178 Annuokl lU/ort for 1889 of the Consulting Entomologist. 
Clover " Stem-Sickness," 
caused by Tylenchus devastatrix, Kuhn (a species of very minute 
white eelworm), within the plant. 
During the latter part of the winter of 18S8, and up to May 
in 1889, I received many communications regarding serious failure 
of clover crops, with specimens of various kinds of insects, worms, 
or other supposed causes of the injury, sent accompanying. In all 
cases, however, in which sufficient material was sent to me for 
complete investigation (that is to say, where plenty of specimens of 
the whole plants were forwarded), I have no hesitation in saying 
that the disease was due to the presence of the Tylenchus devastatrix, 
Kuhn, the same kind of minute nematode, or eelworm, which causes 
the disease known as " tulip-root " in oat plants, and which attacks 
many other grasses and wild i^lants, and some other regular crops. 
This attack may be known by the presence of the minute eelworins, 
often in great numbers, together with their eggs, in the infested 
buds and stems, and also (and more conveniently for general pur- 
poses) by the infested shoots having usually a more or less deformed 
growth. 
In some cases the buds were inflated, and the brandies shorter 
and thicker than in the regular clover growth, and also, especially 
from one locality, the abnormal buds, or shoots, checked by the 
eelworm presence, though now decayed, showed a kind of bulb shape, 
like a knot of large leaf- scales ; and one most especially injured shoot 
had about six of these shortened shoots placed almost close together 
on the central stem. 
By these growths the attack may be distinguished, when it 
is severe, as easily as the bulb-like Tylenchus attack to oat plants 
known as " tulip-root " may be distinguished by the somewhat tulip- 
bulb-formed swelling of the base of the stem, with the fringe of 
thin, pale, doubled-up shoots growing around. Both attacks are 
caused by presence of the Tylenchus devastatrix, or " stem-eelwonn," 
as has been' proved by infesting one kind of plant from the other. 
The " stem-eelworms " may be found in all stages, and male 
and female as well as young and eggs, in the infested buds and 
stems. » 
As it was eminently desirable that we should know the species 
beyond possibility of mistake, I submitted specimens from both 
Woburn and Rothainsted for technical examination by Dr. J. 
Eitzema Bos, Professor at the State Agricultural College, Wagon- 
ingen, Netherlands, as being one of the highest authorities on the 
subject, and these plants he found to be diseased in the same 
manner that is, to have the same deformed growth as clover in- 
fested by T. devastatrix, which he had studied in the field in the 
Netherlands, and in the swollen buds and in the shoots he found this 
Tylenchus in large numbers, and he also found the eggs. 
In the dying parts of the plant other nematodes were present 
in small numbers of different kinds, as Cephalobus, Ixhalditis, and 
Diphxjaster, but these are immaterial to the present inquiry. 
