DAMPTNG-OFF JIN" FOREST NURSERIES. 5 



saprophytes that one of them might easily get into a killed seedling 

 after some other parasite had caused its death. Not only in the 

 case of seedlings killed by fungi like Peronospora parasitica, but in 



HOST 

 YERR 

 EXPT. 



PMV3 



GTHOBUS 



/°//V^<5 0/9A/MS//9A//? 



P/HiAS 



POA/oepos/r 



PINU3 RES/NOSA 



/9/3 



/9/3 



/9/4- 



/9/4- 



1917 



/9/3 



28 A 



28 B 



31 



36 4-7 



IS 



7/ 



72 



- 





''* A 





i \ 



1 V 



/■ \ ■ 

 / \ 

 ' 1- \ 



- 



^' 



\ N / \ 

 \ V / \ 



l 



i 



'/ \ 



/ / **^ J 3 



f / ^» 







V £ * \ 

 J* N \ 

 N \ 

 \ \ 



v V 



J ' 

 // 







*-«^ *--J 



--^fi 





1 



i . i _i 



l 



i i 



s o - 



Fig. 1. — Diagram showing the relative activity of different strains of Corticium vaf/um 

 in inoculations made at the time of sowing the seed. In experiments Nos. 36, 45, and 

 47 the values are plotted for the number of seedlings appearing above the soil. For the 

 other experiments the number of seedlings surviving at the close of the experiment have 

 been taken. Explanation of symbols : 0=Strain 147, from spruce seedlings, Washington, 

 D. C, 1910 ; +=strain 50, from pine seedlings, Nebraska, 1909 ; D =strain 233, from 

 Elaeagnus sp., Kansas, 1913 ; ■ =strain 230, from the same lesion as strain 233 ; 

 Q =strain 183, from bean, New York, 1910. 



HOST 

 YEAR 

 EXPT. 



%/SO 



I 



I eo 



I 



I 30 



P/MUS 

 •STPOBUS 



/°/rtaS BRA/HS/RA/R 



PINUS 



PONDEROSfl 



PIN US RESWOSfi 



/9I3 



/S/& 



19/4- 



IBIR- 



J9/3 



/9I7 



23 ft 



see 



31 



SI 



R-3 



72 



7/ 





y 



,-*■-- 



/ \ 



is. o, / 



% 

 \ 



\ 



\ 

 \ 



V 



\ 

 \ 



/ y 



' x 



*~~-a 



<0 



Fig. 2. — Diagram showing the relative activity of different strains of Corticium vagum, 

 as indicated by the number of seedlings surviving in inoculated soil. Explanation of 

 symbols : ©=Strain 189, from sugar beet, Michigan, 1910 (light-brown mycelium with 

 few sclerotia) ; A=strain 211 and A=strain 212, from sugar beet, Colorado, 1910; 

 H=strain 186, from potato, Ohio, 1910 ; D=strain 187, from potato, New York, 1910; 

 +=strain 205, from Douglas fir, Colorado, 1911 ; X =strain 192 and 0=strain 206, 

 from pine, Nebraska, 1911. 



cases of true damping-off produced by the rotting type of parasite, 

 much of the rapid decay of the seedling after death is brought 

 about by bacteria and fungi other than the one causing death. 



