- 5- 
The amouBt of protection obtained from the application of 
ineecticidal spray is also dependent upon ths precision with which 
it is directed at the dahlia plants. Axial and terminal bud growth 
should he wet thoroughly without washing away residues already de- 
posited in them. These residues are caused by the use of the ben- 
tonite clay. Best results are obtained when sufficient pressure is 
used to force the insecticide deeply into bud growth. It is essen- 
tial to stir the spray thoroughly when it is mixed and to agitate 
it frequently during application. Choice blooms intended for exhi- 
bition should not be wet by the spray after petals show color in 
the flower buds. The use of overhead irrigation after sprays or 
dusts have been applied reduces the effectiveness of ineecticidal 
residues because they are readily diluted and washed from the plants. 
Tor growers who prefer to apply insecticides in dry powder or 
dust form, several preparations containing nicotine bentonite are 
available in packages. These are sold under various commercial 
names and are mixed and ready for use as purchased. To be effec- 
tive, they should contain not less than 4 percent of nicotine. 
Equipment for Applying Insecticides 
Standard sprayers having capacities of from 2& to 30 gallons 
have been found satisfactory for use in dahlia gardens. Excel] ent 
results may be obtained with 2$- or 3-gallon, hand-operated, portable 
sprayers, as illustrated in figure k, if the pressure is maintained 
by frequent pumping. The small quart-size atomizers operated by a 
plunger of the bicycle-pump type are not always dependable for ob- 
taining satisfactory control* In gardens of 500 or more plants 
greater convenience is afforded by a wheelbarrow type of sprayer 
equipped with a 12- to 2fr-gallon supply tank and 15 feet of hose. 
The working radius of a wheelbarrow sprayer is increased when the 
first few feet of ho«eline have been elevated sufficiently to permit 
extension of the hose in any direction. This can be accomplished 
readily by attaching to the wheelbarrow frame a 3"* or *+-foot length 
of iron rod or strap which has been bent into a loop at its top for 
holding the hose above the sprayer. 
To facilitate direction of the spray to various plant parts, 
the sprayer hose should be fitted with a lever-operated valve for 
controlling the spray discharge, and an 18- to 2 1 +-inch brass exten- 
sion pipe, as shown in figure k. The outer end of the extension 
pipe should be equipped with a suitable nozzle for breaking the 
stream of insecticide into a fine misty spray. 
lay of the various types of hand-operated dusters is capable of 
depositing a sufficient quantity of insecticide on the dahlia plant. 
The hand-operated knapsack type of duster is most suitable for use 
in both small and large plantings of dahlias. The round terminal 
opening on the 18- to 2U-inoh extension tube of most dusters 
provides a satisfactory discharge of dust; no special nozsle is 
necessary* 
