SPRAYING WORK OF THIS SEASON 



BY J. J. LEVISON, M.F. 

 FORESTER TO THE CITY OF NEW YORK 



T 1 1 IS is the time when all nature awakens. The insects 

 awaken also, and we have to meet their destructive 

 invasion. Just what to spray and what material to 

 use is a matter that varies with the plant and the insect, 

 and before one can determine what is needed, an effort 

 should be made to receive specific advice based on the 



INJECTING CARBON BISULPHIDE FOR BORING INSECTS 



The liquid is injected by means of a metallic syringe and the orifice clogged 

 with soap to hold the fumes generated by the liquid within the burrow. 



particular insect and the tree in question. Without consid- 

 ering individual questions, we can, however, to advantage 

 discuss in a general way the important methods of spraying 

 and how to combat some of our most serious enemies. 



We spray for insects that either chew or swallow the 

 leaves of trees or those that merely suck the sap from 

 leaves or bark. A poison applied' to the surface of the 

 leaves will cause the chewing insects to swallow it with 

 the leaves and become internally poisoned. Arsenate of 

 lead serves that purpose and is most commonly used at 

 least more so than Paris-green, which is another poison 

 occasionally substituted. 



To combat the sucking insects, no such application of 

 arsenate of lead to the surface of the leaves would ever 

 reach the insects, because the latter penetrate through 

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the outer tissue of the leaf and suck the sap from the in- 

 terior. To be effective against sucking insects, the chem- 

 ical required must be of such a nature as to injure the 

 insect by contact with its tender body. The various oil 

 emulsions in the market, such as kerosene emulsion, lime 

 sulphur wash, scalicide, miscible oil, fish-oil soap, and the 

 nicotine and tobacco concoctions are all based on this prin- 

 ciple. Which one of these to use and at what strength is a 

 matter that varies with the season, the insect and the plant. 

 In dormant seasons one can use a stronger solution 

 than in' the summer time because then there is no likeli- 



HAND-POWER SPRAYING APPARATUS 



This is a very convenient way of applying the spray to trees. More powerful 

 gasoline sprayers are required where very tall trees are to be sprayed. 



hood of burning the leaves or the open buds. In the dor- 

 mant state one may also have to meet an insect heavily 

 protected with an outer scale or possibly in the egg stage, 

 and consequently requiring a stronger solution. The partic- 

 ular species of tree would also make some difference because 

 some trees are more tender to oil emulsions than others. 



With these preliminary remarks to put us on the right 

 track, let us make up a simple spraying calendar which 

 will hold good for the majority of cases of spraying during 



