Prior to 1972, the US maintained a stockpile of several biological agents capable of destroying the food and industrial crops of potential enemy countries.

Puccinia graminis tritici

Disease	Wheat stem rust
Pathology	Elongated ragged pustules on stem, leaf sheath, blade or chaff usually begin to appear in mid-June. Pustules rupture tissue, exposing powdery, brick red mass of summer spores. As wheat nears maturity, black pustules filled with black spores (teliospores) appear.
Prevention	Wheat varieties entirely immune to stem rust do not exist but varieties with various degrees of resistance do. Eradication of common barberry has been ongoing in the U.S. and is nearly complete. Fungicides are available for control of rust when needed

Wheat stem rust was part of the  US stockpile prior to 1972.

Puccinia graminis has many specialized varieties. P. graminis tritici attacks wheat and barley. P. graminis avenae occurs chiefly on oats. P. graminis secalis occurs chiefly on rye. Alternate host is common barberry, a tall erect woody shrub with bristle-toothed leaves.
Two articles on stem rusts are:

• Wheat Diseases in Missouri, published by University Extension, University of Missouri-Columbia
• Small grains/Stem rusts, published by the Division of Agriculture and Natural Resources, University of California

Puccinia graminis secalis

Disease	Rye stem rust
Pathology	Elongated ragged pustules on stem, leaf sheath, blade or chaff usually begin to appear in mid-June. Pustules rupture tissue, exposing powdery, brick red mass of summer spores. As wheat nears maturity, black pustules filled with black spores (teliospores) appear
Prevention	Use of resistant cultivars

Rye stem rust was part of the  US stockpile prior to 1972.

Puccinia graminis has many specialized varieties. P. graminis tritici attacks wheat and barley. P. graminis avenae occurs chiefly on oats. P. graminis secalis occurs chiefly on rye. Alternate host is common barberry, a tall erect woody shrub with bristle-toothed leaves. Two articles on stem rusts are:

• Wheat Diseases in Missouri, published by University Extension, University of Missouri-Columbia
• Small grains/Stem rusts, published by the Division of Agriculture and Natural Resources, University of California

Pyricularia grisea

Disease	Rice blast
Pathology	Very early off-white to gray-green spots of the leaves which rapidly enlarge and turn gray or gray-white in the center with a brown to reddish brown border. About a week after infection, the fungus sporulates within the lesion producing a dark, gray powdery appearance. At heading, blast kills the entire panicle before grain fill is complete.
Prevention	Resistant varieties are readily available, e.g., Katy, Kaybonnet, and Drew. Blast damage can be prevented or greatly reduced by proper irrigation. A flood depth of at least 2" and preferably 4" must be maintained from green ring through heading for this to be most effective.

Rice blast was part of the  US stockpile prior to 1972.

Management of Sheath Blight and Blast in Arkansas, by Rick Cartwright, Extension Plant Pathologist of the Cooperative Extension Service, Little Rock, and Fleet Lee, Professor of Plant Pathology at the Rice Research and Extension Center, Stuttgart, discusses rice blast and its management.