June, 1955 
Curt: Oak WI tt INocULA 
287 
Table 3.—Germination of ascospores of Endoconidiophora fagacearum at various centi- 
grade temperatures on 2 per cent water agar. 
Per Cent GERMINATION aT DESIGNATED TEMPERATURE 
NuMBER i 
or Hours 
Ife 16° De DY 28° 31° 34° 
Oe oe eee 0 0 20 32 33 14 0) 
MAL, bec nn 0 3 44 47 49 38 0) 
33), 240 eae 0 20 61 63 68 58 3 
AE oh Oe EL 0) 36 = — 71 60 5 
1 a1 SRE ee i 54 — — 78 61 8 
30 6 Oke Eee 18 64 _ _ —- 61 10 
210). et ee 37 74 — — _- 68 12 
Table 4.—Germination of ascospores of Endoconidiophora fagacearum at various centi- 
grade temperatures on 2 per cent dextrose agar. 
Per Cent GERMINATION AT DESIGNATED TEMPERATURE 
NuMBER 
or Hours 
(& 16° phe DUS O86 Sie 34° 
108 gh ot eee ee 0 0 29 46 45 19 0 
DE Ae ee ee 0) 1 58 75 69 49 0 
big PRS eee ae ees 0 14 69 81 74 60 2 
OMAP, ince Cs 0 21 = — 79 73 4 
AD atts eee eee eee 9 53 i ~ 84 76 5 
GO ee ae 12 57 — — — 78 7 
(2X0) Aah ee e 23 70 i — a 87 8 
grown on chestnut agar (30 gm. chestnut 
meats and 20 gm. agar in | |. distilled 
water) were germinated in Petri dishes, 
some containing water agar and some 2 
per cent dextrose agar; each dish was 
subjected to one of seven incubation tem- 
peratures: 7, 16, 22, 25, 28, 31, and 34 
degrees. At most of the temperatures 
germination was slightly higher on dex- 
trose agar than on water agar, tables 3 
and 4 and figs. 5 and 6, the highest ger- 
mination for any single time interval oc- 
curring at 25 and 28 degrees. Secondary 
conidia started to form at about the same 
time for each temperature on both media. 
However, at an incubation temperature 
of 28 degrees, further production of co- 
nidia was retarded, so that at this tem- 
perature the counting of germinated asco- 
spores was not confused by germinated 
conidia until after 70 hours. At incuba- 
tion temperatures of 22 and 25 degrees, 
counts of ascospores became confused by 
germinated conidia after 36 hours. After 
120 hours, ascospores incubated at 31 de- 
grees had moderately long, unbranched 
germ tubes that did not sporulate, and 
spores incubated at 34 degrees had very 
short germ tubes that did not continue to 
grow. 
After these tests, it was concluded that 
a 2 per cent water agar medium and an 
incubation temperature of 28 degrees for 
36 hours would be best for determining 
germinability of both conidia and asco- 
spores of Endoconiodiophora fagacearum. 
Sampling 
It is recognized that a larger number 
of samples than the three mycelial disks 
that were taken from each mat at each 
sampling might have been desirable in 
obtaining samples that were representa- 
tive. However, as some mats were left on 
trees and sampled several times, the tak- 
ing of a much larger number of samples 
would have destroyed the smaller mats. 
A short test was run to find how great 
a difference might be expected between 
samples taken from different parts of a 
mat. Four immature (class I) mats were 
used in the test. Three disk samples (each 
7 mm. in diameter) were taken from each 
