KJ2 FIELD CHOPS 



everyone, on account of the abundance of its brick-red spores 

 on the leaves and stems at harvest time in years favorable 

 to its development. The stem rust of oats is very similar 

 to the stem rust of wheat, appearing as black spots or blotches 

 on the leaves and stems shortly before the grain ripens. The 

 stem rust is rather less common than the leaf rust, but when 

 it occurs it injures the crop more seriously. Both these rusts 

 are very common in the South, appearing practically every 

 year. In the Northern states, where climatic conditions are 

 more favorable to the growth of oats, rust injury is decidedly 

 less frequent. It is most likely to occur in wet seasons, 

 when the growth of the crop is rank. Oats on rich, wet land 

 are particularly hkel}' to be infected. The conditions favor- 

 able to the development of this disease are soft, rank growth, 

 dam_p, cloudy weather or heavy dews; and land which is par- 

 ticularly retentive of moisture. No effective remedies have 

 yet been discovered. Some varieties or strains of oats appear 

 to be more rust-resistant than others, and plant breeders are 

 attempting to develop this quality to a still greater degree. 

 As conditions favorable to rust are most likely to occur late 

 in the growing season, earty varieties often escape rust at- 

 tacks which do serious damage to late oats. The best pre- 

 ventive measure is to sow early varieties on well-drained land 

 which is not too rich, thus avoiding as much as possible the 

 danger of too rank growth and the moist conditions so con- 

 ducive to the development of rust. 



Oat smut is also of tw^o kinds, the loose and the covered. 

 These smuts differ but little in appearance, and their life 

 histories are practically the same. The spore enters the 

 growing point of the plant about the time of germination, 

 and the slender threads of the smut fungus develop in the 

 tissues of the plant along with its natural growth. The 

 smut reaches its mature form in masses of black, powdery 

 dust, or spores, which replace part or all of the oat head. In 

 ioose smut the chaff as well as the grain itself is replaced by 



