House plant damagers . . . here are actions to take
Tiny creatures will gladly make your house plants their home unless
you stop them. To stop them with an effective control, take a good
close look at your plants; one of these five intruders could be the
cause of your plant troubles:
Aphids are recognized by soft, round, pinhead-size bodies that may
be whitish, green, or black; they often huddle together on new shoots,
buds, and leaves.
Mealybugs look like tufts of cotton with fringed edges
(there’s one in the photograph above); they feed on plant juices
and are often found along stems.
Mites (actually spider relatives, not insects look like specks of
reddish dust on plant leaves; they stipple leaves with little yellowish
spots by sucking plant juices. If you suspect that a plant has mites,
shake the leaves over white paper and look for dust-like specks that
Scale insects appear as small lumps (usually tan) on stems and
leaves. A waxy stationary shell protects the insect as it feeds on
plant juices, exuding a sticky substance that darkens leaves.
Thrips show up under a hand lens as fastmoving tannish specks.
Their small size (1/25 inch) makes them hard to see. Damage to leaves
shows in a dull, silvery upper surface; numerous black dots of excrement
on lower leaf surfaces will confirm their presence. When numerous
enough, they distort foliage by rasping into unopened flowers and
leaves, leaving strips of seersucker puckerings.
Spraying infested plants will kill plant damagers, but can cause
logistical problems when you try to spray in a practical and safe place.
Systemic insecticides, added directly to the soil, provide an
alternative to sprays.
Use only sprays labeled for house plant application. There are
many on the market in both aerosol and pump-type dispensers. The
insect-controlling ingredients are usually nicotine, pyrethrins, and
rotenone (alone or in combination). One pump spray contains an
insect-growth regulator that provides long-lasting control. Check the
label to make sure the spray is both safe for your plant and will kill
the creature you’er aiming for.
When you spray plants, do the job outdoors, out of direct sunlight
and away from wood or upholstered furniture. If you have a plant too
big to move, you can fashion a fumigation tent from a plastic laundry
bag; spray and keep the bag sealed for two weeks. Water plants well
several hours before you spray them to lessen the danger of the
chemicals burning the leaves. Wash your hands after you finish the job
and keep children and pets away from the sprayed plants.
Systemic house plant insecticides are easier and safer to apply
than sprays, and they usually remain effective longer (up to six weeks).
Systemics are taken up by the plant’s roots and travel through the
conductive system to all branch and leafparts. They poison the
plant’s juices, killing creatures that feed on the plant.
To lessen the chances of an invasion, keep plants clean–free of
dust–by wiping or showering them off every couple of weeks. Inspect
stems and leaves routinely and often for tiny creatures. Check new
plants carefully before you introduce them to your collection.
Photo: Fuzzy white lump at the base leaf is a mealybug, shown here
four times actual size. Oval body is covered with waxy threads