l36 TOMATO. 



instead of lessening. In examination of the plants, and also in 

 clearing them, it should be most carefully seen to that they are not 

 raised by being drawn out of the soil. They should be raised so that the 

 earth comes with them, otherwise the little knobs on the root are just 

 as likely as not, from the obstruction they cause in drawing, to cause 

 the young rootlets to break off, and thus the examiner be unaware of 

 the presence of galls. And in clearing the "trap plant," neglect of 

 this precaution would leave the ground full of infested " knots." A 

 glance over the list of common plants subject to infestation would 

 suggest what might be serviceable ; very possibly Kadishes might be 

 of use, but one plant particularly recommended for the purpose is 

 Lettuce, sometimes known as '• Salad." 



In my recent correspondence with Dr. Ritzema Bos on this subject, 

 he favoured me with the following remark, embodying the opinion of 

 the well-known observer of these Eelworms, Herr Frank, on this 

 subject: — " Frank says that Lactiica saliva (the common Lettuce) can 

 be used with success as a trap plant ; but as the larvffi leave the galls 

 principally in the winter and the spring, the Lactuca should be sown 

 as early as possible in the spring or the winter." — (J. R. B., Dec. 31st, 

 1892). 



As yet we do not know to what extent the Heterodera radicicola is 

 present here, but with the knowledge of the characteristics of the 

 attack, it is very likely more information may be received on this head, 

 as being a trouble to growers of garden crops under glass, as Cucum- 

 bers, Tomatoes, &c. Whether the pest is present in out-of-door crops 

 here, we are (as far as I am aware) without any reliable proof at 

 present. 



In 1886, a paper was published in the * Gardeners' Chronicle ' 

 (p. 172, vol. xxvi.), in which a very good account was given of the 

 characteristics of the Oat-plant attack, which has since been most 

 minutely observed, and which is well known under the name of Tulip- 

 root, or Segging. In this the writer guardedly suggests that this 

 disease is caused by the H. radicicola ; he does not say that it is so, but 

 merely, "I take the worm to be Heterodera radicicola'' ', and after 

 carefully studying a copy made for me of the paper, and of the figures 

 of the Eelworms accompanying (the original being out of print), I do 

 not find any mention of the pear- or gourd-shaped females which are 

 an essential condition of the Heterodera racfe'ctcote now under considera- 

 tion. The long thread-like forms of all the Eelworms figured quite 

 correspond with those of the Tylenclms devastatrix, which has now been 

 shown by successive years of investigation to be the cause of Tulip-root.* 



* See also note, p. 6, of ' L'Anguillule de la Tige {Tylenchus devastatrix, Kuhn),' 

 par Dr. J. Bitzema Bos; 'Annotations Deuxieme Serie,' Haarlem, 1891, in which 

 the above points are entered on at length. 



