712 
Journal of Agricultural Research 
Vol. XXIII, No. 
coat may lie dormant for months. It is very unlikely that any of the 
heavier seed carry infection inside the seed coat. Simply floating off 
the lighter seed in water, therefore, would eliminate a large part of the 
danger of transportation of the disease through this means. Experiments 
in this connection have shown, however, that a considerable proportion 
of the apparently normal seed will float in water when first immersed, 
and also that seed which were heavy enough to sink at first may rise 
later. In a specific trial, half of a lot of 50 seeds floated when first put 
in the water; in 30 minutes 8 more had risen; after an hour longer 8 
were floating and 42 were on the bottom. Several different lots acted 
the same way, in general. It is recommended, therefore, that, in order 
to combine the floating process with seed treatment, some such precedure 
as the following be practiced, if there is chance that the seeds are infected. 
The seeds should be immersed in water in a large receptacle and left for 
about \% hours with frequent stirring. Then the disinfectant, prefer¬ 
ably formaldehyde, should be added in the proper proportion, and the 
seeds left for 15 minutes longer. At this time all those that are floating 
should be skimmed off, together with all trash, and discarded in so far as 
use for seed is concerned. It is true that many good seeds will probably 
be discarded along with the poor, but they will still be available for oil, 
and the certainty will be the greater that only the best and cleanest 
seed is reserved for planting. 
GENERAL RECOMMENDATIONS FOR CONTROL 
Regardless of the freedom of seed from disease, planting castor beans 
in a locality where the disease is present is almost certain to bring about 
a diseased crop. Observations made in April, 1921, three years after 
the war emergency plantings of 1918, showed the disease to be still 
present and active at Orlando, Fla. Several castor bean plants that 
had survived the mild winter of 1920-21 and had grown to be trees 15 
feet high and 6 inches in diameter at the base were covered with fruiting 
spikes in different stages of maturity. About 50 per cent of these were 
affected with the typical gray mold. The first requirement, therefore, 
toward the growing of a mold-free crop would be planting in a mold-free 
locality. Planting in locations where climatic conditions are not favor¬ 
able to the disease would be a still better safeguard, in that no infections 
could occur from chance introductions of the disease on seed or otherwise. 
The map (fig. 1) shows the localities in America where the disease 
occurred and where it did not occur, in 1918. Several States, in some 
of which in fact, the best yields were produced, are seen to be suitable 
in this respect. In case the necessity should ever recur for heavy plant¬ 
ings in America, this should be one of the primary considerations. A 
study of the rainfall maps over a considerable period might be advisable 
in order to be certain that the 1918 conditions were not exceptional. 
After choosing the localities where the planting is to be done, the source 
of seed should be considered. If there is any doubt about the cleanness 
of seed, 15 minutes’ treatment, in either formaldehyde solution or 
mercuric chlorid, as recommended above, should be given as an addi¬ 
tional safeguard. Only as a last resort, to prevent general spread from 
a limited primary infection, can spraying or dusting be recommended. 
If accompanied by complete destruction of all the disease that has been 
found, and if repeatedly and frequently applied, a fungicide might be 
helpful. But on the whole such measures are not recommended as 
