THE OPHIOBOLUS CAUSING TAKE-ALL OF 



WHEAT 



H. M. Fitz Patrick j H. E. Thomas, and R, S. Kirby 

 (With Plate io and i Text Figure) 



The discovery of perithecia of a species of Ophiobolus in July, 

 1920, at East Rochester,, New York, on wheat plants showing 

 characteristic symptoms of the take-all disease was reported in an 

 earlier paper. 1 Subsequently additional collections of the fungus 

 have been made in scattered localities in New York, and reports 

 of its occurrence in other states have been received. The fungus 

 has also been obtained in pure culture, and repeated inoculations 

 have demonstrated it to be the causal organism of the take-all dis- 

 ease. Normal perithecia with mature asci and spores have devel- 

 oped in culture, and a comparative study shows the organism used 

 in the inoculations to be identical with that collected in the field. 

 A paper dealing with the various aspects of the experimental work 

 and embracing a discussion of the parasitism of the fungus has 

 been submitted for publication. 2 In the present paper only facts 

 bearing on the identity of the organism are considered. 



In the historical and bibliographic discussion of the take-all dis- 

 ease prepared by Stevens 3 a number of papers are cited in which 

 the discovery of perithecia of Ophiobolus in connection with dis- 

 eased plants is reported. Two species, 0. graminis Sacc. and O. 

 licrpotrichus (Fr.) Sacc, are mentioned repeatedly. It has seemed 

 necessary to compare our fungus carefully with these and other 

 species of Ophiobolus occurring on grasses, as well as with various 



1 Kirby, R. S., and Thomas, H. E. The take-all disease of wheat in New 

 York. Science, N. S. 52: 368-369. 1920. 



2 Kirby, R. S. The take-all disease of cereals and grasses. Phytopathology 

 for January, 1922. (Abstract of paper presented at annual meeting of Phyto- 

 pathological Society at Toronto/ December 28, 192 1. Complete paper not yet 

 published.) 



3 Stevens, F. L. Foot-rot disease of wheat — historical and bibliographic. 

 Bull. Nat. Hist. Survey. Illinois Dept. Registration and Education 13 : 259- 

 286. 1919. 



30 



