November 21, 1919] 



SCIENCE 



485 



node. Affected plants were sickly in growtli, 

 yellowish in color and showed little or no 

 stooling. 



Later reports, especially from Cowlitz 

 County, showed that the disease was respon- 

 sible for uneven stand in the field with con- 

 siderable lodging, the stems breaking over 

 near the surface of the grovmd. As reported 

 the disease showed no relation to type of soil 

 or system of culture. The disease also ap- 

 peared on oats and barley but in less severe 

 form and showed more of a general blacken- 

 ing of the base of the stem and death of roots. 



The disease was reported from Cowlitz, 

 Snohomish and Thurston counties on wheat 

 with the greatest severity in Thurston county, 

 while it was reported from Cowlitz county as 

 causing most injury to maturing grain. Ke- 

 ports of the disease on barley were received 

 only from Pierce coimty. On oats the disease 

 occurred in Clarke, Pierce and Snohomish 

 counties. The wheat crop in certain localities 

 of Cowlitz and Thurston comities suffered 

 material injury while no data are at hand to 

 show that the disease caused any material 

 damage to the other cereals. 



In 1902 Cordley^ reported a foot-rot of 

 cereals in Oregon but gave only a brief de- 

 scription of the disease and did not determine 

 the causal organism. The disease he mentions 

 is undoubtedly identical with the disease 

 which appeared during 1918 in western Wash- 

 ington. 'No other occurrences of the disease 

 in the united States are recorded. The dis- 

 ease is either a newcomer or has escaped 

 general notice up to the present time. 



A very careful microscopic study of the 

 fungus found in the stem lesions was made 

 in the attempt to determine the fungus. The 

 mycelium was sterile, dark brown in color, 

 with constrictions at the origin of side 

 branches. The mycelium agreed fairly well 

 with Rhizoctonia solani Kuhn., except in the 

 diameter of the hyphse which were only about 

 half as large. In case of plants showing a 

 very pronounced blackening at the base of the 



1 Cordley, A. B., Ann. Bpt. Ore. Agr. Expt. Sta., 

 1912, pp. 66-67. 



culm it was found that this was due to a 

 very compact siirface grovrth of dark brown 

 hyphae, approaching in some cases almost to a 

 sclerotial formation. 



No fruiting stage of the fungus has as yet 

 been connected with the sterile stage on the 

 base of the culms. Until this is done we can 

 only compare symptoms, and vegetative char- 

 acters of the fungus with published descrip- 

 tions of foot-rot diseases of cereals. There 

 seems to be a very close similarity between 

 the disease as it occurs in Washington and 

 the foot-rot of cereals caused by Ophiobolus 

 graminis Sacc, as described by McAlpine' 

 and others. 



Ophiobolus graminis and other foot-rot 

 fungi are knovsm to produce an ascigerous 

 stage on old stubble, so it seems probable that 

 the fungus causing the foot-rot of cereals in 

 western Washington will be found to have a 

 perfect or ascigerous overwintering stage on 

 the stubble of affected plants. There is also 

 a possibility of the disease occurring on the 

 native grasses. It is on these wild hosts that 

 some of the foot-rot fungi are known to be 

 carried through a crop rotation. It has not 

 been possible to make a careful field study 

 for the discovery of the ascigerous stage. In 

 the limited work undertaken a species of 

 Pleospora is the only perithecial form that has 

 been found in the old wheat culms. It is not 

 yet possible to say whether the disease in 

 Washington is identical with any of similar 

 European or Australian diseases. 



Eeports indicate that the disease is already 

 rather widely distributed in western Washing- 

 ing and Cordley's account of the disease 

 would indicate that it may have been present 

 for a considerable time. Time alone will 

 determine whether the disease will become as 

 serious as the foot-rot diseases of cereals in 

 Europe and Australia have been. 



B. F. Dana, 

 Assistant Plant Pathologist 



Agricultural Exp. Station, 

 Pullman, Wash. 



2 McAlpine, D., ' ' Take-All and "Wiite Heads in 

 Wheat," Bui. Dept. Agr. of Victoria, 9: 1-120, 

 1904. 



