Evening star., 1945-06-03

SOIIle years IlldIl OItlcIS. lie ii
each one individually if he is to be
successful in their control
While the entomologist carefully
describes each of the many pests
and has endeavored to give us q
personal introduction, such aid Ii
hardly necessary. The garden pests
for all practical purposes can be put
into three groups: l, Chewing in
sects; 2, sucking insects, and 3, scale
insects. The latter are of little i'm.
portance to the vegetable grower
since they are troublesome only or
ornamentals and fruit trees.
Group one, the chewing insects
are controlled through the use Of
stomach poisons. The most desir-
able of the stomach poisons, rote.
none, is not too plentiful in supply
but what is available is for use or
vegetable crops. 1t should be usec
either as dust or a spray for the
control of all chewing insects, which
includes the cabbage worm, the
Mexican bean beetle, etc. Rotenone
is nonpoisonous to warm -bloodeo
animals. Furthermore, it does not
burn bean foliage which makes il
ideally suited for the control of the
bean beetle. The one drawback tt
the use of rotenone is that thu
scarcity of supply requires that it b.
spread as far as possible and so the
available dusts contain but u pei
cent, whereas the preferred strength
is q per cent. However, the cur.
rently available dusts are effective
when carefully and regularly used,
A second stomach poison, cryolitt
Frequently sold under trade names
is also effective and recommended
for use on those crops whose edible
portions are not touched by The
spray material. Cryolite does no
injure bean foliage, hence may b.
used on them until the pods begir
to form. 1t is especially useful il
fighting the flea beetle on tomatoes
eggplant and potatoes.
The third stomach poison, Leaf
arsenate, is an old standby, but on,
that is not now recommended TO
use on'vegetables. 1t is highly pois
onous and will burn tender foliag,
such as garden beans. On the othe
hand, it is cheap and available.
The control of the second clas
of garden pests, the sucking insect.
is through contact" spray or dust
Sprays are usually more effectiv
than dusts but a dust will work
Nicotine sulphate is the most com
monty used and effective contac
spray for the sucking insects, sucl
as the thrips and aphids. Plant lice
as they are also called, insert thei
beaks into the plant tissues an
suck the juices, hence a stomacl
poison is of no value in their con
troll. The nicotine sulphate. usual
sold under trade name, is highl
effective as spray and mixed wit
an absorbent is used in dusts. Con
tact sprays or dusts to be effectiv
must come into contact with tn
sucking insects so the sprays of dust
should be put on them rather thai
on the foliage.
In addition to the nicotine sui
phate gardeners oftentimes use
strong soap solution and find
effective. A hard blast from tn
garden hose will usually knocl
aphids to the ground.
The third group of insects, th
scale insects, are controlled durin,
the winter season with a so-calle,
dormant spray. 1t is applied t,
dormant deciduous plants while tn
temperatures are above freezing. I
is strong enough to kill the insect
under the scales, hence will burr
foliage. Most gardeners use dor
mant strength lime-sulphur spray
to kill the scale insects.
In addition to the insects gar
deners usually have to fight plan
diseases. In general there are tw
basic materials for their control
% Copper compounds of whicI
Bordeaux Is the most commonl