SPRAYING FOR THE CITRUS MEALY BUG 253 



solution is allowed to stand for some time it is best to stir it up before diluting 

 it for spraying. 



The resulting spray is very easily handled, it needs no agitation, no 

 straining, is easily and simply made, does not rot the hose or rust iron pipes, 

 and is perfectly harmless to the eyes and hands of the sprayers. 



Applications : In spraying for insects which are protected by a wooly, coi 

 tony, or waxy covering, it is essential that an adequate force behind the 

 spray be employed. In the case of the mealy bug it is absolutely necessary to 

 have a power spray pump. This will enable the sprayer to develop the powei 

 necessary. In our work the least pressure used was 100 pounds and the 

 most satisfactory pressure 250 pounds. A three nozzled spray seemed to give 

 the best results, for a thorough drenching could be given any spot instantly, 

 and the top of the tree could be more effectively reached. With such a spray 

 there is little danger of missing any considerably surface of the tree, a thing 

 to be guarded against, for every spot untouched means not a few mealy 

 bugs left alive on the tree for the next year. This can be avoided only by 

 thorough work and regular applications. If a few insects are left in a se- 

 cluded place it will not be long before the young are born and the adults die, 

 or the adults themselves, may move to a more favorable place. The young 

 always move away from the parent and often rove extensively after hatching. 

 The life cycle is quite long, lasting from six to nine months, so three applica- 

 tions of spray within this time will surely eliminate most of them. In a badly 

 infested orchard an application should be made once every two months until the 

 conditions are made much better. 



In the experimental and field work where the trees were normal in size, 

 and badly infested with eggs, larvae, and adult mealy bugs, 15 gallons were 

 given to each tree, at an application. 



Cost of Spraying: In large quantities the cost of materials is as follows : 



Crude Carbolic Acid 25c per gal. 



Whale Oil Soap 63/ic per lb. 



A mixture of 43 gallons of stock solution according to the above formula 

 would cost $3.85. This stock solution makes 860 gallons of spraying material 

 less than j/^c per gallon. Using 15 gallons per tree this would make the 

 cost near 7c a tree for a single application. After the first two sprayings 

 it would not be necessary to give such a large dose, which would cut down 

 the expenses somewhat. The labor would probably cost less than the cost 

 of chemicals per tree. 



Comparing spraying with fumigation, every argument of expense is 

 with the former, and the results are certainly greater in proportion to the 

 cost, for each application and as many applications are necessary for fumi- 

 gation as are for spraying at a cost of about five times as much every time. 



Time for- Spraying : In a badly infested orchard the work should be 

 taken up just as soon as possible so as to eliminate all of the insects exposed. 

 After two or three successive sprayings within six or seven weeks, a regular 

 system should be followed, just as we fumigate regularly for black scale. 



