102 TOMATO, 



those in Plate IV., Figs. 9, 17, 18, 21, of Atkinson's 'Report,' and 

 ova."— (J. E. B.) 



The Cucumber infestation which we have here, was thus found to 

 correspond both in the kind of Eelworms, and in the galls to whicli 

 they gave rise, to that of the H. radicicola, and its effects, already 

 studied on Tomato roots; and it was of some interest to contrast the 

 condition of the Eelworms, in the one case (in tlie spring) being to a 

 great extent growing up to maturity ; and in the other, in the old 

 matured galls towards the close of the year being so much more 

 observably represented by adult specimens, especially the gourd- 

 shaped females with their larval or egg contents. 



The galls on the various kinds of plant roots on which I have seen 

 them, that is, on roots of Tomato, Cucumber, and on roots of one young 

 Lettuce plant sent me for examination from Belgium, were small 

 knobs, or irregularly shaped lumps, varying in size from an eighth of 

 an inch or less in diameter to (in the case of the Tomato) fleshy lumps 

 a quarter of an inch to half an inch or more in width, and much more 

 in length ; even to as much as one, two, or over three inches of 

 irregular swollen gall growth along the root fibres where the galls 

 were confluent. 



The method of infestation may be in various ways. The Eelworms 

 may escape into the earth through cracks in the gall, or may make 

 their way out by use of their mouth-spear; or again, as I found in the 

 case of the Tomato galls sent me late in the year, may be freed in 

 myriads by the peeling off of the outer part of the coat of the " root- 

 knot." But in whatever way the Nematode may have conveyed itself 

 into the ground, the next step, that of its entrance into the plant to be 

 attacked, is thus described by Prof. Atkinson, — p. 16 of pamphlet 

 cited. "•'= "Having escaped from its confinement," . . . " it imme- 

 diately selects another part of the root, or a fresh young rootlet, for 

 . attack, and places itself in position for the siege. Bringing into play 

 its exsertile ram, it forcibly gains entrance to the healthy tissues of the 

 root," &c. There the parasitic action sets up the diseased swelled 

 growths, which, as we now know in England to our sorrow and loss, 

 carry off the plant juices to supply the growth of these vegetable 

 tumours, and ruin the hopes of the expected crop. 



A further word should be added as to the need of great care in all 

 investigations as to the nature of the tenants of the root-knots ; those 

 who are not well accustomed to the identification of Nematodes, can- 

 not be too strongly warned against the error of mistaking these Hctc- 

 rodera radicicola, or Boot knot Eelworms, for the Tylenchus devastatrix, 

 or Stem Eelworm. The exceedingly minute resemblance of the first- 



* See footnote, p. 100. 



