ENpDOTHIA CANKER oF CHESTNUT 571 
that Metcalf and Collins probably had in mind the tunnels produced by 
the bast-miner, an undetermined species. 
Anderson and Babcock (191 3) and Rankin (1914) havé called attention 
to the fallacy of basing conclusions as to origin on the wounds found on a 
canker, since these are quite as likely to have followed as to have preceded 
the entfance of the parasite. These experimenters made a large number 
of inoculations in various kinds of wounds, imitating the wounds that 
are found naturally on the trees. Their results are given in Tables 1 and 2: 
TABLE 1. CoMPARATIVE VALUE OF DIFFERENT KINDS OF Wounps FOR INFECTION. 
CHARTER OAK, PENNSYLVANIA 
Number of 
Character of wound ‘Inoculum inocula-_ | Petcentage 
tions successful 
Longitudinal slit.............. Diseased bark.............. 568 93.6 
Longitudinal slit.....,........ Mycelium from culture...... 454 89.2 
Diagonal slit............0.... Mycelium from culture...... 25 96.0 
Diagonal slit................. Dry spore horns............ 16 93.7 
V-shaped cuts................ Conidia in water........... 97 93.8 
V-shaped cuts..............0. Ascospores in water......... 88 94.3 
V-shaped cuts..............., Ascospores shot in dry...... 1,228 82.5 
Artificial borer holes.......... Mycelium from culture...... 68 54-4 
Natural insect holes........... Mycelium from culture...... 18 0.0 
Natural insect holes........... Conidia in water........... 23 0.0 
Natural insect holes........... Ascospores in water......... 22 0.0 
Peeling down bark............ Mycelium from culture...... 25 88.0 
Stab with knife............... Ascospores in water......... 347 | 36.9 
Stab with knife...... AEG AS Conidia in water........... 81 86.8 
Stab with knife............... Dry spore horns............ 96 79.1 
Scraping off outer cork layer..| Mycelium from culture...... 25 0.0 
Cut StHbS)s sc aak accdacive pues oan Mycelium from culture...... 22 81.8 
Broken branches.............| Mycelium from culture...... 45 71.9 
Natural cracks............... Mycelium from culture...... 25 0.0 
Gimlet holes....... ea sasiaea nt ae Ascospores in water......... 135 52.6 
Hypodermic needle........... Ascospores in water......... 54 75.9 
TABLE 2. Resutts oF INOCULATIONS MADE IN WOUNDS FROM May 1 TO SEPTEMBER 
I, 1913, AT Napanocu, NEw YorK 
Average 
Number | Number | Percentage t 
Meee aa made infected jof infection Leena 
Ascospores in water.... 89 88 99 
Conidia mae ee I a 95 82 
ted Mycelium from culture. I I 100 
Slits in bark. Diseased bark......... 93 93 100 92 
Conidia dry........... 10 10 100, 
Pycnidia from wood. . 11 4 36 
att Ascospores..........- 107 74 69 
Injections. .. { Conidia iene oe 56 46 82 \ 74 
Saw wounds.| Diseased bark......... 50 26 52 “52 
