Pileolaria brevipes

{{Short description|Species of fungus}}

{{Speciesbox

| image = Poison ivy rust imported from iNaturalist photo 135801927 on 14 March 2024.jpg

| genus = Pileolaria (fungus)

| species = brevipes

| authority = Berk. and Rav.

| synonyms = P. toxicodendri

}}

Pileolaria brevipes, also known as poison ivy rust, is a species of autoecious fungus in the order Pucciniales.{{cite web |title=Pileolaria brevipes (Poison ivy rust) |url=https://www.inaturalist.org/taxa/351853-Pileolaria-brevipes |access-date=2024-03-14 |website=iNaturalist |language=en-US}} Pileolaria brevipes parasitizes Toxicodendron diversilobum and Toxicodendron radicans.{{Cite journal |last=Gillis |first=William T. |date=1971 |title=THE SYSTEMATICS AND ECOLOGY OF POISON-IVY AND THE POISON-OAKS (TOXICODENDRON, ANACARDIACEAE) (Continued) |url=https://www.jstor.org/stable/23311725 |journal=Rhodora |volume=73 |issue=796 |pages=465–540 |jstor=23311725 |issn=0035-4902}} The color of this rust comes from "its asexual spores called urediospores". Poison ivy rust infections become evident in spring as "light pink to dark red swellings on leaflet veins or petioles. By late June, swellings have darkened to brown, and grown. The leaflet or leaf typically exhibits a curled morphology and oftentimes is wilted. Individuals infected with P. brevipes are less prone to flower compared to adjacent, noninfected congeners".{{Cite journal |last=Senchina |first=David S. |date=July 2008 |title=Fungal and animal associates of Toxicodendron spp. (Anacardiaceae) in North America |url=https://linkinghub.elsevier.com/retrieve/pii/S1433831908000334 |journal=Perspectives in Plant Ecology, Evolution and Systematics |language=en |volume=10 |issue=3 |pages=197–216 |doi=10.1016/j.ppees.2008.02.001|url-access=subscription }}

Damaging arthropod associates of Toxicodendron species include Epipaschia zelleri and the poison ivy sawfly.