June, 1955 
the entire mat was estimated as being ap- 
proximately 378,000,000. Another mat 
which measured 24 by 10 cm., the pad 6 
by 2 cm., and which had the same average 
number of spores on a disk sample as the 
mat above, was estimated to have 1,650,- 
000,000 conidia, more than four times as 
many as the other mat. 
From these figures one can appreciate 
the significance of mat size as well as 
numbers of mats in accounting for the 
concentration of conidia in an oak wilt 
area. It can be seen in table 15, which 
gives the average sizes of all mats sampled 
in each month, that the mats of May and 
June were considerably larger than those 
of other months. The sizes of the mats 
sampled in all months ranged from 1 by 
1 cm. to 48 by 14 cm. 
As pointed out earlier, other possible 
Curt: Oak Witt INocuLA 
315 
mycelial sources of oak wilt inoculum 
might be afforded by the padless mycelial 
mats that form on bark pieces on the for- 
est floor and by wound-stimulated myce- 
lial growth on standing and felled trees. 
The conidial sporulation on such mats 
and the ability of the spores to germinate 
appear to be equal to those of typical mats 
with pads, table 18. 
Availability of Fertile Perithecia 
The total number of mats found with 
perithecia during the 10-month study pe- 
riod was 90, or 23 per cent of 393 mats 
studied in detail, table 19. Perithecia 
were never present on class I mats. The 
month with the highest percentage of 
perithecium-bearing mats was December 
and the next highest May. 
Table 18.—Average number and germinability of conidia of Endoconidiophora fagacearum 
obtained from wound-stimulated mycelial mats and from mats on bark pieces on the forest 
floor during 3 months of 1953. 
Wounpb-STIMULATED Mars Marts on Bark on GrRounD 
MontTH Average Per Cent Average Per Cent 
Number Number of Number Number of 
of Mats £ Candi of Mats f Con: 
Sampled oe eer Sampled melee Steal 
Conidia Viable Conidia Viable 
March 2 480,000 35 4 256,000 56 
aN oraI\5's OSes 16 279 ,000 34 13 38, 500 7 
LESTE 3 a a 6 72,000 9 — a — 
Table 19.—Perithecium-bearing mycelial mats of Eudoconidiophora fagacearum in four 
condition classes* found on wilt-killed oaks in the 10-month period October, 1952, through 
July, 1953. 
Crass II Crass III Crass IV Crass V 
i] 
Y Eos 
ONTH v 2 a as Zv a Z & =m) 
sae|e 2) 5228/5 Blese|s Bl) eeg|e 8) BEB 
a Sie 2s ra Se 24 OS's ous ames ous Olen = 
pee | ese | see | Ese | s=2| sae | cea | eet | 22 
Z6a | Zea |Z ou | Zee | Zou | Zea | 2 sai | zee | ase 
October....... 2 2 1 0 3 0 1 0 29 
November..... 4 1 1 0) 8 1 3 0 13 
December..... 6 3 1 1 1 0 0 0) 50 
Wanuary..... 6 0 1 1 5 4 2 0 36 
February...... 5 1 10 1 19 7 4 1 26 
March. 55... 12 0 12 0 25 2 il 7! 2 6 
April 11 1 11 2 12 1 13 0 9 
WEN ASR ee 10 3 30 21 33 18 23 0 44 
June 5 2 12 3 14 8 55 4 20 
Selva ns 3 Sk 2 0 1 0 3 0 9 0) 0 
*Condition class 
II, mature; III, aging; 
IV. declining; V, deteriorating. 
