52, CORN AND GRASS. 
such rotation as will not give a crop liable to be attacked in immediate 
succession to one which is known to have been infested by Kelworms. 
Oats and Clover are the crops that suffer most severely with us; but 
Wheat and likewise Beans are liable to attack, and also Onions. 
When a field, as of Oats for instance, is infested, it is very difficult 
to clear the land, and also to prevent the attack being carried about in 
manure, as a portion of the Helworms, very possibly most of them, 
customarily leave the dying and drying plants and go into the land, 
and some are carried within the cut crop, and being mixed up in the 
straw with farmyard manure, are presently carried out again, and 
spread quite uninjured on clean fields, or perhaps on the very field 
from which they came. 
To clear the land, very deep ploughing is needed, or rather 
ploughing with a skim-coulter attached, so that the Kelworms may 
be well turned down and covered over with a depth of soil through 
which they cannot force their exceedingly minute bodies. In garden 
eround, or for treatment of patches which often make centres of 
infestation in fields, ‘ trenching’”’ acts well,—that is, digging to two 
spades depth, and burying the upper layer wholly beneath what was 
the lower one of uninfested soil. But common digging, or double 
digging, and also common ploughing, which only break up and scatter 
the soil, and do not bury the surface soil down with the contained 
Helworms, do little good. 
It should also be borne in mind that the Kelworms can be conveyed 
in infested earth. They are thus conveyed on wheels of carts, in 
earth clinging to farm implements and to garden tools, and even on 
the boots of farm labourers, and from their power of propagation a 
small beginning makes much trouble. 
An enormous amount has been written on Anguillulide on the 
Continent, chief amongst which, for most serviceable instruction, as 
well as the highest scientific information regarding attacks to various 
kinds of plants and field crops, is the work by Dr. J. Ritzema Bos, 
Director of the Phyto-Pathological Laboratory at Amsterdam, men- 
tioned below * ; also in many of my Annual Reports I have given the 
results of careful observation by qualified agriculturists of treatment 
found to answer in this country, to which I refer my readers for fuller 
details than can be given conveniently in one Report. 
* «L’Anguillule de la Tige (Tylenchus devastatrix, Kuhn),’ par Dr. J. Ritzema 
Bos, Prof. 4 ’Ins. Ag. de ’Etat & Wageningen, part i. 1888, ii. 1889; and ‘ Anno- 
tations,’ 1891, 4to, Haarlem. 
