1910.] Injury to Foliage by Bordeaux Mixture. hi 



were about a quarter grown, were supposed by the growers 

 in some cases to be affected by the "scab " fungus; in other 

 cases they were believed to be affected by "spray injury," 

 Investigation showed that no fungus was present, and also 

 that this injury occurred on sprayed and unsprayed trees 

 alike. It seems that under certain unfavourable weather 

 conditions — perhaps cold nights — soft-fleshed apples, such 

 as Beauty of Bath, are liable to this injury. 



During the past season two forms of injury to the 

 leaves of the apple, due to unfavourable climatic condi- 

 tions — possibly an excessive rainfall or, in some dis- 

 tricts, low temperatures at night and cutting winds — have 

 been much in evidence. The injury has consisted in 

 (i) the whole leaf turning brownish and falling from the tree ; 

 or (2) the edges, or occasionally the tip, of the leaf, turning 

 brown and curling or shrivelling, giving the whole tree (or 

 sometimes only a branch or two of it) the appearance of having 

 been badly scorched by a dangerous spray, or, where the injury 

 was very severe, of having been injured by a fire lighted in 

 its neighbourhood. In several instances this injury has been 

 ascribed erroneously to the after-effect of Bordeaux mixture. 

 In two cases where this kind of injury was very pronounced, 

 investigation showed clearly that "weather conditions" alone 

 were the cause. 



In the first of these cases the plantation concerned 

 was at Wye College; here the "scorched" appearance 

 of many rows of apple trees was very noticeable last 

 summer. Had the whole of such a plantation been sprayed 

 with Bordeaux mixture, and no "controls" left, the con- 

 clusion would inevitably have been drawn by the practical man 

 that the injury was due to the spraying. As it so happened, 

 only 441 trees out of the 1,500 trees in this plantation had 

 been sprayed. Consequently it was possible to compare 

 sprayed with unsprayed trees. The facts were as follows : — 

 The following eleven varieties were sprayed a few weeks after 

 blossoming : Wellington, Bismarck, Duchess' Favourite, 

 Warner's King, Newton Wonder, Cox's Orange Pippin, 

 Blenheim, Stirling Castle, Ecklinville, Cornish Gilliflower, 

 and Twenty Ounce. Some trees of Wellington and' 

 Cox's Orange Pippin, and all the trees of Blenheim and 



