FT. W()R>[ALl) 



53 



May 2(] 



-Yo. 2. The styles of one 'iowor were brown 



almost to the base; in tlie otlier (lower the 



styles were ])rown tliroiighout their whole 



length 



No. 3. All styles of the three flowers brown 



to base; stamens upright 

 No. 4. Styles of both flowers brown to base; 

 stamens npright. Uninoenlatcd flowers 

 had, in general, brown stigmas only but in 

 some the discoloration extended half-way 

 down the styles; no drooping stamens 

 observed 



(CO///.) 



No. 2. Flower with stamens collapsed, calyx 

 lobes withering, leaves round base of 

 umbel beginning to wilt 



No. .3. Stamens collapsed; caly.x lobes 

 withering; leaves show a slight wilting 



No. 4. Stamens eollap.sed, but no wilting of 

 leaves noticeable. Control flowers of the 

 same age in the vicinity had styles brown 

 for about half their length, there was no 

 withering of caly.x lobes and the stamens 

 weje all upright 



May 29 



No. 1. Two of the flowers had fallen away, 

 the third had remained apparently un- 

 changed since the 26th 



No. 2. Styles brown to base, and in one 

 flower the calyx lobes were withered 



No. 3. No further change noticeable except 

 that in one flower the stamens were droop- 

 ing 



iVo. 4. No further change noticeable. Many 

 of the control flowers by this time had 

 styles brown to base; stamens generally 

 upright; calyx lobes not withered 



June 6 



There was no wilting of the leaves on any of 

 the four spurs; the inoculated flowers had 

 all failed to set into fruit, they had be- 

 come withered and fallen ojf; of the un- 

 inooulated flowers some were setting into 

 fruit : 



No. 1. One flower setting into fruit 



No. 2. None setting 



No. 3. Two flowers setting 



No. 4. Two flowers setting 



The young fruit on these spurs were 1-1-5 

 cm. in length 



In all four the infection hail by this date 

 extended from the inoculated flower into 

 the tissues of the spur as shown by the 

 fact that in each case the leaves round the 

 1 ase of the umbel of flowers showed a 

 distinct wilting, were turning brown and 

 their margins were more or less curved 

 inward 



June 4 



All the flowers (those untreated as well as 

 those inoculated) and the leaves of the 

 four spurs were cjuite withered; the dead 

 flowers remained in position on the spurs, 

 this condition being typical of the "Blos- 

 som Wilt" disease of the apple tree 



No. 4 was removed and mycelium was 

 found in the tissues of the spur 



June 7 

 The other three .spurs were removed and cut 

 longitudinally; in each ca.se the young 

 growth of the spur (bearing the leaves and 

 flowers) was Cjuite brown throughout and 

 the browning had extended along the 

 bark of the older portion for a distance 

 of about 3 cm. 



(e) Deductions from Results of Inoculation Experiments. 



The experiments show that the particular strain of Monilia cinerea 

 obtained from the plum twig is less virulent as a parasite on the apple 

 than the apple blossom strain itself since it was unable to establish itself 

 in the spurs of the trees inoculated, and this in spite of the fact that the 

 method of inoculation adopted favoured the "Wither Tip" strain; thus 

 in the second experiment ten flowers were inoculated with this strain as 



