174 abstracts: phytopathqlogy 



destroys the infective principle much less readily than ethyl alcohol. 

 In ethyl alcohol the infective principle is destroyed rather quickly in 

 alcoholic solutions stronger than 50 to 55 per cent. Eighty per cent 

 alcoholic strengths killed the virus in less than half an hour. Chloral 

 hydrate, benzoate of soda, quinine bisulphate, naphthalene crystals, 

 camphor, thymol, and glycerin, except in very strong solutions, reduced 

 the infectivity of the virus but little. The virus shows itself con- 

 siderably more susceptible to solutions of formaldehyde, a 4 per cent 

 strength destroying the infective principle very quickly. When the 

 virus is mixed with talc, kaolin, or soil, it frequently loses its infectious 

 properties more quickly than when merely bottled without the addition 

 of any preservative. H. A. A. 



PHYTOPATHOLOGY. — A serious eelworin or nematode disease oj 

 wheat. L. P. Byars. U. vS. Dept. Agr. Circ. 114. July, 1918. 



During the past year the eelworm disease of wheat, caused by 

 Tylenchus tritici (vSteinbuch) Bastian and long known in Europe, has 

 been found causing a great deal of damage in certain parts of the 

 United States, particularly in Virginia. Recent examinations have 

 shown a loss in some fields of as much as 40 per cent of the crop. 



Wheat spikelets affected by the disease contain in place of the normal 

 kernels dark, hard galls filled with larvae of the nematode. These 

 larvae escape from the galls into the soil, reach the young seedlings, 

 become located between the leaf sheaths near the bud and are passively 

 elevated to the spikes. There they enter the young flowers and pro- 

 duce the galls within which they develop to maturity and lay eggs. 

 The latter give rise to larvae and in this way their life cycle is com- 

 pleted. 



The disease may be controlled by the use of clean seed, crop rota- 

 tion, and sanitation. If uninfected seed cannot be brought in from 

 localities where the trouble does not occur the sound grain may be 

 separated from the nematode galls by floating off the latter in water. 



L. P. B. 



