FLORIDA STATE HORTICULTURAL SOCIETY. 
29 
Strange to say, the root-knot nematode is 
easily killed by drying out, although many 
of its close relatives are dried without 
injury, and can remain alive for years 
in that condition, reviving again upon 
being moistened up. Paradoxical as it 
may seem, moisture will also kill the root- 
knot nematode. It has often been found 
that wet lands are free from nematode 
injury while dryer lands adjacent suffered 
badly. In one case I learned of some 
very badly infected land flooded by a 
spring freshet for several days. Always 
thereafter it bore crops showing no sign 
of root-knot. In Java this method had 
also been tried and found to be successful. 
The land must be submerged at least five 
to eight days. 
Besides these direct means for freeing 
the soil of nematodes several indirect ones 
have been suggested, and it is by some 
of these that I believe our main salvation 
can be attained. The first to be mention¬ 
ed is the starvation method; i. e. growing 
nothing on the land that can serve as food 
for the nematodes until all has perished. 
How long this would require for the 
root-knot nematode has not been determ¬ 
ined ; for its close relative, the sugar-beet 
nematode, it is not under two years. To 
keep the land entirely fallow this length 
of time is, of course, not to be thought of, 
but the same results can be attained by 
cultivating only plants not attacked by 
root-knot even in the slightest degree. 
Hence comes the great importance of 
numerous experiments to determine which 
plants are and which are not susceptible. 
Of those which so far I have found to be 
free from root-knot, are crabgrass, the 
small grains, velvet bean, Florida beggar- 
weed and but few others. Such infor¬ 
mation bearing on the subject as I can 
obtain from you will be gratefully receiv¬ 
ed. In view of the facts known the prac¬ 
tise of many of allowing the land to grow 
up thickly to crabgrass in the summer, 
is one that ought to tend to keep the 
root-knot nematode in check. If that 
could be combined with the use of velvet 
bean for a season or two, or if small 
grains were sown as winter crops for 
two years followed in the summer by vel¬ 
vet beans it looks to me as if favorable 
results should be obtained. I have such 
experiments already under way. 
Another method of combating the pest, 
which promises very good results for cer¬ 
tain annual crops, is that of breeding up 
resistant races. Thus the Iron cowpea, if 
obtained pure, is not attacked by root- 
knot. Unfortunately, however, most of 
that obtainable in the markets or even 
some of that sent out from other sources, 
contained some admixture of other va¬ 
rieties vitiating the results. Mr. W. A. 
Orton has demonstrated that this quality 
of resistance is transmissable to crosses 
with other sorts. Doubtless some results 
of value can be obtained by selecting seed 
from plants least affected in a field known 
to be full of root-knot. Such plants, when 
in flower, should be crossed, if possible, 
with similar resistant plants in same field. 
In this way a nematode resistant sugar- 
beet has been obtained. 
The influence of increased amounts of 
certain elements of fertilizers on the 
amount of injury caused by root-knot has 
received, I find, practically no attention. 
It has been investigated very carefully in 
Germany in connection with the sugar- 
beet nematode. There it has been found 
that by greatly increasing the potash the 
injury is to a large extent, decreased. I 
am now beginning similar experiments 
with the root-knot. 
The method, however, that has perhaps 
