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Control. Experience has shown that after a community has endured
hordes of beetles for several years their numbers decline, partly due to
natural parasites. Tiphia wasps, introduced from Japan, have been released from Connecticut to Virginia. Grubs have been given milky disease,
in the form of bacterial spore dust applied to turf, 1 teaspoon at 3-foot
intervals. Some succumb to blue disease, probably of virus origin, and
others to a green fungus.
DDT, applied to the turf at the rate of 6 pounds of a 10% dust for each
1000 square feet, controls grubs for at least 3 years. Chlordane, 5 pounds
of a 5% dust for the same area, has a quicker reaction but perhaps a
shorter residual effect. Some proprietary formulations combine DDT and
chlordane. Aldrin is also effective. Treatments may be made in May or
early autumn. The dust can be mixed with several times the amount
of sand, broadcast evenly or applied with a fertilizer spreader, then
washed in well with the hose. If power apparatus is available, the chemicals can be sprayed on the lawn, keeping children and pets away until
it has dried.
Spraying with DDT, methoxychlor, or lead arsenate often enough to
protect new growth will keep foliage of roses and other plants from
being chewed up by beetles, but there is little to do about blooms except
to cut your best buds as they show color and enjoy them in the house
during July and August. Roses are best in June before the beetles appear
and in the fall when most of them are gone; so there is no reason at all
to stop growing roses just because you live in a Japanese beetle area. For
grapes, raspberries, and other fruits use a rotenone spray with a sticker
sold especially for Japanese beetles. Methoxychlor, which is less poisonous
to man than DDT, can be used on some fruits. Bright yellow traps catch
beetles, but they attract far more than they trap, so they are not advised
for small gardens.
LADY BEETLES.
The name goes back to the Middle Ages, when these
garden friends were dedicated to the Virgin, becoming "beetles of
our Lady." Lady beetles are broadly oval, with head nearly concealed by
the thorax. Those that are red with black spots often prey on aphids. The
small two-spotted lady beetles are common not only in gardens but in
houses in winter. They don't do any harm, and they do help clean up
lice on the ivy tips, so don't kill them. There is one keeping me company
as I type this, sometimes on the windowsill, sometimes perched on the
typewriter. The sluglike larvae, black, marked with blue and orange, eat
aphids as avidly as the adults.
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Types of Garden Enemies
