CONFERENCE ON SPRAYING- OF FRUIT TREES. 



321 



or sodium carbonate has the disadvantage of giving sodium sulphate 

 as a by-product, and sodium sulphate is admittedly highly injurious 

 to vegetation. In order to get over that — as an experiment — during 

 the last year or two I have used with very great advantage potassium 

 carbonate, which is, of course, dearer ; but the resulting product 

 is sulphate of potash, which is a valuable substance for potatos. The 

 potatos I have had raised in the last few weeks have been greatly 

 benefited, whereas the ordinary crop would be a very poor one. I have 

 poor cultivated land, which is assessed at 5s. an acre, and I have had 

 this season 14 tons 13 cwt. to the acre. That is on land said to be 

 some of the poorest in the kingdom, and the result was obtained by the 

 aid, to some extent, of modified Bordeaux mixture made with potassium 

 carbonate instead of sodium carbonate or quicklime, and there was almost 

 no disease. 



While dealing with the spraying substance Mr. Massee and, to some 

 extent, Mr. Salmon have referred to the importance of completely cover- 

 ing the leaf. Now is it not a fact that if small quantities of Bordeaux 

 mixture are thrown on the leaf in what we may term a weak form of 

 spray that substance remains on the leaf in a difficultly soluble form — 

 it is for the most part insoluble — but the conditions which enable the 

 spore to germinate take effect when the weather is damp. Surely the 

 conditions which are essential for the germination of the spore are the 

 very conditions which are also essential for the bringing into solution of 

 a very minute quantity of the basic sulphate of copper, which is really the 

 result of the application of the Bordeaux mixture, so that I maintain it 

 is not necessary to clothe the leaf, as it were, with a mackintosh and to 

 thereby almost prevent assimilation. But the small amount of material 

 put on with the best apparatus, even if it does not completely cover the 

 leaf, will yet act as an effective preventive against the various fungus 

 pests. I might also say that in the last few years, inasmuch as nearly all 

 our fungicides, especially Bordeaux mixture, are so insoluble, in order to 

 make it more penetrating I have with very considerable success added 

 ammonia. The result of adding ammonia will be to dissolve the copper 

 compounds ; and there is no doubt whatever that it is far more penetrat- 

 ing and far more effective in reaching the under surface of the leaf, which, 

 as Mr. Massee told us, is somewhat difficult to do. 



Mr. Percy Bunyakd : In regard to petroleum and paraffin, so far as 

 my experience goes, they are absolutely out-of-date, and I will tell you 

 why. The very fact of their being of an oily nature is conclusive that 

 they are not sufficiently penetrative. I was very glad indeed to hear 

 Mr. Getting mention nicotine. Nicotine is a most penetrating insecticide. 

 Nicotine from its very nature, being a vegetable alkaloid, will get 

 into those parts which oil and paraffin emulsions cannot possibly 

 penetrate. I should like to hear Mr. Massee's opinion in regard to 

 nicotine, and I should very much like to know if he has ever experimented 

 with it. 



With regard to spraying machines and nozzles I must agree with the 

 remarks of our lecturers, that at present we have nothing which makes 

 quite such a fine spray as London fog, and I doubt very much, if anything 

 did make such a fine spray whether it would reach the underside of the 



VOL. XXXIV. " Y 



