a. Kerosene and Diesel Oil. Kerosene and diesel oil, both available from
military stocks, can be used as mosquito larvicides. They are also used as carriers for
some of the more toxic insecticides, which must be diluted for use.
b. Pyrethrum. One of the most effective and widely used natural organic
insecticides is pyrethrum, which is derived from one variety of chrysanthemum flower.
Pyrethrum is a powerful contact insecticide causing a rapid paralysis or
"knockdown" of the treated insect.
It is effective as a direct contact or space spray against adult flies,
mosquitoes, and other flying insects.
It lacks persistence and has virtually no residual action.
Many insects, especially cockroaches, recover after an initial contact.
Pyrethrum is one of the least toxic of all insecticides to mammals, and its
use poses no environmental hazard.
c. Synthetic "Pyrethroids.' Because of the high cost of pyrethrum, several
synthetic "pyrethroids" have been developed which mimic the activity of pyrethrum and
are now being substituted for pyrethrum in the standard pressurized aerosol can.
6-16. SYNTHETIC ORGANIC INSECTICIDES
The synthetic, or man-made, insecticides first came into use with the synthesis of DDT
in 1939. During and following World War II, their use and development mushroomed.
There are currently three categories of synthetic organic insecticides in the Army
inventory: chlorinated hydrocarbons, organic phosphates, and carbamates.
a. Chlorinated Hydrocarbons. These chemicals are characterized by their
prolonged residual effect. Some have shown effective persistence for over 10 years in
tests where massive soil treatment was used, as in termite control. Because of this
persistence, the registrations for several of the chlorinated hydrocarbons have been
suspended or cancelled (DDT for example).
There are currently no chlorinated hydrocarbons on the Army stock list.
b. Organic Phosphates. The organic phosphates are characterized by faster
action and more rapid decomposition than the chlorinated hydrocarbons. For this
reason, they are not considered as detrimental to the environment as are the
chlorinated hydrocarbons. To human applicators, however, they may pose greater
health and safety hazards than the chlorinated hydrocarbons.