Insects of Shade Trees and Their Control. 95 
with small spraying outfits as with larger ones. These nozzles are 
usually provided with three interchangeable disks or plates, each 
having a different sized opening to give a fine, medium, or coarse 
spray. The spray material passes through a tangential opening into 
the eddy chamber, where it obtains its whirling motion and escapes 
through the opening in the disk. The disk nozzles are relatively 
small and compact and, owing to the absence of any appendages, do 
not catch in the branches of trees as happens with other designs. The 
coarse spray disks deliver a fairly large quantity of spray material, 
and can not be used satisfactorily 
with pumps of small pressure ca- 
pacity. With the smaller spraying 
outfits the disks having small aper- 
tures should be used. 
NOZZLE Y. 
For rapid spraying, with outfits 
having sufficient capacity and _pres- 
sure, two nozzles per rod may be used. 
These can be attached to the spray rod 
by means of a Y. 
& 
i 
E 
5 
E 
& 
SPRAY RODS. 
Spray or extension rods (fig. 13) 
are employed in order to reach the 
upper and inner parts of the trees. 
These generally consist of an alumi- 
Fig. 12.—Large eddy-chamber or 
num, brass, or iron rod contained RG ol dials Gyperot meade: ata 
within a bamboo pole and are usually seta or crook. (Quaintance and 
© Siegler.) 
made in lengths of from 6 to 14 feet. 
Some fruit growers use an ordinary gas pipe, but the lighter weight 
spray rods are much more desirable. 
ANGLE SHUT-OFF. 
An angle shut-off, connecting the spray hose with the base of the 
spray rod, is a convenient device for cutting off the spray material 
whenever desired, as in passing from one tree to another. The angle 
construction permits the hose to hang in its natural position, and 
thereby saves the hose from wearing at the coupling. Without an 
angle shut-off, spray material is frequently wasted because of the 
inconyenience of closing the stopcock. 
