74 MARYLAND AGRICULTURAL EXPERIMENT STATION. 



Inirn the foliage, but this difficulty is easily overcome by the addition of 

 a small quantity of lime water to the mixture, thus transforming the sol- 

 uble arsenic into insoluble calcic arsenite. 



The use of ordinary white arsenic is not advised because of its in- 

 solubility and its color, Mhicli renders it indistinguishable from some 

 harmless substances for which it is apt to be mistaken, so that it is more 

 dangerous to have about .the farm in quantities. 



Either London purple or Paris green, then, should be thoroughly 

 mixed with water in the proportion of one pound of the poison to 150 

 gallons of water, and this mixture should be thrown in a fine spray 

 through the trees, so as to thoroughly moisten all parts of the leaves and 

 fruit. I cannot too strongly urge the advantage of careful spraying 

 which shall cause a uniform fall in the form of a mist, and not drench the 

 tree, and thus cause the concentration of the poison in particular spots. 

 The spray should be forced from the center of the tree and then all 

 around it, in an even mist, which will settle uniformly on all j^arts. 

 The lirst application should be made about a Aveek after the blossoms 

 fall and before any of the larva* have hatched or entered the fruit, as the 

 efficacy of the spraying depends upon the larv;v taking a small quantity 

 of the poison with their first meal in eating through the calyx of the 

 young apple. Unless a heavy fall of rain should follow this first appli- 

 cation, the spraying will not have to be repeated. A small quantity of 

 flour or starch mixed in at the time of stirring the poison in the Avater 

 will tend to make the spray adhere better and more uniformly, but these 

 sticky substances should not be mixed with London purple as they ])ve- 

 cipitate the poisoh and rather increase the ine(iuality of its distribution.. 



One great advantage of such spraying is that in addition to greatly 

 lessening, if not practically checking, the work of the Codling Moth, it 

 also destroys a great numlier of insects which feed upon the leaves of the 

 apple tree, and in a measure will also serve as a protection against certain 

 fungus diseases. AVhere orchards are seriously affected with rust or scab, 

 it is desirable even to combine with the arsenical spray a certain amount 

 of Bordeaux mixture, and a good formula for this last is, 7 pounds of 

 unslaked lime, (5 pounds of copper sulphate (or blue stone), 2 pound of 

 London purjde, and 75 gallons of water. 



Apparatus for Spraying. — For orchard use, the knapsack pum^DS or 

 bucket pumjjs are i)ractically unavailable, however useful for a few trees 

 by means of ladders. I shall therefore not consider them in this connec- 

 tion, but refer to a few of the more important tank or barrel })umps and 

 state the requisites of a good orchard spraying apparatus. 



The following firms manufacture spray pumps of several styles" and 

 are always glad to send circulars to fruit growers: 



Nixon Nozzle cS: Machine Co., Daytom Ohio. 



Field Force Pump C!o., Lockport,'N. Y. 



Deming Manufacturing Co., Salem, Ohio. 



W. & B. Douglass, MiddletoAvn, Conn. 



The Gould's Company, Seneca Falls, X. Y. 



