230 ROOT-KNOT EELWORM. 



the body of the cyst breaks up into an amorphic gelatinous 

 mass, in which the young larvae and eggs are found floating 

 within the cyst cavity. Length of Hfe cycle, one month." — 

 (G. F. A.) 



Method of spread of infestation. — The Eelworms may be 

 found in all conditions in the root-galls. In the case of some 

 specimens of galls from Cucumber roots which I forwarded to 

 Dr. J. Kitzema Bos, the Director of the Phytopathological 

 Laboratory at Amsterdam, for the benefit of his skilled 

 opinion, he was good enough to tell me that he found the 

 male and female and different stages of the larvpe of Iletero- 

 dera radicicola present, " like those in plate iv., figs. 9, 17, 

 18, 21, of Atkinson's Report, and ova.'" 



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 (see p. 222), may he freed: in myriads by the 

 peeling ofi' of the outer part of the coat of the ''root-knot." 

 But in whatever way the Nematode may have conveyed itself 

 ijito 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 confine- 

 ment, ... it immediately 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 [mouth- 

 spear], it forcibly gains entrance to the healthy tissues of the 

 root," &c. 



In regard to the important point of attack to rootlets taking 

 place from "Root-knot" Eelworms wandering free in the 

 soil, it is thus recorded from his own observations by Dr. J. 

 C. Neal t : — "I have found mature worms, males and non- 

 pregnant females, in rootlets but a few days old, and under 

 circumstances which involved the necessity of invasion from 

 without the root." These Angmlluke, Dr. Neal notes, were 

 small enough to enter the stomata of epidermal tissues, and 

 he thinks it " not unreasonable to infer that in this manner 

 they obtain entrance in young rootlets." Once within they 

 can make their way about in the tissues of the root, and the 

 result of their presence is the unnatural development of cells, 

 producing the irregular growth known as the gall or root-knot. 



Prevention and Remedies. — These at present appear, so 

 far as I am aware, as a certainty, and at a paying (or indeed 



* See footnote, p. 222. 



t See ' The Root-knot Disease of the Peach, Orange, and other jilants, in 

 Florida,' by J. C. Neal, Ph.D., M.D., p. 12. Washington : Government Printing 

 Office. 1889. 



