The Canadian Horticulturist. 



131 



SPRAYING IN 1893. 



T seems hardly necessary, in the present year of 

 grace, that anyone should write in defence of 

 spraying, but Mr. Graham's communication on page 47 

 shows at least that the subject has not yet been sifted to 

 the bottom. His poor success was, however, probably 

 due rather to faulty methods than false inspiration, but 

 I must admit it is hard to see where the fault came in. 

 It is almost certain, however, that it was either in the Paris green 

 or the Bordeaux mixture. If the lime in the mixture were insufficient to convert 

 all the copper into hydrate of copper, either from lack of quality or quantity, the 

 copper sulphate would burn the leaves, and by that means might kill the tree. 

 On the other hand, if the Paris green were of an inferior and possibly more sol- 

 uble variety, the damage would be explainable in that way ; or, perhaps — and 

 here may lie a source of great danger in the use of Bordeaux — it may be that 

 the Paris green is dissolved by standing even a short length of time in the limy 

 mixture. It is well known that alkalies dissolve arsenic with tolerable readiness, 

 and it is probable, though I do not know positively, that a mild alkali like lime 

 may do the same thing, and if there is any considerable chance of that happen- 

 ing, it will be a bar to the use of Bordeaux that will suit some people very well, 

 as it is the dirtiest and most inconvenient and disagreeable method for the use 

 of copper as a fungicide. Some day we may use a plain solution of a copper 

 salt used with equally good effect, and in fact statements of success have been 

 written by people who have used sulphate of copper alone, but so far as I know 

 none of the Experiment Stations have followed the matter up. I have used 

 copper in ammoniacal solution with the best results, even with the admixture of 

 Paris green (which does not at all agree with my theorizing above !) and while I 

 have lost a few plums by curculio, I have had to thin out about one-third to one- 

 half of the remainder by hand on the best trees. There is no doubt that the 

 use of Paris green with ammonia may be dangerous, but by means of consider- 

 able care I have never had any untoward results. The poison has always been 

 added just at the moment of use ; and by using not too great an excess of am- 

 monia, and delivering a fine spray, I do not think any ammonia whatever reaches 

 the leaves in the spray, and the results have been the best. 



Mr. (iraham makes a good point in using Paris green for the first spraying 

 on gooseberries and currants. It is more easily applied and probably more 

 effective than hellebore. It reminds me of an experience which is noted in my 

 gardening record : — 



On May 21, '91, "Syringed bushes with hellebore; this should have been 

 done on 14th; some branches are stripped nearly clean." On May 17, '92, 

 " Put Paris green on currants and gooseberries, tho' no insects visible yet," and 



