Photo credits: Cesar Calderon, USDA APHIS PPQ, Bugwood.org – This image is Image Number 2177071 at Forestry Images, a source for forest health, natural resources and silviculture images operated by The Bugwood Network at the University of Georgia and the USDA Forest Service.
Teleospores of the Wheat Rust (Puccinia gramini). CC BY 3.0 us via Wikimedia Commons