44 PAEASITES BELONGING TO THE GENUS GLOMERELLA. 



PERSEA GRATI3SIMA GAERTN. F. (AVOCADO). 



Glomerella cingulata (Stonem.) S. and v. S. 



DEVELOPMENT ON LEAVES IN MOIST CHAMBER. 



On January 15 apparently healthy leaves from a greenhouse plant 

 with the surfaces sterilized as usual were placed in a sterile moist 

 chamber. Dark spots soon appeared on these leaves, and on Febru- 

 ary 3 an abundance of acervuli with pinkish masses of conidia were 

 present. No perithecia were found. 



On July 1 other leaves of normal appearance from the greenhouse 

 were treated in the same manner as the preceding. On July 26 

 numerous acervuli were present and also perithecia with immature 

 asci. Later, mature asci and spores were found. 



On December 30 leaves showing small dead areas were taken from 

 the same source and treated in the same manner as above. On 

 January 7 abundant acervuli with setae were found on one of the 

 leaves. On January 17 a few mature perithecia were found on the 

 same leaf. They were characterized by unusually long beaks. 

 Later, acervuli and perithecia developed on the other leaf also. 



CULTURES. 



On December 18 five plates were poured, using conidia from a 

 single acervulus on avocado fruit received from Miami, Fla. A few 

 setae were present in this acervulus. Three single germinating conidia 

 were transferred to tubes. On January 5 both plates and tubes 

 differed in appearance from the earlier cultures from Persea, especially 

 in the scarcity, or almost complete absence, of conidia. A few dark 

 stromatic bodies were present in the plates, but no perithecia. A very 

 few acervuli finally developed in the tubes, but no setae or perithecia 

 were found. 



On January 6 plates were poured, using conidia from acervuli which 

 had developed upon an apple inoculated with conidia from the same 

 avocado fruit. A loose white growth of mycelium was produced, 

 bearing very few conidia. These cultures differed conspicuously 

 from plates poured at the same time, using conidia from the avocado 

 fruit. The growth was much more abundant in the latter case and 

 the conidia more numerous, suggesting the possibility that the fun- 

 gus had lost some of its vitality through its development on the 

 apple. A few setae were found later and a few apparently immature 

 perithecia finally developed. 



On January 6 more plates were poured, using conidia from the 

 same avocado fruit. A luxuriant white growth soon developed, pro- 

 ducing an abundance of conidia but no distinct acervuli. Transfers 

 to tubes from these plates produced acervuli with an abundance of 

 setae and a few apparently immature or sterile perithecia. 



252 



