264 Blacl Currant Eelworm 



year a mat of stolons had grown round the parent plants. These 

 were in all respects normal products and they proved to be free from 

 worm when examined microscopically. The parent plants also were 

 normal and were^ when lifted and subjected to like treatment, found 

 to be free from infection. 



There is in this experiment carried out under orchard conditions 

 confirmatory evidence that the worm causing bud rot in black currant 

 is not identical with that causing Cauliflower disease in strawberry. 



Finally, inoculation experiments on various seedlings including 

 clover, oats, onions and wheat were also undertaken in the laboratory 

 under those conditions found to favour distribution. Soil inoculation 

 was employed throughout and the length of the inoculation period 

 was that of previous experiments. 



The results obtained were negative in so far that the typical symp- 

 toms exhibited by such plants when attacked by eelworm did not 

 appear. There were however present in many of the seedlings localized 

 discoloured areas in the leaf tissue on which small numbers of worms 

 were found leading an ectoparasitic existence. They proved to be 

 absent from the internal tissues of leaf, root, and stem, when examined 

 microscopically. 



Collectively the experimental data taken from the infection of 

 probable host plants appear to shew that under abnormal conditions 

 a weakly facultative ectoparasitic existence can be led. 



This evidence is not however confirmed by observation and experi- 

 mental work carried out under normal conditions in the field. 



Observations on the Desiccation of the Worm. 



In the life history of the group Anguillulidae the desiccation of 

 the living organism occurs at times when unfavourable conditions 

 for distribution or for obtaining food persist. Should this state, in 

 which active life is suspended and no food is partaken of, be maintained 

 for months, or in some cases for years together, the worms can, on 

 favourable conditions reasserting themselves, resume their active state. 

 Thus in the case of Tylenchus tritici^ the worm has been known to 

 return to a motile existence after a period of 27 years of desiccation. 



Seeing that from a practical point of view this habit is one of 

 importance, the following observations were made on the habits of 

 the black currant worm after certain periods of desiccation. 



1 Bastian, H. C, "Monograph on the Anguillulidae," Trans. Linn. Soc. xxv, 1806 (read 

 1864), p. 86; 



