160 The Ottawa Naturalist. [Feb. 



from the observations made that large numbers of apotheica 

 are produced in wet seasons and that the asci discharge immense 

 numbers of spores during the blossoming period. It is, therefore, 

 reasonable to suppose that the apothecia are one of the chief 

 sources of blossom infection which later may result in twig 

 blight. It is also possible that the ascospores account for much 

 of the infection of the young fruit. It also seems likely that the 

 apothecia are produced in more or less abundance every spring, 

 but as they wither very quickly when the weather becomes drv 

 they have not been observed, and hence the apothecial stage 

 has been regarded of little importance in the propagation of the 

 fungus and the continuance of the disease. 



The writer hopes to continue these observations, as it is 

 desirable to ascertain definitely the extent of the infection due 

 to the production of apothecia in order that proper measures 

 may be recommended for the control of this disease. Plowing 

 under the mummied fruits has hitherto been considered one of 

 the best means of preventing infection but if the apothecia are 

 produced from old fruits which have been buried a vear or more 

 in the soil and brought to the surface by fresh plowing, this 

 method would appear to be of little value. 



Observations on this fungus were continued in the spring, 

 of 1913. The apothecial stage was found in comparative abun- 

 dance in plum orchards near St. Catharines. In order to deter- 

 mine whether the apothecia developed from mummied plums 

 which had been buried in the soil for a year or more, or from 

 mummied plums of the previous season, a number of mummied 

 plums gathered in the spring of 1912 (the plums having been 

 destroyed by the Brown Rot during the summer of 1911) were 

 buried in loam and sand at different depths and left outside, 

 exposed to climatic conditions until the spring, of 1913. They 

 were then dug up and placed in moist chambers. Not a single 

 apothecium developed from any of them nor were there any 

 ones of the formation of sclerotia. Some mummied plums 

 gathered last spring, which had hung on the trees or lain on the 

 ground under the trees for the winter, were placed in moist 

 chambers at the same time. On one mummied plum which 

 had lain on the ground for the winter, a number of stunted, 

 poorly-developed apothecia appeared. This experiment, though 

 by no means conclusive, suggests that the apothecia may be 

 developed from mummies of the previous years. These experi- 

 ments and observations will be continued with the hope of 

 clearing up this and other obscure points in the life-history of 

 Sclerotinia cinerea. ^--."v. 



BRARY 



