FUNGUS DISEASES 1 43 



words, burn the plants as soon as they become brown 

 and lifeless, for any delay means the breaking up of 

 the brittle, rusty plants, and a heavy sowing of the 

 spores upon the ground. If the fire could go over the 

 whole field of standing brush, that would be the most 

 effective destruction. At best, with these precautions, 

 many of the spores will get scattered upon the soil, 

 and it would be well to sprinkle a thin coat of lime 

 upon the ground and leave it there during the winter. 

 If this could be followed by a turning under of the 

 surface soil in the spring, it would bury the spores 

 that might still be living, so that thej^ would be out of 

 reach. 



Cultivation and irrigaiion. — It has been observed 

 that the injury to asparagus plants, as a result of rust, 

 has been confined to dry soils, although there are 

 places where beds in close proximity showed remark- 

 able differences as to infection; and that robust and 

 vigorous plants, even where cultivated on apparently 

 dry soil, are capable of resisting the summer or inju- 

 rious stage of the rust. 



In view of all the experiments so far made, and the 

 experiences of pradlical asparagus growers. Stone and 

 Smith conclude that : ' ' The best means of controlling 

 the rust is by thorough cultivation in order to secure 

 vigorous plants, and in seasons of extreme dryness 

 plants growing on very dry soil with little water- 

 retaining properties should, if possible, receive irriga- 

 tion. ' ' 



From a knowledge of the occurrences of the rust 

 in Europe, and from observations made in Massachu- 

 setts, they are led to believe that the outbreak of the 



