Wormald.- — ‘ Brown Rot ’ Diseases of Fruit Trees . 379 
bark, so that although the stalk had become almost severed at the point of 
its insertion on the fruiting axis, being connected only with a narrow strand 
of fibrous tissue, the apple still remained in situ . 
Of the apples found on the ground those inoculated with M. fructi- 
gena were by this time almost entirely covered with yellow pulverulent 
pustules, while on those inoculated with M. cinerea the pustules were few 
and small or absent altogether. Most of the apples used as controls were 
still on the tree. 
Experiment 6. 
Monilia fructigena , when growing in stored apples, frequently causes 
a ‘ Black Rot ’ similar in appearance to that produced on those apples 
artificially inoculated with M. cinerea f. mali. Spinks (1915), investigating 
a ‘ Black Rot ’ of cider apples, found that ‘ the apples of the same variety 
showed the same type of rot irrespective of the fungus with which they 
were infected ’, and that ‘ it seemed certain that the type of rot produced in 
an apple by Monilia fructigena depended only on the apple itself ’. 
An experiment carried out at Wye in 1916 shows that this is not invariably 
the case, as seen by the results here recorded. 
Strains used 
'Monilia fructigena , strain from a plum. 
Monilia fructigena , strain from a ‘ Black Apple ’. 
Four apples (variety Bramley’s Seedling) were each inoculated on one 
side with a strain isolated from a pustule of M. fructigena growing on 
a plum, and on the other side with a strain isolated from the fleshy tissue 
of an apple affected with ‘ Black Rot ’ ; the inoculations were made on 
September 8. 
Result. 
Side inoculated with Plum strain. 
Side inoadated with 1 Black Apple ’ 
strain. 
September 13. 
A brown discoloration extended 
from point of inoculation for 2.5- 
3 cm. ; pustules from 60 to 90 in 
number. The discoloration was 
a uniform brown, no dark circles at 
the lenticels. 
Discoloration extended 2*5-3 cm. 
from point of inoculation ; the 
pustules on the four apples numbered 
respectively 1, 4, 2, and 13. The 
discoloration was darkest towards 
centre of affected area, shading off 
to a brown of the same tint as that 
on side infected with the plum 
strain ; dark brown circles round 
lenticels. 
September 18. 
The whole side was now a uniform 
brown ; no black circles at lenti- 
cels ; pustules numerous. 
Brown colour still darker round 
point of inoculation ; pustules few 
and scattered; black circles round 
the lenticels. 
October 12. 
Pustules numerous, in an almost 
continuous layer, but showing some 
tendency to form concentric circles 
round the centre of infection; the 
skin, where it could be seen between 
the pustules, was dark brown to 
black, 
Pustules few and scattered ; skin 
dark brown to black, nigrescence 
most conspicuous immediately round 
the lenticels. 
