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Doctrine of Signatures

(Encyclopedia)Doctrine of Signatures, the concept that the key to humanity's use of various plants was indicated by the form of the plant. The red sap of the bloodroot (Sanguinaria canadensis), for instance, was be...

plant pathology

(Encyclopedia)plant pathology: see diseases of plants. ...

dry rot

(Encyclopedia)dry rot, fungus disease that attacks both softwood and hardwood timber. Destruction of the cellulose causes discoloration and eventual crumbling of the wood. This frequently results in the collapse of...

Dutch elm disease

(Encyclopedia)Dutch elm disease: see diseases of plants; elm. ...

sudden oak death

(Encyclopedia)sudden oak death: see diseases of plants; water mold. ...

Bolley, Henry Luke

(Encyclopedia)Bolley, Henry Luke, 1865–1956, American plant pathologist, b. Dearborn co., Ind. He is noted for his work on organisms causing diseases of crop plants (including the discovery of the cause of potato...

blight

(Encyclopedia)blight, general term for any sudden and severe plant disease or for the agent that causes it. The term is now applied chiefly to diseases caused by bacteria (e.g., bean blights and fire blight of frui...

rust, in botany

(Encyclopedia)rust, in botany, name for various parasitic fungi of the order Uredinales and for the diseases of plants that they cause. Rusts form reddish patches of spores on the host plant. About 7,000 species ar...

rotation of crops

(Encyclopedia)rotation of crops, agricultural practice of varying the crops on a piece of land in a planned series, to save or increase the mineral or organic content of the soil, to increase crop yields, and to er...

National Institutes of Health

(Encyclopedia)National Institutes of Health (NIH), agency of the U.S. Public Health Service, with headquarters in Bethesda, Md. It was established initially in 1887 as a laboratory in the U.S. Marine Hospital on St...