Florida Agricultural Experiment Station


 DUSTS.-The use of dusts in place of liquid sprays is be-
coming common. They are especially adapted to cheap farm
crops but are used on the truck farm to check an insect out-
break in its early stages. They are best if applied in the early
morning when the plants are wet with dew.
 In a small garden the dust may be applied by shaking
from a perforated tin can or from a bag made of muslin, but
on a truck farm a dusting machine should be used. There are
many of these machines on the market, ranging from a small
bellows-like affair to a large power duster driven by a gasoline
engine. Those which can be carried and operated by a man
while walking thru the field will be found quite satisfactory for
truck farms. The prices of these range from ten to fifteen
dollars. Undiluted arsenicals can be used in the machines, but
it is usually more economical to dilute them with at least equal
parts of some carrier such as hydrated lime, air-slacked lime,
land-plaster, or flour.
 CONTACT INSECTICIDES
 TOBACCO.-This is one of the most common of the contact
insecticides used against small and delicate insects. It is also
one of the safest for in excessive dosages only is there any
danger of scorching the plants. For directions for its prepara-
tion and use see melon aphis under watermelons, page 199.
 KEROSENE EMULSION.-For large insects, as well as small
ones, kerosene emulsion is a standard remedy, but unless made
and applied carefully it is likely to scorch tender foliage. The
stock solution is:
 H ard soap .......................... ............................ 1/ pound
 Hot water (soft) ..... ................---- .....1. gallon
 Kerosene (coal oil) ..................................... 2 gallons
 Shave the half pound of laundry soap into the gallon of
 soft water, stirring it until the soap is dissolved. When all is
 in solution, remove the liquid to a safe distance from the fire
 and add the kerosene. Emulsify the solution quickly with a
 bucket pump by turning the nozzle back into the bucket and
 forcing the solution thru the pump several times until a smooth
 creamy emulsion is formed. If this is done properly no free
 oil will collect on the surface when the solution cools.
 For spraying dormant trees and shrubs use 1 part of the
 solution to from 5 to 7 parts of water. On ordinary growing
 plants dilute with 10 to 15 parts of water, depending on the
 insect to be killed. The weakest solution given will kill plant
 lice.