62 MASSACHUSETTS HORTICULTURAL SOCIETY. 



alkalinity. If this opinion is sustained the relation of the fungus to 

 the host can only be explained through increased sensitiveness on 

 the part of the host under alkaline conditions. 



Soil liming is distinctively beneficial in preventing the attacks of 

 Plasmodiophora, the fungus which produces the club rot of cabbage 

 and turnips. It is possible that the lime is directly injurious to the 

 fungus, but so far as I am aware no studies have been made to 

 determine whether it is directly injurious to the fungus or directly 

 beneficial to the host plant. It is certain that the cabbage plant is 

 partial to an alkaline condition of the soil, and experiments in 

 Japan have demonstrated that this plant prefers a content of cal- 

 cium which shall be relatively great in comparison with that of 

 certain other mineral nutrients. 



Nutrition. 



It is extremely difficult to interpret the effect of nutrition upon re- 

 sistance or susceptibility to fungous diseases on account of the 

 great complexity of the problem. In the experimental plots of the 

 Rothamsted Experiment Station it has, however, been very clearly 

 shown that one-sided nutrition, particularly over-fertilization with 

 nitrogen, unaccompanied by the other essential fertilizers, results 

 in the appearance of many fungous diseases upon the plots so 

 treated, which diseases are practically absent from the plots ferti- 

 lized with complete manures. The application of nitrogen in un- 

 balanced quantity to crops has long -been considered as the cause of 

 a production of weed at the expense of grain or fruiting, and a few 

 experiments reported by Ward on the grasses indicate that potas- 

 sium or phosphates, when afforded the plant only in minimum 

 quantity, cause not only a starvation of the host, but of the fungus 

 as well; and he believes that any "hindrance" to free nutrition, 

 assimilation, transpiration, etc., also act detrimentally to the well 

 being of the mycelium. 



In connection with the phenomenon of nutrition, it is perhaps 

 necessary to say a word at least concerning the often discussed 

 possibility of feeding the host plant toxic solutions in order to 

 prevent fungous diseases, or the possibility of injecting such solu- 



