14 BULLETIN 734, U. S: DEPARTMENT OF AGRICULTURE. 
smut, i. e., seed immersed in a solution of copper sulphate (1 pound 
of copper sulphate to 4 gallons of water) for three minutes is not 
an effective method for killing the nematodes, because in this length 
of time the solution does not pass through the hard covering of the 
gall. 
The modified copper-sulphate treatment of soaking the seed for 12 
hours ina solution of the strength 1 pound of bluestone to 25 gallons 
of water has not proved successful in killing these worms. 
Experiments show that soaking seed in 0.6 per cent sulphuric acid 
for 24 hours is an efficient method of killing the contents of the gall. 
This sulphuric-acid treatment is so subject to variations in the hands 
of an inexperienced operator that it can not be recommended for 
treatment of seed infected with-these galls, however, as the germina- 
tion of the seed is greatly decreased. 
The hot-water treatment for smut, which is described in Farmers’ — 
Bulletin 507,1 and which consists essentially of immersing seed 
for 10 to 15 minutes in water at a temperature of 135° F., has like- 
wise proved successful in killing the nematodes. This test, however, 
unless properly carried out, is also lable to injure the sound seeds 
and for this reason can not be recommended without reservation. 
The most feasible method of removing the source of infection from 
sound wheat seems to be by floating the galls out in cold water. The 
nematode galls are lighter than sound wheat kernels, and this differ- 
ence in weight is made use of in their separation. <A suggested 
method follows: 
Have two tubs or half barrels, one set above the other so that the 
overflow containing the galls will fall into the lower tub. Cover 
the lower tub with cheese cloth to catch the galls but let the water 
run through. [ill the upper tub with water to overflowing. Next 
pour the infected wheat into the top barrel slowly at the same time 
stirring vigorously. The galls and light chaff will rise to the top 
and float off when assisted by hand or skimmer, and will be caught 
on the cheesecloth over the lower tub. When vigorous stirring brings 
up no more galls pour or drain off the water. Air drying is accom- — 
plished quickly and easily if the wet grain be spread out to dry on a 
canvas or on a clean barn floor. The dampened grain should not be 
allowed to lie in a heap as the kernels will not dry out regularly ; some 
will sprout and danger of heating is present. 
The seed may be planted as soon as it will run freely in a drill or 
may be dried thoroughly and stored for future use. Experiments 
carried out by this method have resulted in the removal of over 99 
per cent of the galls. -It is recommended that the grain be allowed 
1 Johnson, Edward C. ‘The smuts of wheat, oats, barley, and corn. U. S. Dept. of 
Agriculture, Farmers’ Bulletin 507. 1912. 
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