458 STATE BOARD OF AGRICULTURE. 



year, clover and timothy meadow; second year, corn; third year, oats 

 seeded to clover and timothy; fourth year, clover and timothy; fifth 

 year, timothy and clover. 



5. Six year rotation including beans or beets: first year, clover; 

 second year, corn, beets or beans; third year, oats; fourth year, clover; 

 fifth year, beans, beets or corn, and sixth year, wheat seeded with clover. 



6. Alfalfa 3 to 5 years, corn, corn, barley or oats seeded. 

 Rotation 1, 2, and 3 are most frequent in southern and central Michi- 

 gan. 



In bean and beet regions 4 and 5 are often followed. Rotation No. 5 

 is particularly effective in the upkeep of organic matter since a clover 

 crop occurs every third year. 



An alfalfa sod furnishes excellent condition for corn, and owing to 

 the success with which this crop is being seeded, the more general use 

 of rotations including alfalfa is highly desired. 



CORN SMUT 



In view of the prevalence of corn smut and the importance of con- 

 trolling this disease, the following discussion has been prepared by Dr. 

 G. H. Coons, Plant Pathologist of the Michigan Experiment Station: 



IS BEST CONTROLLED BY ROTATION 



Every year at harvest time, inquiries come as to the cause and con- 

 trol of corn smut. This is a fungous disease related to, but entirely dis- 

 tinct from the smut diseases known for other crop plants, — ^wheat, oats, 

 and barley. The smut affects the corn at almost any growing part, the 

 stem, the leaf, the ear, the husk, the silk or the tassel, producing a swell- 

 ing which is at first white then greenish black. The attack of corn smut 

 may come at any time of the season when corn is growing, the newly 

 formed tender parts being most subject to it. 



Typically the corn smut fungus lives over winter in the old stalks in 

 the field. These live, infectious spores in the spring are blown by the 

 wind to the young corn. A close examination of corn about a foot 

 high will reveal a plant here and there with whitish over-growths, — the 

 so-called smut boils. Only a few of these are formed, but they mature 

 their spores and furnish the source of the later infections. Over and 

 over again the story is repeated until the corn shows in the fall a liberal 

 amount of this wasting disease. 



The control measures for corn smut depend upon the nature of the 

 smut's life history. Since infection takes place throughout the season, 

 this disease cannot be prevented as is oat smut or wheat stinking smut, 

 by seed treatment. In short, any recommendation to dip seed for control 

 of corn smut is unwarranted. 



Since the source of smut in early summer is largely the old smutted 

 stalks of last year's crop, the planting of corn to follow corn augments 

 most seriously the amount of smut infection. Experience in Michigan 

 with field corn has indicated that with the ordinary season rotation is 



