W or maid. — ‘ Brown Rot ’ Diseases of Fruit Trees. 3 77 
parison the American form of M. cinerea and a £ Black Apple ’ strain of 
M. fructigena. 
The apples were inoculated on October 26. ‘ Brown Rot ’ soon 
appeared in all of them except ^one of those inoculated with the £ Black 
Apple * strain of M. fructigetia , and as, with this exception (in which 
infection failed), the results obtained in any one series were approximately 
uniform, they are described in the table in general terms. 
Strain of Monilia. 
M. cinerea 
f. malt. 
M. cinerea 
f. prnni. 
M. cinerea 
f. americana. 
Result. 
Nov. 3. 
The rot had extended 2. 8-4*0 cm. 
from point of inoculation ; pustules 
absent; distinct but irregular dark 
brown zone at 1 -5-2.5 cm. from the 
wound. 
Extension of rot 2. 2-3-5 cm. ; 
numerous grey pustules on one 
apple and a few on the others. 
Extension of rot 2.0-3. o cm. ; 
discoloration brown, with a darker 
zone at o^-i-o cm. from wound; 
pustules few, small (about 1 mm. 
diam.), and grey. 
Nov. 30. 
One apple quite black, the other 
two black over nearly the whole 
surface, the remaining portion being 
dark brown ; pustules minute, few 
in number ; skin very slightly 
wrinkled. 
Surface of all three a bright brown ; 
no nigrescence except for a few 
millimetres immediately round the 
wound ; numerous grey pustules 
about 1 mm. diam. ; skin much 
shrunken and wrinkled, particularly 
w-here the pustules were closely 
aggregated. 
All three quite black with the 
exception of a small brown patch on 
one of them ; pustules few, small, 
grey ; skin slightly wrinkled. 
M. fructigena. 
Strain from apple 
spur. 
Extension of rot 1.8-2. 5 cm.; 
pustules absent ; discoloration 
brown, with a narrow peripheral 
zone a little darker. 
All three brown to dark brown ; 
pustules yellow, to 3 mm. diam., 
very numerous ; surface of apples 
much shrunken and wrinkled. 
M. fructigena. 
Strain from a ‘Black 
Apple ’. 
Extension of rot 1.5-2. 7 cm.; 
pustules absent ; discoloration 
brown, with a narrow peripheral 
zone a little darker. 
All three brown to dark brown ; 
pustules yellow, to 3 mm. diam., 
very numerous ; surface of apples 
much shrunken and wrinkled. 
Strains used 
Experiment 4. 
Monilia cinerea forma mali. 
Monilia fructigena , strain from an apple spur. 
On July 6, j 9 1 7, six apples (var. James Grieve), growing in the open, 
were inoculated with M. cinerea and eight with M. fructigena ; a number 
of apples wounded but not inoculated served as controls. In each series 
infection failed in two of the apples. Those which became infected had 
all fallen by July 20, so that it was decided to repeat the experiment, 
and other apples were inoculated with the same strains on July 254, as 
described under Experiment 5. The results obtained to July 20 are to 
be noted, however, for comparison with those recorded in the next 
experiment. 
