| 
June, 1955 
INOCULA IN NATURE 
Sources of Data 
A total of 629 mycelial mats of Endo- 
conidiophora fagacearum were found be- 
neath the bark of 27 of the 30 wilt-killed 
oaks that were thoroughly studied over a 
10-month period, table 10. The remain- 
ing 3 trees, 1 standing white oak, 1 stand- 
ing bur oak, and 1 felled black oak, did 
not produce mats. “Twenty additional 
mats were taken from 4 red oaks that 
were examined only once and that were 
not included among the thoroughly stud- 
ied trees. These 20 mats brought the total 
number of mats found on 31 mat-bearing 
trees to 649. The figure for mats includes 
only typical mats with central pads accom- 
panied by cracks in the bark. 
The detailed data presented on the fol- 
lowing pages were obtained from 365, or 
56 per cent, of the total number of mats 
found. Forty-three of these mats were 
left on the trees, where each was resam- 
pled at 2-week intervals until it reached a 
deteriorated condition. The total number 
of additional samplings* that were made 
of the 43 mats on the trees was 100. 
Thus, the data came from 465 samplings 
of 365 mats, table 15. As each additional 
sampling of a mat was made at a later 
* A sampling involved taking three mycelial disks each 
7 mm. in diameter from a mat, as described on page 284. 
Curt: Oak Witt INocuLA 
311 
time than the one preceding and when the 
mat was more advanced in its develop- 
ment or decline, the data obtained from 
this sampling were treated as if taken 
from a separate mat. The figures in table 
15 represent mats sampled in all five study 
areas. More samples were taken during 
the spring and summer than at other pe- 
riods of the year, because more mats were 
produced at that time. Also, more mats of 
classes IV and V than of other classes 
were sampled, as they were found more 
often than mats of the other classes. 
Availability of Conidia 
The data regarding numbers and ger- 
minability of conidia obtained from sam- 
ples of naturally occurring mycelial mats 
of the oak wilt fungus in their different 
stages of development and decline during 
10 months are presented in table 16. The 
method of counting and _ germinating 
conidia is described in another section, 
“Treatment of Samples From Nature,” 
page 296. 
The average number of conidia per 
mat, as determined from mats of all 
classes, increased from October to Decem- 
ber, 1952, at which time the highest con- 
centration of the 10-month period was 
reached, fig. 19. The concentration of 
conidia then decreased steadily during a 
period of low winter and spring tempera- 
Table 15.—Numbers of samplings and average sizes (cm.) of mycelial mats of Endoconidio- 
phora fagacearum in five condition classes* sampled in the 10-month period October, 1952, 
through July, 1953. 
| 
Crass I Crass II Crass III | Crass IV CirassV | , 
| & 
cn ica) 
pomeeger i peel LE. ee ysl 8, 
| N 3 N BS N 3 N 5 N oF) sn 
Z. n Zz n Z 2) Z. a) Z ol < 
Wctober-.<...<. 5. - LETS e055 Deli 5 1 Sian oes 9x3 ioe sys Wl the lst! 
November......... Aaa Obs Sale 4a lope |) Talal SexiGu| Be Dix 423) | Oe 190) 1) (Osa4. 
December..........| 1 (eal Gale liexiou ele ix S 1 6x3] 0 _ 9|10x5 
enuaryes. "3. hat yall th ve allay lls eS) eal Dix 5) || LO xaG lene Dei lesciGulielu7a lellexs5 
Bebruary.......-:... Guilaexta ee Oxon 1On 20x: 6 19S xc 5 i 4254415 x65 
March... 21 Texan IPS xeoml On le Slee SW lee Saleh ial ox Gelso) LOX 5 
A\ Dial ee ae rae eae LOR iboats at txcGn Sel Soxe7 IDS Osta 3) Obes 1660) TDi 5 
Eh See eee ean LS al Six Onl On el Gres SON PLOeK Oui Soe) 2le xf) ed Sule 2oise 7 LOSS 20x16 
TE a nee A VAS Se Sule ba x Sol 12! | DS sc S) LA! Wi seG 1$5 1°23 x 8 1 90.| 20: %.7 
July... 0 — Dale) aon een | Dexa Sale ek WellGexaS kOe lei De Sel sl Sell) 1S 
Tie Se pe wene 72 _- 63 — 80 — 123 — |127 — (465 = 
*Condition class I, immature; II, mature; III, aging; IV, declining; V, deteriorating. 
