366 



Reed : The mildews of the cereals 



TABLE XV. 



Results with Secale moniamim Guss. 



o a 



Is. 



146c 

 IS 9b 

 170a 



1 86b 

 187a 

 199a 

 199b 

 199c 



Date 



1908 



Oct. 31 

 Nov. 10 



(4 



<< 



Dec. 



i< 



20 

 27 



27 



14 



Source of conidia 



Secale cere ale 



C I< 



c 



i 



ti 

 a 

 tt 



ti 



^The first and third leaves inoculated. 

 2 Two leaves of each plant inoculated. 







m 



2 



CA 



'o 



(3 



*^ 11 



u 



ttf ^^ 



rt i: 



a 









 •J 



-a 





 







li^ 



o.S 



1 JJ 







< 



^ 







12 



I 



22 



li 



I 



17 



22 



I 



13 



1 = 







24 



2^ 



2 



23 



3 







30 



I 



1 







23 



I 







Results 



Date 



1 



Inoc. 

 plants 



1908 





Nov, 7 





" 19 





'' 26 



1 



Dec. 5 



+++ 



" 5 





'' 23 





'' 23 



+++ 



cc 23 



++4- 



Controls 



Out of the eleven species of Hordetun tested with the barley 

 mildew, seven {Hordciim distichon, H. midiim^ H. Stcudelii x H. 

 irifiircatiLm^ H. tetrastichon, H, trifurcatiun, II. vtdgare, and //". 

 Zeocrifon) proved perfectly susceptible. Infection occurred on 



every plant that was inoculated. 



One species {Hordeiun nodosiini) gave a very large percentage 

 of infection, fifty-one plants out of the sixty-four inoculated be- 

 coming infected. According to the Index Kewensis, this species 

 is the same as HordcJtm sccalinum Schreb. Salmon"^ claims that 

 H. sccalinum is entirely immune to the barley mildew. I am un- 

 certain whether Salmon was working with //. secali7iimi Schreb- 

 or whether he had some other species of Hordetun listed under 

 this specific name. It is clear from my results that young plants of 

 Hordciim nodosum are quite susceptible to the barley mildew. 

 Older plants, however, appear to be immune, for in every case 

 where the second green leaf was inoculated, no infection occurred. 



When plants of Hordetun btilbosiim were inoculated with conidia 

 from barley, only one leaf out of the twenty -four inoculated became 

 infected. It is interesting to note that Salmon secured only one 

 positive result out of fourteen inoculated plants, and Marchal 

 reported the results with this plant as negative, when conidia from 

 barley were used. This species evidently is practically immune 

 to the barley mildew. 



In my experiments I was unable to infect Hordeiun jttbatnm 



