1922] 



ROSEN — A BACTERIAL DISEASE OF FOXTAIL 343 



disease is widespread throughout Arkansas. No effort has so 

 far been made to locate the disease in other states, so that little 

 is known concerning its distribution. It should be looked for par- 

 ticularly in the warmer sections of the country, since physiologi- 

 cal studies indicate that the organism grows best at relatively 

 high temperatures. Field infections on foxtail are at times se- 

 vere, especially during warm, moist weather. Under such condi- 

 tions it is not uncommon to find individual plants with almost 

 every leaf-blade killed and with only the rachis and head show- 

 ing a normal, green color. Lower leaves in particular are to be 

 found diseased (indicating infections by spattering of rain drops). 

 However, considering the extent of injury as observed over a 

 period of several years there is no reason for viewing this disease 

 with alarm. On one particular field where it has been under close 

 observation for more than three years, the disease has occurred 

 on 4 successive crops of foxtail without any apparent diminu- 

 tion in the number of volunteer plants that sprang up. Every 

 year this field had been plowed, cultivated, and used for growing 

 tomatoes and other crops, and by late summer, unless considera- 

 ble hoeing were done, foxtail would "take" the field. In this con- 

 nection it is worth while calling attention to the distribution 

 and growing season of the host. Yellow foxtail is common in 

 cultivated soil in the eastern United States (it is also very com- 

 mon in the Mississippi region) according to Hitchcock (U. S. 

 Dept. Agr. Bull. 772, p. 243) and is "often sufficiently abundant 

 to furnish considerable forage." It usually does not appear be- 

 fore midsummer and comes into full development by late August 

 or early September. Thus we see a high, midsummer tempera- 

 ture favoring host development as well as that of parasite. 



SUSCEPTIBLE VARIETIES OF COMMON CEREALS 



The following varieties of common cereals 1 have been found 

 susceptible in artificial infection experiments by methods which 

 will be explained below. For each variety listed one or more 

 pots each containing numerous plants were inoculated. When 

 infections were few or uncertain other pots of the same variety 

 were tried. Uninoculated plants served as checks. Because of 

 rapidity of growth as well as ease of handling, seedlings 6-12 



1 The writer wishes to express his indebtedness to the Agricultural Experiment 

 Station of the University of Arkansas and in particular to Professor W. H. Sachs 

 for supplying most of the seed of the varieties listed. The varieties are for a 

 large part those that are adaptable to Arkansas conditions. 



