318 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



result of spraying depends on the form in which we put the spray on 

 the leaf. I am now confining myself, as Mr. Massee did, to spraying 

 for fungus diseases ; and I should say that the photograph which is 

 shown of a well- sprayed leaf is not what we should aim at. We can 

 get nozzles now which throw a spray so fine that if you photograph the 

 leaf there is practically nothing of the mixture to photograph, because it 

 is sprayed over so finely that it is left in the form of an almost impalpable 

 dust. The Bordeaux mixture put on with a proper nozzle is as evenly 

 distributed over the leaf as dust is by the roadside. I think this is a very 

 important point indeed, and I want to impress upon growers the fact 

 that when they are spraying they must aim at that appearance of the 

 Bordeaux mixture on the leaf — no large spots, but a kind of powder. 

 The spraying machinery and the nozzles are as important as the spray 

 itself. 



Mr. Massee mentioned that he had noticed the spores of fungus 

 germinating on spots of Bordeaux mixture. Of course there is no reason 

 why the spores should not germinate on any surface. But the whole 

 point is, whether the germ tubes of those spores would be able to penetrate 

 into the leaf on the spots of Bordeaux mixture, or whether they would 

 not be able to do so. The mere fact that spores are able to germinate 

 on Bordeaux mixture must not be used as an argument against the 

 value of Bordeaux mixture. Then also the fact that a scab of apple 

 covered over with Bordeaux mixture will go on extending, must not be 

 used as an argument against the efficacy of Bordeaux mixture, because, 

 as Mr. Massee himself said later on, Bordeaux mixture must be looked on 

 as a preventive. It should be on the parts before the fungus is about. I 

 think it is very important not to allow any arguments to be put forward 

 against Bordeaux mixture without examining them closely ; for we must 

 remember that Bordeaux mixture, after all, is the best fungicide yet 

 invented ; it has its faults and it is not perfect, as we know. You get 

 forms of injury such as scorching or the shot-hole appearance of the 

 leaves and a yellowing of the leaves. You get all these things, but still 

 we have in the Bordeaux mixture the nearest approach to the perfect 

 fungicide. Notes are sometimes given as to the ill effects of Bordeaux 

 mixture by growers, but it is very necessary indeed to look into them 

 carefully before we accept the injury as due to the Bordeaux mixture. 

 I will mention one such case which came under my notice. It is con- 

 stantly said that when leaves of Cox's orange pippin are sprayed with 

 Bordeaux mixture they fall off. In many cases, but not in all, there 

 were no control plants of Cox's orange pippin standing by which had not 

 been sprayed ; and in many of those cases I feel sure that if there had 

 been some controls it would have been seen that the leaves had also 

 fallen from the control trees. I have repeatedly found in the plantation 

 at Wye College that the foliage was so tender that fungus got on 

 to it and the tree became defoliated, whether the leaves were sprayed 

 or not. Iam very glad indeed that Mr. Massee emphasizes the importance 

 of the grower making his own fungicide, especially Bordeaux mixture. 

 We can only hope to get good results from Bordeaux mixture by the 

 grower making it himself. There is not time now to go into the details 

 of why this is so ; but I want to express my entire agreement with 



