In a constant race to overcome pesticide resistance by pests and pathogens, this research aimed to discover bioactive inhibitory compounds from natural products. I tested extracts from 10 different fungal isolates that were previously shown to have antifungal activity, and 5 commercially available natural products. Assays were developed to test natural products for antibiotic activities against model pathogens and pests including fungi, insects, and molluscs. The objectives of this research were to develop and determine the effectiveness of bioassays, and to identify potentially interesting natural products. Of the 10 fungal isolates tested, reconstituted broths of Penicillium virgatum, Ramularia vizellae, and Trichoderma sp. showed pronounced anti-fungal activity. Further, P. virgatum and Trichoderma sp. shows anti-insect activity while broths of Ramularia vizellae and Trichoderma sp. exhibited anti-mollusc activity. A preliminary metabolomic study identified potentially interesting metabolites that requires further investigation to determine the chemical structure(s), mode of action, and other attributes.