34 



ganate, lime water and air-slaked lime, but with the exception of a 

 slightly accelerated growth produced by the use of some of the above 

 named solutions he obtained entirely negative results. 



Hollrung reports some experiments with potash salts such as Kai- 

 nit, Carnallit, and Potassium chloride. The results obtained were 

 rather inconclusive but seem to show that potash salts while having a 

 palliative effect must not be considered as specifics for nematode 

 repression. 



Many European investigators have tried potash salts of various 

 kinds upon soil for the repression of nematodes. The literature 

 giving the results of their experiments seems to agree that more 

 beneficial eifects have been obtained from their use than any other. 

 On the other hand Dr. Max Hollrung' who has experimented exten- 

 sively for a number of years on the beet nematode and who has had 

 opportunity to try a great variety of methods and chemicals, claims 

 that potash salts in amounts in which they can be used as fertilizers 

 are not capable of destroying nematodes in the soil, and that the 

 beneficial effects of potash salts in such soils are due to other chemi- 

 cal and physical causes. Some sugar beet experimenters' have advo- 

 cated the use of good fertilizing together with the practice of plant- 

 ing early. They claim that by this method sugar beets can be 

 started at a time when they are likely to be less attacked by nema- 

 todes, as the plants can thrive even when it is too cold for the nema- 

 tode to be active and consequently less loss will be experienced by 

 their ravages. In regard to the efficiency of chemicals it must be 

 borne in mind that there are probably no instances where soil has 

 been completely rid of nematodes by this means, although in many 

 instances better crops have been produced after their application. 



Various methods of treating nematodes have been practiced for a 

 great many years in Europe, and a considerable amount of literature 

 has already made its appearance relating to this subject. Many 

 methods have been recommended and tried only to find that they 

 were not in every instance sure and practical, and these in turn have 

 been followed by others which have promised better results. 



One thing, however, appears to be certain, that many of these rem- 

 edies have only been given a superficial trial. Had the case been 

 otherwise, many of the remedies advocated would have become 



I. Zeitsch. landvv. Cent. Ver. Sachr., 1S92. No. 12. 



