Evening star., 1949-05-15
Batting the Garden Insects
Latest Materials Described-When to
Use and What Results Can Be Assured
By w. N. Younamoa
oardsn kdises

none Ia an ideal tnsecttcids for
the vegetable garden but ross-
none does not kill al insects and
thus has its limitations. Aowsver.
1t does control tbs Mexican bean
beetle. which DDT does not. and
most of the other common insects
Of the vegetable garden. Rots-
none should make up y per cent
Of the mixture.
Pyrethrum kills some insects
that rotenone does not, hence
we usually find It combined
with rotenone In the combination
dusts. II is also effective against
some Of the sphids.
Nicotine suIphats dust q .
tobacco dust may be included as
q specific for the control Of aphids.
those tiny, green. sap-sucking In
sects that must be hit BY the
material to be killed. Nicotine
sulphate Is thus called Q contact
insecticide.
Lead arsenate, tho old standby
for controlling leaf-eating In
sects, is a deadly poison and
should not be used on fruits or
vegetables unless they are to be
carefully washed before using.
Also, the fallen spray remains In
the ground and will accumulate.
For this reason it is not con-
sidered a desirable material and
its use is rapidly being super
seded by the newer DDT.'
ChIOrdane has not as yet been
widely introduced into the COM
bination sprays and dusts since
it's limitations are not fully de-
termined. 1t looks promising but
until better known should be used
only experimentally.
Psrathion, similarly. u too new
TO have been fully explored. Both
are potentially important to home
gardeners but their usefulness is
still to be determined.
Formerly, Bordeaux mixture
was the standard material used
to control plant diseases. Un-
fortunately, the material 80 coat
ed the leaves as to reduce their
normal functioning. Sulphur was
tried in a variety of forms and
for several uses replaced Bordeaux
mixture. However, sulphur burned
the foliage during periods Of high
temperature and thus often could
not be used with safety when
needed. Fermate. a new formu-
lation Of sulphur. seems to be free
OF this Objectionable feature.
Many of the combinations contain
fermate as well as . limited
amount of sulphur. Combination
sprays or dusts containing sui
phur may not be used on cucum-
bers. squash and melons.
A group Of materials carrying
metallic copper have proved their
usefulness In controlling certain
plant diseases. In addition. there
Is q group of chemicals. common
ly referred to as "carbamates"
and sold under trade names.
which appear to be even more
effective than either Bordeaux or
sulphur In the control Of plant
diseases. They are being used In
some of the all-purpose dusts
and sprays. but In most cases
they are listed by their trade
names, such as zerlate. parasite.
etc. |
Dahlia and boxwood fans will
ask what about the red spider
mite? They have been using DDT
to control the leaf miner. Eu-
ropean stalk borers and other
pests only to discover that the
DDT killed the natural enemies
of the red spider mite. HETP
(Hex-ethyl-tetra- -phosphate) was
brought forward to do the job,
but If the combination contains
sulphur or nicotine sulphate
HETP will not be needed.
The choice between q dust or
a spray probably will depend upon
the size of the job-good Job II Q
thin coating of dust is placed on
both sides Of the foliage. A spray
may be applied under less favor
able conditions, will last longer III
1t contains . good spreader and
sticker), but 1t takes more equip
ment and time. This implies that
the average gardener viii do .
better Job and get better results
with q dust. which may or may
not be true.
The effectiveness Of any control
Of insects and diseases depends
upon having the material on the
plant before the bug takes . bite
or q disease spore arrives. Thus
Of applications II Of
major Importance. AZ . rule IN
should be made after
each shower. and at not Q greater
interval than weekly since the