J 921.] Wither-Tjp and Brown Rot of Plums. 1145 



Control Measures. — At present there are three methods of 

 treatment, as indicated below : — 



(a) Removal of affected fruits and mummies. — It cannot be 

 understood too clearly that new infections are mainly brought 

 about by the mummies hanging on the trees, and by diseased 

 twigs. Diseased and decayed plums should therefore be picked 

 and dropped to the ground at the same time as the crop is 

 gathered. Any mummies that are left on the tree should be 

 removed in winter before the buds swell. They should be col- 

 lected and burned or deeply buried. 



(b) Cutting out of diseased shoots. — As far as possible all dead 

 twigs bearing pustules should be cut out. and if the attack is not 

 extensive it will be possible to do this without excessive labour 

 or serious injury to the trees. If large areas are concerned the 

 labour is of course prohibitive, and the trees may be injured 

 through excessive cutting out. At the same time, it should be 

 remembered that the affected wood is quite dead, and therefore 

 useless. 



(c) Spraying. — In spraying the aim is to destroy the spore- 

 pustules on the wood by means of a caustic winter wash, but 

 the treatment is only in an experimental stage. The chief diffi- 

 culty is to wet the pustules thoroughly, as on account of their 

 powdery nature, the spraying fluid runs off. This can partly be 

 overcome by the addition of soft soap. The mixture which 

 has proved most promising is as follows : — 



1 lb. caustic soda. 

 1 lb. soft soap. 

 10 gal. water. 



The best time for applying a winter wash depends to some 

 extent upon the season. It should be applied as late as possible, 

 but not too late to run the risk of damaging the opening buds. 

 Generally speaking, the correct time is about the end of 

 February or the beginning of March, but in a cold, late season 

 the spraying might be delayed until the end of March. 



