16 BULLETIN 134, TJ. S. DEPARTMENT OF AGRICULTURE. 



SUMMARY. 



The results of this preliminary investigation show that a disease of 

 wheat comparatively new to this country and to the grain trade is 

 established in certain areas of the United States, particularly in cer- 

 tain sections of Virginia. This disease not only reduces yields per 

 acre but also seriously affects market grades and milling qualities of 

 marketed wheat, on account of the presence in the grain of a pecul- 

 iarly misshapen black gall, which can be removed only with diffi- 

 culty and which is the resting place of the invading organisms. 



The presence of the galls in a parcel of wheat reduces the' market 

 grade in several ways. Its presence reduces the test weight per 

 bushel because of its lighter weight. It also increases the amount of 

 dockage and particularly the amount of foreign material other than 

 dockage in any given lot of infected grain. 



Flour yield from such infected wheat is reduced, and the per- 

 centage of low-grade flour and shorts is increased. Ordinary wheat- 

 cleaning machinery will not remove these galls successfully, although 

 machinery for washing and drying wheat will no doubt be successful. 



The best known methods of control are crop rotation and clean 

 seed. To kill the nematode larvae, infected seed may be treated by 

 the hot-water treatment used for the control of smut to kill the nema- 

 tode larvae. The easiest method and the least dangerous practice to 

 obtain clean seed is to float the galls away from the sound wheat by 

 means of water. 



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