STUDIES OF GLOMERELLA FROM DIFFERENT HOSTS. 35 



GOSSYPIUM HIRSUTUM L. (COTTON). 



Glomerella gossypii Edge. 

 Colletotrichum gossypii South. 



DEVELOPMENT ON BOLLS AND STEMS IN MOIST CHAMBER. 



On February 20 leafless tips of cotton stems received from Lome, 

 Togoland, western Africa, were treated as usual and placed in sterile 

 moist chamber. These specimens showed dried whitish patches, sug- 

 gesting old acervuli of Colletotrichum gossypii, but no conidia could be 

 found. On February 23 acervuli with the characteristic brown setas 

 of this species were present on the stems. Transfers from these 

 acervuli to flasks of corn meal produced an abundant growth of 

 conidia and a dark mycelium but no perithecia. 



On May 7 eight apparently healthy bolls about three-fourths grown 

 were taken from a single plant in the greenhouse. The surface was 

 sterilized as usual and the bolls placed in a moist chamber. On May 

 22 these bolls were more or less discolored, but no fungus was visible. 

 On May 25 one of the largest bolls was almost completely covered 

 with acervuli of Colletotrichum gossypii. On June 17 four other 

 bolls also showed a,cervuli. As these bolls had been in the same 

 chamber with the other, it is possible that infection came from the 

 first boll. 



On June 22 five other bolls of various ages were treated in the same 

 way, but no Colletotrichum developed on any of them. These 

 experiments would appear to indicate that the fungus on the cotton 

 is able to live in a dormant or hibernating condition, as has been 

 found to be the case with most of the other forms. 



CULTURES. 



On October 28, 1905, sections from a diseased cotton boll were 

 transferred to flasks of corn meal. These all developed a growth 

 resembling that of the cotton anthracnose, and on November 23 one 

 flask showed acervuli with pink masses of conidia and also perithecia 

 with aseospores not quite mature. All the other flasks showed a lux- 

 uriant growth of a white mycelium and conidia. Transfers were made 

 from a flask producing perithecia. These also produced perithecia 

 and aseospores. 



Tests were also made of the effect of corrosive-sublimate solution, 

 1 to 1,000, on conidia of this fungus, the spores being treated from 

 five to seven minutes and then transferred to poured plates. Check 

 plates were made at the same time to determine the vitality of the 

 spores. The checks grew luxuriantly, but no growth appeared in the 

 plates sown with spores treated with corrosive sublimate, indicating 

 that they had all been killed. 



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