Proteins from the genus Photorhabdus are toxic to insects upon exposure. Photorhabdus luminescens (formerly Xenorhabdus luminescens) have been found in mammalian clinical samples and as a bacterial symbiont of entomopathogenic nematodes of genus Heterohabditis. These protein toxins can be applied to, or genetically engineered into, insect larvae food and plants for insect control.