15 



APPARATUS FOR SPRAYING. 



For applying the liquid to the trees, a force-pump, to which is attached 

 a few feet of hose, fitted at the end with a spraying nozzle, will be needed. 

 Excellent pumps are now made by the larger manufacturers expressly 

 for spraying purposes, fitted with all necessary attachments, and cost- 

 ing $10 and upwards. Smaller pumps, which would answer fairly well 

 for a few trees, may be had at from $2 to $10 each. 



The same pump which is used for treating tiie trees for the apple 

 scab may of course be used for applying poisons for the codling moth 

 and other insects. Unfortunately it will not be prudent to add the 

 copper carbonate solution to the same water that is used in applying 

 Paris green or London purple, as the ammonia renders the arsenic 

 more or less soluble and thus the latter would be liable to injure the 

 foliage. But if applied a few hours in advance of the water containing 

 the arsenites, no harm can result from this source. 



SUGGESTIONS FOR FURTHER EXPERIMENTS. 



The time at which the applications should commence, the number 

 that should be made, and the amount of copper carbonate to be used 

 to accomplish the greatest benefit at the least cost, remain to be 

 settled by experiment. 



The most practical remedy for the apple scab must be one that may 

 be applied in the same water with Paris green or London purple with- 

 out thereby endangering the foliage. It is the opinion of our station 

 chemist, Dr. Babcock, that not only the ammoniacal copper carbonate, 

 but the sodium hyposulphite and the sulphides of lime and potash, 

 all tend to render the arsenic of Paris green and London purple soluble, 

 and hence can not be wisely used in connection with these poisons. 

 The copper carbonate, however, which in the ammoniacal solution is 

 the beneficial agent in preventing the apple scab, does not have this 

 effect when used without the ammonia. The question therefore arises, 

 is the ammonia solvent necessary ? 



I have recently made some tests with a sample of commercial precipi- 

 tated copper carbonate, and find that its state of division is such 

 that it remains suspended in water rather better than Paris green, and 

 so may be applied by any apparatus that successfully distributes the 

 latter. It apparently adheres to the foliage nearly or quite as well, 

 when applied in simple suspension, as in the diluted ammoniacal solu- 

 tion. 



I recommend, therefore, that those who spray their apple trees for 

 the prevention of injury from the codling moth, make the experiment 

 in a portion of the orchard of adding the. precipitated copper carbon- 

 ate to the water, at the rate of an ounce to twenty-five gallons. ISo 

 harm to the foliage can result from this measure, while we have every 

 reason to expect that much benefit will accrue in the prevention of the 

 apple scab. 



University op Wisconsin, Madison, Wis. 



