52 EELWORMS. 



forms of attack, unfortunately never failing to be reported yearly, are 

 those causing the diseased growths known as Tulip-root, or as Segging 

 in Oat-plants, and Stem-sickness in Clover. 



During the past season of 1894, I have had various applications 

 regarding the above infestations, and in the case of Tulip-root, or 

 Segging, some exceedingly well-marked specimens were sent me ; but 

 as quite full descriptions of these attacks, with well-proved means of 

 prevention and remedy, have previously been given in these Reports, 

 I have only entered on the subject again as possibly useful in con- 

 nection with a very curious observation made last summer at one 

 locality in Kent of the presence of this Eelworm (or as far as appears 

 at present this Eelworm), being found as well as the Beet Eelworm, 

 Heterodera schachtii, at Hop-roots in coincidence with the diseased 

 growth of top and leafage known as being " nettle-headed." 



That the H. schachtii, the so-called Beet Eelworm, should be found 

 at Hop-roots is not surprising, for it infests various plants, and from 

 observations made in Holland during the last few years evidently it 

 is either spreading more widely, or its presence is more observed. But 

 the presence of the Tylenchus devastatrix in the root or root-like 

 underground part of the Hops is a very remarkable and curious cir- 

 cumstance, as previously it does not appear to have been observed 

 save in stems or portion of stem-growth. 



The first notice which I observed of this investigation was in a 

 paragraph (subjoined in the accompanying note) which was given in 

 the number of ' The London Corn Circular ' for September 3rd (1894), 

 as a quotation from ' Natural Science ' for that month. It is perhaps 

 desirable to give this verbatim and (// e.vtenso, as showing the locality 

 and basis of the observations.* 



* " Hop Disease in Kent. — We learn from Professor J. Percival, of the South- 

 Eastern Agricultural College, Wye, Kent, that he is at present engaged investigating 

 the disease which causes Hops to become what is known as " nettle-headed." The 

 disease is met with in many districts in the county, and has rapidly increased 

 during the last few years — in some cases leading to a complete destruction of con- 

 siderable areas of Hop-gardens. The early delicate varieties are most attacked, 

 and especially those which have been growing for a considerable time. It is rarely 

 until five years after planting that the disease is seen, and usually not until a much 

 later period. In a typically affected plant the leaves are smaller than is generally 

 the case, and are transformed in such a manner as to become strikingly like those 

 of the Stmging-nettle. The edges of the leaves turn upwards ; the fibro-vascular 

 bundles in them are increased slightly in thickness, and stand out well from the 

 under surface of the leaf. , Closer examination shows destruction of the soft tissue 

 in immediate contact with the fibro-vascular bundles ; the parts become thin and 

 yellow, and much resemble the thin spots produced by the action of sulphur dioxide 

 gas on the leaf. The internodes of the plant are short and the main stem and 

 branches taper more rapidly than in healthy plants. In practically all cases the 

 bine or stem, after climbing a short distance up the pole, loses its power of twining 



