Ganoderma orbiforme – most commonly known as G. boninense or just Ganoderma in oil palm pathology – is a species of polypore fungus that is widespread across southeast Asia. It is a plant pathogen that causes basal stem rot, a disease of the African oil palm. The fungus was first described scientifically in 1838 by Elias Magnus Fries from collections made in Guinea. Leif Ryvarden transferred it to the genus Ganoderma in 2000. In addition to its type locality, the fungus has also been collected from the Bonin Islands in the Pacific, and from Venezuela and Puerto Rico.

Plant diseases are diseases in plants caused by pathogens and environmental conditions. Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are ectoparasites like insects, mites, vertebrates, or other pests that affect plant health by eating plant tissues and causing injury that may admit plant pathogens. The study of plant disease is called plant pathology.