STEM EELWORMS. 19 



tliem and reducing them to a wet disorganised pulp." Other details, 

 as well as observations of another fungoid attack [Peronospora trifolii), 

 are given ; but I quote the description of the method of destruction of 

 leafage by the widely spread 8. tiifuliorum as being completely different 

 from the characteristically deformed growth of buds and shoots, which 

 unfortunately we have had only too much opportunity of knowing for 

 some years back as the effect of the infestation of Tylenchus devastatrix, 

 or Stem Eelworm. 



I also have much pleasure in adding a few lines I was favoured with 

 by Dr. J, Eitzema Bos, Director of the Phyto-pathological Laboratory 

 at Amsterdam, relatively to information he had given me when I had 

 the advantage of some conversation with him here early in the year : — 

 " I said that in Holland I often found a very dangerous Clover-sickness 

 caused by the fungus Sclerotinia trifuliorum [ — Peziza cihorioides). This 

 Clover- sickness is in Holland much more common than the Clover- 

 sickness caused by Tylenchus devastatrix. It sometimes occurs that 

 both diseases attack the same plant. T. devastatrix causes an ab- 

 normal growth, and can cause at length the death of the Clover plant ; 

 Sclerotinia trifuliorum causes the death of the plant after some days." — 

 (J. E. B.) 



In by far the greatest number of samples of injured Clover sent to 

 myself, mischief was demonstrably to be attributed to Clover Stem- 

 sickness, caused by Tylenchus devastatrix, or Stem Eelworm, as shown 

 by the peculiar form of diseased growth to which this infestation gives 

 rise, and also by the presence of Eelworms in the diseased shoots and 

 buds. 



The Stem Eelworm is a minute, transparent, white " threadworm " ; 

 when full-grown, only about oue-twenty-fifth of an inch (about half a 

 line) in length, and its greatest breadth is about one-thirtieth of its 

 length. The very small white worms often seen at the roots of plants, 

 which may be worm-like fly larvro, or very young "earthworms," or 

 nearly allied to them, are sometimes mistaken for Tylenchi; but these 

 may be a quarter of an inch or more in length, and the fact that they 

 can be observed without difficulty by the naked eye shows at once that 

 they are not " Stem Eelworms." 



The figure at p. 17 shows the general appearance of Tylenchus 

 devastatrix when much magnified, and the right-hand figure shows a 

 special characteristic of the Tylenchi, of presence in the cesophayus (or 

 "gullet"), by which they suck in their food, of a sharp needle-like 

 process, called the spear, placed on a bulb-like base, which, when 

 much more magnified, will be found to be trilobed. There is also iu 

 the case of this species a characteristic distinction in the structure 

 of the male; but as the greatest length of these wormlets is only 

 about one-twenty-fifth of an inch, these distinctions, which are only 



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