﻿Halsted : Mycological Notes 159 



only one showed the rust at all, while all of the untreated plants 

 were more or less badly rusted. Here is an instance where spray- 

 ing proved very effective against such a rapidly developing and 

 deeply seated enemy as the hollyhock rust. The sprayings were 

 made at intervals of about ten days varying somewhat and depend- 

 ing upon the weather. 



Observation in Wind-infection of a Rnst. — An instructive in- 

 stance of one-sided infection was observed the past season in 

 connection with the asparagus rust {Puccinia asparagi DC). 

 On September sixth, while inspecting asparagus fields in Glou- 

 cester County, New Jersey, the writer came to a field with quite an 

 unusual green appearance, nearly all the fields being brown and 

 lifeless so far as the brush was concerned, having been killed by 

 the remarkable ravages of the rust fungus. The field in question 

 had been cut over and the very rusty brush removed about five 

 weeks before, with the hope that the new growth might escape the 

 ravages of the Puccinia. At the date of the inspection the brush 

 was about hip high and showing the rust only upon one side of 

 each plant. So strikingly one-sided was the output of the rust 

 sori that one could scarcely fail to observe it. Every main 

 stem was almost completely covered with the rust upon one side, 

 while the opposite bore almost no spots. It was also noticed that 

 this rusted side varied somewhat at different ends of the long field, 

 and at all points was at right angles to lines drawn from an old 

 and very badly rusted bed of asparagus that stood with its end to- 

 ward the broad side of the field in question and about forty rods 

 away. 



This observation teaches something concerning the rapidity of 

 the development of the rust fungus. As the brush must needs 

 have been developed to some extent before the uredospores could 

 have alighted upon them, and also it is fair to judge that many of 

 the sori upon the plants were fully ten days -old, and, therefore 

 not more than two weeks might have elapsed from the time when 

 the spores came to the asparagus plants to that when sori were 

 giving off their spores. The season was unusual, July being a 

 very rainy month, and the long wet spell continued into August, 

 followed by hot, moist weather particularly favorable for the de- 

 velopment of fungi. 



