Evening star., 1937-07-17
RED SPIDER PERIL
TO TREES IS TOLD
Oil Sprays Usually Found
Effective in Destroying
Insects Eggs.

The red spiders which infeSt shade
trees constitute an insect-like pest
ranable of doing much harm. and
inform alton about them should Be
helpful to the home owner in pro-
tecting his trees from their ravages,
according to Paul Davey. well-known
tree expert He continues:
"The red spider, or spider mite, is
co. Of the tiniest creatures which live
IL trr~ x.-- sther forms Of plant
lite. Full grown. they are from less
than one-sixteenth OF an inch long
down to sixty-fourth OF an inch,
and they do not have to be full grown
10 do damage to plant life. There
are many different species, most OF
which will thrive on any sort Of plant
host. although some are more limited
In their tastes, as indicated by such
common names as spruce mite, dog
wood mite, etc. They may be red,
green. brown, orange or almost black,
although 10 many of them are of some
ahade OF red or brown that they are
commonly called red spiders or red
mites.
Because they are so tiny it is not
always easy TO distinguish their pres
erce on trees unless the infestat ton
IL quite serious. One way to find out
whether there are any red spiders
there is to hold a piece of white paper
under branch and rap it sharply.
F1ecks of dust and bark will drop on
the paper and If any of the flecks OF
dust start walking around, you will
know they are spider mites. Put
magnifylng glass on one and YOU will
discover an exceedingly active little
eieht-legged spider.
Similar to Aphids.
Red spiders are similar to aphids In
their feeding habits They suck the
Juices from the leaves. But, unlike
the aphid. the spider mite seems to
Get some Of the chlorophyll, or green
coloring matter of the leaf, with the
result that for each time a spider
mite pierces leaf there will be
little graySh spot where the color
Ing matter has been removed. This
spot will later turn brown. and a leaf
which has had number of the mites
will present a mottled appearance
The spider mite spends the entire
year on one host tree. Eggs over
Winter in the crevices of the twies
and hatch with the first warm
weather. More eggs will be laid dur
Ing the Summer and number of
generations will be produced in one
season. AS each female may lay as
many as 100 eggs the rate OF in
crease is likely to be astoundingly
rapid.
Problem Of Control.
"1naSmuch as both eggs and living
mites are present at the same time,
the problem OF control is not so SIM
pie as in the case OF sucking insects
which produce living young. con-
tact spray is needed to kill the living
mites. but the nicotine mixtures us
lally effective as contact sprays will
not destroy the eggs. The most ef-
fective control measures for Summer
Use consist OF repeated spraying with
Summer oil mixtures, the Summer
oil being obtainable in good supply
houses under several trade names.
For dormant spraying the oils usually
used will destroy the eggs.
Another method which has been
found effective on small trees is TO
Wash them down with a forceful
stream m Of cold water This kills many
Of the mites and those not actually
killed do not thrive in dampneSs
But whatever method Is used, it Is
veil to remember that the mites null
tlply rapidly and that it is impossible
10 get 100 per cent effectiveness with
one treatment. Repeated applca-
tions are necessary all through the
season to eradicate them"