Pike, Thomas JohnBrown marmorated stink bug, Halyomorpha halys, is an invasive stink bug native to Asia. It is a highly destructive pest in both agricultural and ornamental systems. In an effort to identify a novel biological control, several strains of entomopathogenic fungi were tested against brown marmorated stink bug nymphs and adults. Wild-type fungi were found to cause very low mortality in bioassays, as well as resulting in little fungal growth or sporulation. The addition of diatomaceous earth and/or horticultural oil did not increase mortality, nor did the use of transgenic fungi. To test the proposed mechanism of brown marmorated stink bug's defense against fungal infection, trans-2-octenal and trans-2-decenal were bioassayed against several strains of entomopathogenic fungi. These compounds were found to inhibit fungal growth and prevent spore germination at low concentrations. Results of an experiment to determine if brown marmorated stink bug responded to fungal exposure were inconclusive.enThesisEntomologyBMSBentomopathogenicfungistink bug