9 6 



OATS 



volunteer crop which grows in the fall from the oats shelled 

 by harvesting is usually more or less affected and these 

 spores affect the following crop, hence the necessity of 

 rotation. Oats that are immune from rust can be bred 



for certain localities, but if carried 



a distance and put 

 under a different 

 environment, they 

 seem to lose this im- 

 munity and become 

 as susceptible as are 

 other varieties. 



Oat Smut. The 

 oat smut is a dis- 

 ease that is carried 

 over from year to 

 year through the 

 infected seed, and 

 continues to in- 

 crease until over 

 half of the crop 

 becomes contami- 

 nated. The plant 

 becomes infected 

 through spores 

 which find lodgment 

 beneath the oat hull 

 during the flowering period, and remain there until the 

 oat is sown and starts to sprout. The spore then sends 

 up tiny threads through the several culms of the plant 

 and blasts the heads by causing a mass of smutty spores 

 to destroy practically all oats on the affected plants. 

 These spores are wafted off when the oats are in 



Fig. 50. Two heads of oats grown from the same lot 

 . of seed. The head on the right was grown from 

 seed that was treated to prevent smut ; the other 

 was grown from untreated seed. 



