Florida Agricultural Experiment Station


 DIRECT METHODS OF COMBATING INSECTS
 Among the direct methods of controlling insects, the primi-
tive one of collecting them by hand may be found the most satis-
factory in some cases. This is especially true in dealing with
the larger insects, which are readily seen or located by the
conspicuous damage done.
 One of the best accessories for hand-collecting is a pan con-
taining a little water covered with a film of kerosene, or the
kerosene alone may be used. The insects are knocked into this
pan, and are finally killed by the kerosene, even tho they may
crawl out of the pan.
 POISONOUS INSECTICIDES
 With reference to the use of insecticides, insects may be
divided, as stated previously, into two classes; those that have
biting mouth-parts and chew their food and those that have
sucking mouth-parts and get their nourishment by sucking the
juices of their food plants. The class of insects to be dealt
with may be determined readily by examining either the mouth-
parts of the insects or the nature of the damage to the plant.
If the insect has jaws or the plant has pieces chewed out of it,
the insect belongs to the biting class. If the mouth-parts are
in the nature of a lance or sucking tube, or the plant curls,
wilts, or turns yellow or is dwarfed, without any external in-
jury other than a small puncture, the insect belongs to the suck-
ing class. It is necessary, however, to examine the roots, as
well as the parts of the plant above ground, as injury to the
roots will cause the plants to wither and turn yellow, even in
the absence of destructive insects.
 Biting insects can be poisoned by covering the plant with
a stomach poison, some substance which, when eaten with the
plant tissue, will poison them. Sucking insects must be killed
by a contact insecticide, some substance that kills the insect by
being drawn into its spiracles. Insects do not possess lungs
and do not breath thru their mouths as do the higher animals,
but thru openings in their sides called spiracles.
 ARSENICALS.-The stomach poisons in most common use are
compounds of arsenic. The three commonly used are paris green,
lead arsenate, and zinc arsenite. The last two come in the
form of either a powder or a paste and can be applied as either
a dust or a liquid.
 Paris Green.-The oldest of the arsenicals, paris green, is
not used as extensively as formerly on truck crops, chiefly be-