LONGEVITY OF CONIDIA AND ASCOSl'OUES. 



TliL' Iciijiili of time tluit coiiidia retain tlieir power to ••('rniiuate 

 will doubtless vary with the ooiulitioiis under wliicli the spores 

 are kept. Spores from Itark collected in late summer and kept 

 dry at ordiiiaiy room temj^erature, germinated readily for four 

 months, but three weeks later could not be induced to germinate. 

 Material exposed out of doors and that kept moist and at altout 

 75 degrees F. in a greenhouse, did not give germination of coiiidia 

 after four Jiionths earlier tests not having been made. 



GERMINATION OF CONIDIA AND ASCOSPOEES IN DIFFERENT MEDIA. 



Both kinds of spores germinate in a decoction of chestnut bark, 

 in rice ]>rotb, etc, Ascospores germinate in spring water, the 

 conidia do not. 



EFFECT OF TEMPERATURE ON (JERMINATION. 



Coiiidia gerniiiiate best at a temperature of (10 degrees F., and 

 dis^tinctly less rapidly at temperatures 10 degrees above or below 

 this point. 



Ascospores germinate best at a temijerature of about 70 degrees 

 F., but a good percentage of germination occurs at 85 degrees F. 

 and 45 degrees F. Even at 38 degrees F. the germination of as- 

 cospores was 25 per cent, in the first 24 hours, and reached 70 

 per cent, in three days. Ascospores germinate readily after at 

 least moderate freezing. These facts indicate that the ascos- 

 ])ores may play a more im]>ortant }»art in causing infection undeT 

 certain conditions, than has been commonly attributed to them. 



The effect of extremely high and low temperatures on spores 

 has not yet been completely investigated in our laborator3^ 



EFFECT OF TEMPERATURE ON EARLY GROWTH. 



Ill gdieral lh(^ most rapid early growth is at the optimum tem- 

 perature for gerijiiiiaiion. In a nutrient solution of boiled chest- 

 nut bark, the a.scospores will send out a length of mycelium 10 

 to 15 times the spore length in the first 24. hours at 70 degrees F., 

 which becomes an indefinitely large mass of mycelium in two 

 days: At 38 degrees F., the groAvth is about one spore length the 

 first day, and 15 times this in five days. 



