72 HATCH EXPERIMENT STATION. [Jan. 



severely affected than those located in dry places. The prin- 

 cipal feature which we wish to emphasize in connection with 

 these experiments is that the summer stage of the asparagus 

 rust is due to a weakened condition of those plants growing 

 on dry soil during seasons of extreme drought. In other 

 words, the plants suffer for water ; and, since this is the case, 

 the rational method of prevention must take the amount of 

 soil moisture into consideration. It will not be out of place 

 here to reflect upon the present status of the rust problem, 

 and consider the methods which should be employed in our 

 endeavors to control it. 



The practice of spraying, it would seem, is not likely to 

 give promise of any remarkable results, because the asparagus 

 plants offer diflSeulties in this respect, and all of the rusts 

 are hard to control, Stewart found, in his experiments on 

 spraying for the carnation rust, which attacks a host largely 

 confined to greenhouses and therefore much better under con- 

 trol, that the best results obtained by spraying were not very 

 promising. Then, again, it is possible that the asparagus 

 rust mycelium may be confined to the plant throughout the 

 year, in which case the value of spraying would be practically 

 useless. We have observed a fungous mycelium in the roots 

 and stems of the asparagus plants below the ground long 

 before any occurrence of the rust showed upon the aerial 

 stems ; but whether the mycelium was identical with that of 

 the rust, or of other parasitic fungi frequently found upon 

 the asparagus, we were not able to ascertain. We must 

 therefore turn our attention to other methods of control, — 

 to methods which will enable us to keep the plants under 

 more normal conditions during seasons of drought. These 

 methods will consist, first, of securing the most vigorous 

 plants, — a feature which is dependent upon cultivation and 

 the proper kinds and amounts of plant food with which the 

 plants are supplied. There is considerable difference in the 

 plants of various growers in this respect ; the most vigorous 

 and largest plants which we have observed were situated in 

 a dry region, subject to uredo infection, but they have never 

 suffered from the rust till this season. The amount of rain- 

 fall between April 1 and September 1 of this year has been 

 the lowest for many years, and many beds have shown the 

 summer stage for the first time this year. It is interesting 



