NOTES OP OBSERVATIONS 
OF 
INJURIOUS INSECTS 
AND 
COMMON CROP PESTS 
Dubing 1887. 
CLOVER. 
Clover-sickness caused by Eelworms. Tylenchns devastatrix, 
Kuhn. 
During the investigations in 1886 as to the cause of the diseased 
growth known as “Tulip-root” in Oats, there seemed reason for 
supposing that the same kind of very minute Eelworms which are the 
cause of this Oat disease were also the cause of the disease known as 
“ Clover-sickness.” This kind of Eelworm (scientifically, the Tylenchus 
devastatrix ) attacks a very large number of different kinds of plants, 
including various kinds of bulbs and grasses, and common meadow 
and field plants, besides various kinds of corn and cultivated crops ; 
and, from the widespread ravages, the special name has been changed 
in the last few years from the Tylenchus dipsaci, or “ Teazle Tylenchus 
to the T. devastatrix , alluding to the “ devastations ” it sometimes 
gives rise to. 
These Tylenchi are excessively minute Eelworms (of the same 
nature, though not the same habits, as Paste Eelworms), but so small 
that they cannot be distinguished at all without strong magnifiers, 
about the 24th of an inch long, and they are to be found as male, 
female, undeveloped young, and eggs, sometimes in vast numbers, in 
the attacked plants. 
As disease in Clover arises from many different causes, as frost, 
fungi, &c., it is right to specify that the following observations about 
Tylenchus presence are only meant to refer to cases of the disease 
B 
