390 Wormald. — ‘ Brown Rot ’ Diseases of Fruit Trees . 
Strain A a . — Obtained from the same spur as A 2 , but cultures started 
in March, 1918. 
Strain B. — From a naturally infected spur of a Lord Derby apple tree 
in the College plantation in April, 1918. 
Strain C. — From a dead plum twig in the College plantation, isolated 
March, 1918. 
Strain D. — From a mummied plum sent from Cambridgeshire, March, 
1918. 
Strain E. — From a mummied cherry sent from Mid-Kent, March, 1918. 
Strain F. — From a flower of Pyrus japonica from Mid-Kent, July, 
I 9 I 7 * 
The experiments were all carried out on apple trees of the James 
Grieve variety growing in the plantation. Spurs, each bearing an umbel of 
several flowers, were labelled and two flowers (a and b) in each umbel were 
inoculated. The situation of the inoculated flowers on the spur was noted 
so that a comparison could be made between inoculated and non-inoculated 
flowers on each umbel, the latter thus serving as controls during the early 
stages of infection. The inoculations were made as in the experiment on 
plum flowers, except that in the present case the conidia-bearing surface of 
the potato particles was brought in contact with the stigmas. 
Experiment i. 
fAj Apple Blossom Wilt strain, isolated 1916. 
Strains used jA 2 „ „ „ 1917. 
I.A 3 „ „ „ 1918. 
The inoculations were made on May 8, 1918, and the results to May 21 
are given in the accompanying table : 
Strain. Spur . 
£ 
May 14. 
May 18. 
May 21. 
$ 
A i 1 
a. 
Styles brown for 1-8 
All the flowers of the in- 
The whole inflores- 
mm. 
florescence dead ; leaves 
cence, together with 
at the base of the umbel 
leaves at base, was now 
b. 
Stigmas only brown. 
wilting. 
brown and dead; flowers 
recurved and leaves 
curled. 
2 
a. 
Styles brown to base. ' 
Ditto 
Ditto 
b. 
Ditto 
3 
a. 
Ditto 
Both inoculated flowers 
had brown withered 
Ditto 
b. 
Ditto 
stamens ; pedicels brown 
and wilting ; some of the 
leaves were wilting, but 
the non-inoculated flowers 
were upright. 
