220 CORN 



are the only results of infection of the more mature stalk. Leaf 

 sheaths and even the developing ear are often infected, showing a 

 jelly-like deposition. The ear occasionally becomes a mass of rotten 

 slime. The. presence of the disease is noted to a greater extent some 

 years than others. The prevention has not been carefully studied as 

 yet. Destroying affected parts is the only sure way of absolute eradi- 

 cation. This disease is sometimes known as 'corn blight.' " 



CORN WILT. F. C. Stewart, of the Geneva Experiment Station, 

 New York, has identified another bacterial disease of corn. His 

 observations are that the plants wilt and dry up, but do not roll 

 up as in the case of lack of moisture. Young plants die in a few days, 

 but the older plants live for some time. The disease has been known 

 to destroy entire fields. Dr. Erwin F. Smith has investigated this 

 disease and named the organism Pseudomonas Stewartii. 



LEAF BLIGHT. The infection of the leaves of corn with the 

 leaf blight fungus is not discernible without the use of the magni- 

 fying glass. The almost round brownish spots are usually devoid of 

 life. As yet the frequency of affected plants is so limited that no con- 

 cern is felt regarding the economic importance of this fungous growth. 



MAIZE RUST (Puccmia sorghi Sch-w). "Maize rust is found 

 wherever maize is grown, but principally in regions of considerable 

 rainfall. The rust does not differ materially in appearance from rusts 

 of other grasses, particularly the Puccinia graminis of wheat and 

 oats. The surface of the affected leaf and sheath displays small 

 oblong or elliptical spots, which contain reddish brown spores. Kel- 

 lerman has shown that only the iiredo and teleuto stages may be 

 included in the life cycle, although Arthur has identified the aecidial 

 stage on Oxalis. It passes the winter in the teleuto stage. Though 

 fungicides are effective, the rust is not of enough economic impor- 

 tance to warrant treatment. Pammel reports decreased yields of 

 sweet maize due to the rust. The rust also occurs on sorghum and 

 teosinte."* 



CORN STALK DISEASE.* This disease is characterized by the 

 falling of the corn or the stalks are broken close to the joints. In 

 many cases the corn is broken off just .below the joint or just above. 

 The pith is destroyed, brownish or in some cases reddish in color. 

 The fibers are soft and easily broken off. The small dwarf shoots in 

 the axis of the leaves are often decomposed. On the surface of the 

 stalk and in the nodes there is often an abundance of the mould.** 



*Iowa Circular No, 21. 

 **This was determined as a species of Fusarium. Other species of this genus cause wheat scab 

 or blight, flax wilt, cucumber wilt, etc. 



