20 



Dr. Augustus Voelcker, writing to Mr. Little in 1882, 

 remarks, after having given the analysis of a soil upon which 

 wheat was much mildewed : " This is a very instructive case, 

 for it confirms the frequent observations I have made in various 

 parts of England, that an excess of available nitrogenous food, 

 be it nitrate of soda, ammonia, salts, or organic matters which 

 are readily decomposed in the soil, appears to me to have a 

 decided tendency to cause mildew in wheat." Dr. Voelcker 

 goes on to show that wheat after a root-crop would be expected 

 to be far less mildewed than wheat after clover, which leaves 

 a large amount of nitrogenous food in the land. 



These are valuable contributions to the theoretical knowledge 

 of this subject, and are to some extent borne out by the various 

 inquiries that have been made respecting it, but it requires 

 careful experimentation and close observation to prove exactly 

 what is the effect of nitrogenous manures upon mildew, as well 

 as to demonstrate accurately what other conditions are favour- 

 able or unsuitable to its development and progress. Looking 

 at the four sets of inquiries that have been made since 1805, 

 and comparing them together, it is evident that the last does 

 not throw much more light on the question than the first, and 

 that if this question is to be solved satisfactorily it must be 

 relegated to trained observers. 



MILDEW IN FOREIGN COUNTRIES. 



Mildew, or rust, as it is generally termed abroad, is exciting 

 as much interest in other countries as in Great Britain. In the 

 United States, mildew, or rust, is a frequent trouble to wheat- 

 growers, occasionally causing much injury,* and is fitful and 

 uncertain in its visitation. In the United States, as in England, 

 and probably in all wheat-growing countries, there are other 

 kinds of mildew, or rust, than that due to Puccinia graminis, 

 which affect wheat crops, though they are not generally 

 differentiated by agriculturists. For example, in Great 

 Britain the fungus Cladosporium herbarum in some dis- 

 tricts did as much harm as Puccinia graminis in 1892, and 

 possibly in previous years. Rust is the common term employed 

 in the United States for affections of this nature as distinguished, 

 however, from smut, Ustilago segetum, and in Australasia rust is 

 generally used to designate the effects of Puccinia graminis and 

 other fungi of similar characteristics. In Germany the attack 

 of Puccinia graminis is styled rust, Getreide-rost, 



Great interest in the question of rust is being taken in the 

 United States at this time. The Massachusetts Experiment 



In the Bulletin cf the Agricultural Experiment Station of Indiana, 

 U.S., it is stated that rust is often credited with damage equal to 50 per 

 cent, of the normal crop, and it is estimated that the annual average loss 

 from thjs cause represents a sum of 820,000^, 



