20 CIRCULAR 4 6 4, U. S. DEPARTMENT OE AGRICULTURE 



For applying burlap bands knives should be supplied for cutting the 

 burlap and the twine and destroying the caterpillars. For applying 

 sticky bands, knives or steel brashes should be used to destroy the 

 caterpillars, and tree scrapers will be required to smooth the rough 

 bark before the bands are applied. 



The most expensive item in gypsy moth work is the spraying ma- 

 chinery and the equipment necessary to operate it. If orchard trees 

 or low growth is to be treated, an orchard sprayer equipped with one or 

 more lines of hose and with nozzles of the vermorel or bordeaux type 

 will be satisfactory. The object of treatment is, of course, to cover all 

 the foliage evenly with a thin deposit of spray. The higher the trees 

 the more difficult it is to apply the material without waste. T\ Then 

 large shade, park, or woodland trees are to be treated, high-powered 

 spraying apparatus and use of the solid-stream type of treatment will 

 enable the work to be done rapidly. For best results the machine 

 should be equipped with hose 1 inch in diameter, and a nozzle pressure 

 of 300 pounds per square inch should be maintained. The speed of 

 the pump must be regulated according to the aperture of the nozzle. 

 Since the quantity of liquid passing through increases with the diame- 

 ter of the tip, the pump pressure has to be stepped up to furnish the 

 300-pound nozzle pressure necessary to break up the spray. As hose 

 lines are lengthened or the elevation of the nozzle above the spraying 

 machine increases, there is a loss of pressure at the nozzle due to the 

 friction in the hose and the additional height to which the spray 

 material must be forced. The pump should be of the triplex type, 

 capable of delivering at least 35 gallons of liquid per minute for a short 

 spray line. A spray tank of 300 gallons' capacity is commonly used, 

 and the tank and suction line should be provided with strainers to 

 keep out foreign matter, which will either injure the pump or clog the 

 nozzle. 



One-inch hose capable of withstanding a working pressure of 600 

 pounds is satisfactory for most park and shade-tree work, where ex- 

 tremely long lines of hose are not required, or where isolated areas 

 are to he treated and the equipment has to be moved frequently. On 

 larger and more extensive areas, or where a water supply is some 

 distance away, a higher-powered machine and hose that will withstand 

 a working pressure of 1,000 pounds per square inch are necessary 

 (fig. 9). To perform a maximum amount of work the sprayer should 

 be set at the water supply. If the machine is equipped with an 

 auxiliary pump for drafting water to supply the tank, and the tank 

 is divided, one section can be filled while the other is being emptied 

 as the spraying operation proceeds, and continuous spraying will 

 result. With equipment of this type and on areas where there are 

 slight elevations, 4,000 to 5,000 feet of hose can be laid to reach 

 outlying areas. 



In the intensive work that is being carried on by the Bureau of 

 Entomology and Plant Quarantine in some of the outlying areas 

 longer hose lines are necessary, and on account of higher elevations 

 the sprayer and the hose are required to pass a performance test of 

 1,500 pounds' working pressure. As much as 12,000 feet of hose has 

 been used on work of this type. Sprayers are constructed either with 

 a power take-off or as individual imits, so that they can be transferred 

 to a truck and moved to points where they are needed in the field. 

 With this type of machinery and the proper diameter of tip on the 



