NEMATODE GALLS IN MARKET WHEAT. 13 



It was thought that this temperature would be sufficient to kill all 

 the larvse, but Mr. Thomas states that it is quite unlikely that the 

 small amount of steam used would penetrate any deeper than the 

 outside coats of the berry. Of course, during the baking process, all 

 larvae would be killed, which were not killed in the milling operation. 

 They are still present in a macerated condition, and it would seem for 

 sanitary reasons that they should be removed. 



Notice has also come to the attention of the Department of Agri- 

 culture that some farmers mill their own flour from this infected 

 wheat. Knowing the content of these galls, this practice is repulsive, 

 and it is recommended that in the future, wheat for home milling be 

 carefully inspected for the presence of these nematode galls, and 

 that they either be removed by floating or that such wheat be re- 

 jected or diluted with sound wheat until a negligible amount of galls 

 is present. 



METHODS OF CONTROL AND DISTRIBUTION. 



It is apparent that if this disease is allowed to increase it will be- 

 come a serious factor in the marketing and milling of wheat, and, 

 therefore, known methods for its control should be made public at 

 the present time. 



Apparently, no previous extensive experiments have been carried 

 out for the purpose of controlling this disease in this country. No 

 doubt the prime essentials for effective control are clean seed and 

 crop rotation. Past experiments indicate that the nematodes must 

 have either the gall or the host plant present as a protection, other- 

 wise they do not live long in the soil in the active state. Also, it 

 seems to have been shown that, of the common field crops, this 

 nematode seriously attacks wheat only. It would seem, then, that 

 a crop rotation of two or more years would be effective in practically 

 ridding a field of this pest. 



The use of clean seed, either by the buying of new seed from out- 

 side sources or by the planting of seed which has been properly 

 cleaned, has been shown to reduce the infection in a number of 

 instances throughout the infected area. 



A number of ways for cleaning the infected grain have been tried 

 and suggested. Bessey suggests that grain containing these galls 

 be given the hot-water treatment, as carried out for the stinking 

 smut of wheat, in order to kill the nematodes. Cobb 1 mentions 

 winnowing. Steeping in a .2 to 5 per cent solution of sulphuric 

 acid for one-half to two hours as a means of ridding seed of these 

 organisms has also been suggested. 



It has been the experience of several farmers, as well as that of the 

 Grain Standardization Laboratory, that the bluestone treatment for 



iCobb, N. A. Cited by Johnson. 



