no Injury to Foliage by Bordeaux Mixture, [may, 



In connection with this important subject of injury follow- 

 ing the application of properly-made Bordeaux mixture, i.e. 

 the occurrence of true "Bordeaux injury," it is necessary to 

 emphasise the fact that caution is required in its investiga- 

 tion. The presence of injury (even though it be indistin- 

 guishable from true "Bordeaux injury") on sprayed trees 

 must not be considered as evidence of the injurious action of 

 the spray, unless "control" trees which have been left 

 unsprayed show no such injury. Further, there are many 

 causes at work — some of which are controllable, while others 

 are not, — which produce injuries often exactly similar to 

 "Bordeaux injury." Such injuries are being constantly 

 confused with "Bordeaux injury." 



In the first place, unless care has been taken to use only 

 freshly-burnt quicklime (in lumps) in the making of Bor- 

 deaux mixture, a scorching of the leaves will certainly follow. 

 The use by fruit-growers of mixtures made with partly air- 

 slaked lime is unfortunately of common occurrence; such 

 mixtures undoubtedly cause serious injury to foliage and 

 fruit. Again, leaves already attacked by fungi will, when 

 sprayed with Bordeaux mixture, show very pronounced 

 injury. For instance, if leaves of an apple tree which are 

 already covered with the "sooty" patches of the "scab" 

 fungus (as shown in this Journal for June, 1908, Vol. XV., 

 Figs. 2, 3, 4) are sprayed with properly-made Bordeaux 

 mixture the portion of the leaf covered by the fungus will 

 turn brown or blackish and soon die, or if the whole leaf is 

 infected by the spawn (mycelium) of the fungus, it will 

 become discoloured and will shrivel up. It is important for 

 the grower to remember that he must get the Bordeaux 

 mixture on to the leaves as early as possible each season, 

 that is, before the fungus has spread to them. 



But the commonest form of injury confused with "Bor- 

 deaux injury" is that caused by unfavourable weather 

 conditions. Exactly what these weather conditions are is 

 unknown. During the seasons 1908 and 1909 I have seen 

 a considerable number of specimens of young apples (sent 

 to me from districts in Kent, Surrey, Worcestershire, and 

 Herefordshire) which were split or deeply cracked, and often 

 more or less "rusty" or "russeted." These apples, which 



