192 EXPERIMENTAL FARMS 



3-4 EDWARD VII., A. 190+ 



pound derived from tlie conoiHiiation of the sal soda and the white arsenic is arsenite 

 of soda. In the presence of lime this breaks down and arsenite of lime is formed. It 

 requires 4'4 pounds of crystal sal soda, or 1"6 pounds of dry sal soda to combine with 

 one pound of arsenic, and 2 pounds of freshly slaked lime to combine with one pound 

 of arsenic to form arsenite of lime. It is always desirable to have an excess of lime 

 present, in order to prevent all danger of burning; furthermore this excess is a con- 

 venience to fruit growers, because they can see by the distribution and amount of 

 lime on the foliage how well the spraying has been done. The formula, which is the 

 Kedzie formula with a few minor changes, has been used in many different sections 

 of the country with unvarying success. In all of the practical tests under the advice 

 of the writer, this solution is used and is found to be, not only as efficient as other 

 solutions, but far che:.per.' 



'When it is desired to rise Bordeaux mixture with this solution, it is added to 

 the Bordeaux mixture in the same proportion as to a similar quantity of water,' 



The above quotation is given here because I am aware that many fruit growers 

 in different parts of Canada are using white arsenic in some form for spraying fruit 

 trees in preference to Paris green, and moreover because considerable injury has fol- 

 lowed this practice, which has to a certain measure served to discredit the most im- 

 portant practice of spraying fruit trees for the prevention of injury by leaf-eating 

 insects. In my own experience, I prefer to use Paris green, knowing it to be perfectly 

 , effective and believing that, notwithstanding the fact that it i^ a littlj more expen- 

 sive than some other arsenical insecticides, it yet repays enormously any expenditure 

 by the improved condition of sprayed trees ; but, if other substances are used, probably 

 the Kedzie mixture is the best. Disparene, or arsenate of lead, is also another very 

 valuable insecticide, one great feature in its favour being the length of time it re- 

 mains effective on the foliage. Mr. Joseph Tweddle, of Fruitland, Ont., who not only 

 himself grows very satisfactory crops in orchards which he has sprayed, but has ako 

 done much work in spraying orchards for other fruit growers, who have beni well 

 satisfied with the treatment used by Mr. Tweddle, tells me that the spray which he 

 uses is made as follows :— ' I l=oil half a pound of vdiite arsenic in one gallon of water 

 with one pound of lime for 45 minutes, and make up to the original quantity of water 

 when it is finished boiling. I use this in 50 gallons of Bordeaux mixture for apple 

 and pear trees, except for the third or fourth treatment when it will sometimes burn 

 tlie foliage if used at this strength. I have never uscrl it on plums and cherries at 

 the above strength without doing some injury, and would always advise care in spray- 

 ing so as not to drench the trees. I find this mixture very effective against all leaf- 

 eating insects. When spraying peach trees for Curculio I use this mixture of half the 

 strength without the Bordeaux mixture, and when with the latter not more than one 

 quarter strength.' 



Prof. G. P. Gillette, of Colorado, recommends a somewhat simpler method of pre- 

 paring arsenate of lime, which is to boil for thrfee-quarters of an hour one pound of 

 white arsenic and two pounds of fresh lime in one gallon of water, and of this he uses 

 one quart to an ordinary barrel of 40 gallons. Prof. Gillette also draws particular 

 attention to the necessity of using fresh lump lime and of exercising the greatest cnre 

 in labelling everything containing this mixture plainly 'Poison.' 



Tlie proportior.s in which I have found the best known arsenical poisons satisfac- 

 tory, are as follows : 



Paris green — 1 pound to 160 gallons of water, with 1 pound fresh lime. 



Arsenate of lead— IJ pounds to 50 gallons of water. 



Green arsenoid — 1 pound to 160 gallons water, with 1 pound fresh lime. 



