Roger A. LeBrun Klaus Heyer Elyes Zhioua Howard S. Ginsberg 2002 <p class="p1"><span class="s1">The potential for nontarget effects of the entomopathogenic fungus <i>Metarhizium anisopliae</i> (Metschnikoff) Sorokin, when used for biological control of ticks, was assessed in laboratory trials. Fungal pathogenicity was studied against convergent ladybird beetles, <i>Hippodamia convergens</i> Guérin-Méneville, house crickets, <i>Acheta domesticus</i> (L.), and the milkweed bugs <i>Oncopeltus fasciatus</i> (Dallas). Fungal spores applied with a spray tower produced significant mortality in <i>H. convergens</i> and <i>A. domesticus</i>, but effects on <i>O. fasciatus</i> were marginal. Placing treated insects with untreated individuals resulted in mortality from horizontal transmission to untreated beetles and crickets, but not milkweed bugs. Spread of fungal infection in the beetles resulted in mortality on days 4–10 after treatment, while in crickets mortality was on day 2 after treatment, suggesting different levels of pathogenicity and possibly different modes of transmission. Therefore, <i>M. anisopliae</i> varies in pathogenicity to different insects. Inundative applications can potentially affect nontarget species, but <i>M. anisopliae</i> is already widely distributed in North America, so applications for tick control generally would not introduce a novel pathogen into the environment. Pathogenicity in lab trials does not, by itself, demonstrate activity under natural conditions, so field trials are needed to confirm these results and to assess methods to minimize nontarget exposure.</span></p> application/pdf 10.1603/0046-225X-31.6.1191 en Entomological Society of America Potential nontarget effects of <i>Metarhizium anisopliae</i> (Deuteromycetes) used for biological control of ticks (Acari: Ixodidae) article