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NEMATODE GALLS IN MARKET WHEAT. 15 
to remain in the water for only as long as absolutely necessary for a 
thorough removal of the galls or the germination will be affected. 
To summarize, clean seed obtained from outside sources, or seed 
cleaned by means of floating the galls out of the infected wheat with 
water, combined with crop rotation, seem to be the most effective 
methods of controlling this disease at the present time. Experiments 
in which the Bureau of Markets is cooperating are now being con- 
ducted by the Bureau of Plant Industry on additional methods for 
controlling this disease, the results of which will be reported in the 
future.* 
The disease propagates easily. This has been brought out several 
times from the investigations carried on throughout the infected 
area. One method of propagation is the planting of infected seed 
wheat. For example, one particular crop which contained these 
galls was sold for seeding purposes. Without exception the next 
season every farmer who purchased this seed had an infected crop 
regardless of the fertile condition of the soil. Farmers who 
planted their own infected seed harvested each year a greater pro- 
portion of galls. The highest proportion of galls to sound wheat 
coming to the attention of the Department of Agriculture was 25 
per cent. 
Some of the mills which do a seed-cleaning business as a side line 
return the screenings to the owners to be used for feed. If these 
screenings contain nematode galls and are given to fowls and stock 
for feeding purposes they constitute an important means of spread- 
ing the disease. Feeding experiments? indicate that the gall is not 
digested in all cases, but finds its way into the manure intact. When 
this manure is spread over the land the land is thus inoculated with 
these nematode galls, and if wheat is again planted two sources of 
infection, the seed and manure, are acting to supply infectious ma- 
terial for the young seedling. It is apparent that such screenings 
should be burned even at chance of losing some feed. The material 
removed from infected wheat by floating should also be burned as a 
precaution against further distribution of this disease. 
Further experiments on this disease from a milling, grading, 
and distribution standpoint are now being carried forward by the 
Bureau of Markets in order that a better knowledge of the commer- 
cial importance of this material as a foreign material in wheat may 
be obtained. 
1U. S. Dept. of Agriculture, Office of the Secretary, Circular 114. <A Serious eelworm 
or nematode disease of wheat. 1918. 
2 Marcinowski, K. Parasitich und semiparasitsch an Pflanzen lebende Nematoden. K. 
Biol. anst. F. land un forstw. Arb. bd., 7 hft. 1, p. 1-192, pl. 1, Berlin, 1909. 
