NEW YORK EXPERIMENT STATION BULLETINS. 



367 



Dates of 



applica- 

 tions. 



July 11 



" 27 



Aug. 10 



" 20 



Plants used. 



July 23. Aug. 8. Aug. 22. Sept. 5 



Apple (Mcintosh Red) 



Pear (Clapp).. 



Quince (Meech) 



Peach (Craioford) 



Grape (Geneva) 



Egg-plant 



Potato (June Eating) 



Dates of application and per cent, 

 of Injury. 



Although these two combinations are little more than one half as strong 

 as Nos. 1 and 2, still the amount of injury done is about as great. The 

 most remarkable difference between these two tables appears in the case of 

 the apple. No. 7. injured 50 per cent, of the foliage of Seek-no-further, 

 while only 5 per cent, of the foliage of Mcintosh Red was injured by 

 No. 8. All of this difference can scarcely be due to the difference in the 

 combinations applied ; it is undobtedly owing to the fact that one variety 

 can better withstand the injurious action of the combinations than the 

 other. The difference between the quinces is not so great, but the Paris 

 green combinations again injured the trees more than that containing 

 London purple. 



No. 9. Carbonate of copper in suspension in water, 3 ounces to 22 gallons 

 of water. Paris green at the rate of 1 pound to 200 gallons of water. 



No. 10. Carbonate of copper as in No. 9. London purple 1 pound in 

 200 gallons of water. 



No. 11. Carbonate of copper in suspension, 1^ ounces in 22 gallons of 

 water. Paris green at the rate of 1 pound in 200 gallons of water. 



No. 12. Carbonate of copper as in No. 11. London purple 1 pound in 

 200 gallons of water. 



These combinations also injured the foliage considerably. The Mcintosh 

 Red apple and the Clapp pear were uninjured by No. 9; 30 per cent, of the 

 foliage of the same variety of apple was injured by No. 10. The injury to 

 the pear foliage averages about 7 per cent, for the four combinations, and 

 that of the quince only 5 per cent. ; grapes 12| per cent., being about equally 

 injured by each solution. Peaches suffered more by Nos. 10 and 12, these 

 killing some twigs; but even the least injured branch lost 40 per cent, of 

 its leaves. 



The action of these four combinations upon the fungus of the quince 

 was not marked. Some branches seemed to be benefited and others not, 

 but .none remained so healthy as those treated by Nos. 2 and 4. As 

 insecticides they were as effective as any of the preceding combinations. 



The data regarding the action of these twelve combinations upon foliage, 

 show that when Paris green is applied with the ammoniacal carbonate of 

 copper the action of the combination is more caustic than when London 

 purple is used. Also, that the addition of London purple to water holding 

 the carbonate of copper in suspension forms a more caustic combination 

 than when Paris green is added. In making out the following table of in- 

 juries sustained, only those varieties were considered which were treated 

 with both arsenites, thus making the conditions in each case the same. 

 The numbers denote the average per cent, of injury. 



