Mat 6, 1910] 



SCIENCE 



717 



will be given in the final report for any assist- 

 ance of this character, should such be sub- 

 mitted to the writer. 



Frank C. Baker, 



Curator 

 Chicago Academy of Sciences 



^ COLLETOTRICHUM FALCATUM IN THE UNITED 

 STATES 



During the past two years, while studying 

 the diseases of sugar-cane, careful search has 

 been made for those which are troublesome in 

 other countries but which are not known to 

 occur in the United States. During the past 

 year one of these has been found in Louisiana, 

 and from material received from another state, 

 this may be more widely distributed than was 

 at first thought. This disease is one which is 

 caused by the fungus CoUetotrichum falcatum 

 Went. This has been reported previously in 

 nearly every sugar raising country in the 

 world, in some places doing a large amount of 

 damage. According to Butler' this fungus 

 sometimes causes an immense loss in Bengal. 

 Several common names have been applied to 

 this disease, but the one in most common use 

 in English-speaking countries is the red-rot 

 disease. 



The first specimen of this disease was found 

 on a plantation in Orleans parish, Louisiana, 

 in September, 1909. One cane was found 

 which had a lesion about two centimeters in 

 diameter which was covered with the fruiting 

 pustules of this fungus. No other diseased 

 stalk was found in the field. I was not will- 

 ing to make a positive identification at the 

 time because the causative fungus is very 

 similar to CoUetotrichum lineola Cda., which 

 occurs very abundantly on Johnson Grass in 

 this region, and it was barely possible that 

 this latter fungus had gained an entrance 

 into a wound in the cane. But since other 

 material has been received there seems little 

 doubt but what this was the true red-rot 

 fungus. 



^ Butler, E. J., " Fungus Diseases of the Sugar- 

 cane in Bengal," Memoirs Dept. Agr. in India, 

 Botanical Series, Vol. 1., No. 3, Pusa, 1906. 



During the fall and winter of 1909 and 

 1910, a planter in Georgia, Mr. W. B. Eod- 

 denbery, of Cairo, who has had considerable 

 trouble with a disease in his cane wrote to the 

 sugar station at New Orleans and also sent 

 specimens. This material was resent to me 

 and I have since made a careful study of the 

 trouble. There is no doubt but that it is 

 the red-rot disease in a very serious form. He 

 estimates that one third of the cane which he 

 wished to use for planting was diseased. 



As this disease is generally confined to the 

 inside of the stalk, an examination of the ex- 

 ternal part usually shows but very little of the 

 trouble. Unless the cane is severely affected 

 the disease would ordinarily be overlooked, 

 unless it was examined very carefully or un- 

 less the stalks were split. However, when the 

 cane is severely ailected, the rind covering the 

 nodes, and even strips on the internodes, be- 

 come dark brown in color, and the eyes are 

 usually dead. H the stalks are split, the 

 nodal region will be found to be badly de- 

 cayed, with strips of red and brown extending 

 out into the internodes. One of the distin- 

 guishing characters of the disease is the pres- 

 ence of light-colored spots surrounded by red 

 or brown tissue. These were fairly abundant 

 in the Georgia material. These have not been 

 satisfactorily explained but it appears as if 

 they are points where the fungus is present, 

 it generally not being present in the red and 

 brown surrounding tissue. 



The fungus was found fruiting in some 

 large internodal lesions on some soft top 

 joints of one stalk, on the brownish colored 

 nodes of two stalks, and also fruited on a 

 split stalk that was kept moist. In the latter 

 case, the fruiting postules developed directly 

 from the diseased center of the node. A 

 microscopical examination of the diseased 

 tissue of the cane showed the presence of the 

 typical mycelium and many of the so-called 

 " appressoria " in the host cells. 



This fungus is very similar, if not identical 

 from a morphological standpoint, to CoUeto- 

 trichum lineola Cda., mentioned above. The 

 latter fungus has also been studied and inocu- 



