeadingRunIn"><strong>A novel use of predatory mites for dissemination of fungal pathogen for insect biocontrol: The case of <em>Amblyseius swirskii</em> and <em>Neoseiulus cucumeris </em>(Phytoseiidae) as vectors of <em>Beauveria bassiana</em> against <em>Diaphorina citri</em> (Psyllidae)</strong></p>

This study tests the novel use of predatory mites for dissemination of a fungal pathogen for insect biocontrol in the laboratory. We first evaluated the pathogenicity of Beauveria bassiana at several spore suspension concentrations against the nymphs of both the Asian citrus psyllid (Diaphorina citri) and two predatory mite species (Amblyseius swirskii and Neoseiulus cucumeris). The B. bassiana spores at suspension concentrations greater than 104 spores · ml-1 were highly effective against D. citri nymphs, resulting in a mortality approaching 100% after 7 days, but caused only low mortality rates of A. swirskii and N. cucumeris nymphs (15 and 10%, respectively) after 7 days. We then observed whether these two predatory mites, when dusted with B. bassiana spores, could disseminate the pathogen to D. citri residing on small twigs of potted Murraya paniculata (Rutaceae) plants under high humidity conditions. Several days after the release of "dusted" A. swirskii and N. cucumeris females, most D. citri had been killed by B. bassiana. As these phytoseiid predators exhibit a relatively high tolerance to this pathogen and are attracted to D. citri, we believe that this method might represent a new technique for using the Beauveria to control this pest insect. This method should be further explored for dissemination of entomophagous fungi to various insect pests in greenhouse and field conditions.