powdery mildew: any of various fungi of the genus Erysiphe producing powdery conidia on the host surface
fungus: an organism of the kingdom Fungi lacking chlorophyll and feeding on organic matter; ranging from unicellular or multicellular organisms to spore-bearing syncytia
central intelligence agency: an independent agency of the United States government responsible for collecting and coordinating intelligence and counterintelligence activities abroad in the national interest; headed by the Director of Central Intelligence under the supervision of the President and National Security Council