376 Wormald. — ‘ Brown Rot ’ Diseases of Fruit Trees. 
Result. 
Apple No. i on side inocu- 
lated with M. cinerea forma 
mali. 
Apple No. i on side inocu- 
lated with M. cinerea forma 
pruni. 
Apple No. 2 on side inocu- 
lated with M. cinerea forma 
mali. 
Apple No. 2 on side inocu- 
lated with M. cinerea forma 
pruni. 
Sept. 2i. 
Discoloration extending 4-4-5 
cm. from inoculated wound, 
dark brown in zones, no pus- 
tules present, conidiophores 
along cut 
Discoloration extending 2-5-3 
cm., from wound, bright brown 
with a slightly darker margin ; 
a few minute scattered pustules. 
Discoloration extending 4-6 
cm. dark brown in zones ; 
a few small scattered papillae ; 
conidiophores along cut. 
Discoloration extending 1.5-3 
cm. from wound ; many small 
pustules present and conidio- 
phores along the cut. 
Oct. 12. 
A little more than half the 
surface of the apple black , not 
shrunken ; no pustules, but a 
few small barren papillae 
present. 
This side (rather less than half 
surface') brown and distinctly 
marked off from the black 
portion ; not shrunken ; no 
powdery pustules, but numerous 
papillae present. 
As in Apple No. 1. 
Numerous small grey pul- 
verulent pustules present ; skin 
distinctly shrunken and 
wrinkled, brown. 
October 25 . No further definite change in any of the apples except 
that the shrinkage is a little more pronounced. 
The two strains used in this experiment were the same as those used 
in the inoculation of apple flowers as described in the paper on ‘ A Wither 
Tip of Plum Trees’ (1918); in that paper it was shown that the Wither 
Tip strain failed to induce the typical ‘ Blossom Wilt ’ condition on an 
apple tree, while on the same tree inflorescences inoculated with the Blossom 
Wilt strain quickly succumbed. In the case of these two strains the degree 
of the virulence of their parasitism on apple flowers is associated with 
differences in their physiological relations with the host tissues when 
growing on the fruit of the apple tree. 
Experiment 3. 
1 Monilia cinerea forma mali. 
Monilia cinerea forma pruni. 
Strains used- Monilia cinerea forma americana. 
1 Monilia fructigena, strain from an apple spur. 
' Monilia fructigena , strain from a f Black Apple’. 
Fifteen apples (all of one variety, viz. Bramley’s Seedling) were selected 
as being free from blemishes, divided into groups of three, and the groups 
respectively inoculated with the five strains of Monilia . The strains of the 
forms mali and pruni of M. cinerea were the same as those used in 
Experiment 2 , and the strain of M. fructigena obtained from an apple 
spur was that used in Experiment 1 . The present experiment, therefore, 
served as a duplicate of the previous ones, and also introduced for com- 
