﻿Halsted : Mycological Notes 



161 



have not complained of the rot. I do not remember of finding 

 Phytophthora at all destructive during the period from 1889 to 

 1897; but the last- season it was so abundant upon the experi- 

 ment plots that the crop of potatoes was harvested unusually 

 early to make sure of results in other directions. Nearly every 

 leaf upon every plant showed first the frosty coating followed in a 

 day or two with the wilting of the leaves. 



It seems to me that the Phytophthora or late blight is quite de- 

 pendent upon an abundance of moisture in midsummer, and if this 

 relation is noted sufficiently the time may come, it may be predicted 

 with reasonable certainty, 

 that a wet July will mean a 

 decaying potato crop, unless 

 some successful method of 

 checking this rapidly devel- 

 oping fungus is employed, 

 and, contrariwise, a dry mid- 

 summer will insure freedom 

 from its ravages. 



The Phytophthora of Lima 

 Beans, — In connection with 

 what has been said above- 

 concerning the influence of 

 copious rainfall upon the 

 unusual development of the 

 potato rot 



fungus 



it is in 



order to report that another 

 member of the genus Phytoph- 

 thora has been complained of 



bitterly during the season of 

 1 897. The mildew of the lima 

 eans, Phytophthora phaseoli 

 Thax., is a comparatively new 

 one, having been described 

 by Dr. Thaxter only eight 

 years ago* and figured in the 

 Annual Report of the Con- 



b 



* botanical Gazette, 14: 273. N. 1889. 



