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Insect
Paranoia
Red Admiral Butterfly
and Caterpillars
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Insect Paranoia.....It’s
a common psychological disorder of gardeners and
homeowners. Minor cases are characterized by
feelings of anxieties over holes in the leaves of
plants and/or the sighting of any insects other than
butterflies in the garden or landscape. In moderate
cases, victims feel compelled to attempt
identification of garden insects, presumably to
determine whether the insect is a “beneficial
insect”, or (heaven forbid), a “pest”. Serious
cases of insect paranoia lead to the use of toxic
substances in an attempt to kill or exterminate the
offending insect, and left untreated, persons with
serious cases of insect paranoia may be dangerous to
pets, young children, and nearby neighbors.
Insect paranoia becomes more
widespread in mid-summer, because this is the time
that many insects are active in landscapes and
gardens. Holes show up in the leaves of plants,
insects of various shapes and sizes can be seen on
favorite garden plants, add to the mix a few
chemical company commercials about the potential
damage of unchecked insects, and widespread paranoia
is the result.
Good gardeners long ago discovered that as a rule,
insects simply don’t live up to the bad guy image
given to them by corporate predators trying to take
a bite out of the cabbage in a gardener’s wallet. |
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The subject of plant and insect
interactions is now being intensively studied by
biologists. There is growing evidence that beneath
the level of human observation and detection a
garden or any plant community is a very “noisy”
place. Plants signaling insects, plants signaling
other plants, insects signaling other insects—kind
of a biological version of the internet. Thus it is
no surprise when certain insects show up on stressed
plants. It’s no different than a restaurant
advertising FREE FOOD!—It’s certain to draw a
crowd.
The cure for insect paranoia is simple—Learn to do
nothing when you see insects in your landscape.
Most insect populations in a landscape or garden are
simply passing through. Serious and prolonged
insect infestations are always associated with one
or more plants that are so severely stressed that it
is unlikely that the plants will survive for long
even if you were to kill the presumably dangerous
insects.
Lady Beetle eating aphid
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Previous Articles
It's
Finally Spring - March 13
Spring Garden Calendar-March 20
No
Garden Left Behind-March 27
Planting Trees for a Cooler Earth in a Warmer
WyoBraska-April 3
Viburnums - Shrubs for Wyobraska Springs-April 10
Want A Water Conserving Lawn? You might already have
one-
April 17
Creating Long
Term
Tree-lationships April 24
Bigger, Bolder, Brighter,
Better—and Back In The Landscape May 01 & 08
Hardy Shrub
Roses
May 15
Another Look
at Native Plants
May 22
No Child
Left Inside
May 29
June
is Tree Care Month June 05
Summer Blooming Shrubs
June 12
Roses Are
Red.....
June 19
The Plants They will be Talking About Next Year at
the Garden Walk
June 26
Busy Summertime Gardens
July 03
Cutting Your Lawn Down to Size
July 10
2007 Articles
2006 Articles |
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For a variety of reasons,
these gardeners resisted the urge to spray anything
with six or more legs and they found out that the
sky didn’t fall and their gardens weren’t engulfed
by an unstoppable hoard of insects.
Insects are all an important
part of the biological processes that occur in a
garden. Bees and butterflies are important plant
pollinators. Butterfly larvae are voracious eaters,
and they can strip the leaves off of a plant in
short order. But their feeding frenzy generally
lasts less than a week before they find a quiet spot
to form a chrysalis (commonly called a cocoon) and
become a butterfly. Many insects in a garden are
actually the predators of other insects.
Wasps, lady beetles,
spiders, and praying mantises are feared predators
in the insect world.
Many other insects are
scavengers—the first step in turning your garden’s
dead leaves and stems into beautiful compost.
Spray one insect type, and you spray them all.
It
is now becoming clear that insect paranoia is mostly
a matter of a grossly incomplete and distorted view
of the way in which insects and plants interact.
Gardeners have been taught that plants are all
potentially helpless victims of random and
potentially life-threatening insect attacks.
Growing scientific evidence is revealing the
inaccuracy of that view. It turns out that plants
are continually emitting molecular signals that vary
depending upon the plant’s condition. Stressed or
injured plants emit a much different molecular
signal than they do when they are healthy. Insects
have learned to read these signals and thus know
when a plant is vulnerable to attack because its
defensive capacities are disabled.
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I have not used
any insecticide on my lawn or garden for the past 15
years. I noticed the other day an aphid infestation
on a certain group of asters. But I also noticed a
dozen or so lady beetles having a feast. A single
adult lady beetle can eat up to several hundred
aphids a day—that’s an appetite that puts a teenage
boy to shame. Several sawflies cut perfect circles
out of the leaves of my redbud every summer, but
never threaten the health of the tree any more than
a grazing buffalo threatens the health of prairie
grasses.
Monarch Caterpillar on Milkweed
And my garden attracts numerous
butterflies, so I also have lots of hungry
caterpillars every summer dining on milkweed,
chokecherry, and viburnums.
But even with holes in their
leaves, those plants remain as healthy as an
asparagus patch or rhubarb plant that is moderately
grazed by human “pests”.. If
the compulsion to do something when you see an
insect is overwhelming, think about doing something
to improve the health of the plant on which you see
an insect. Make sure the plant is receiving
adequate water. If the plant is growing slowly, a
little fertilizer may be in order. If the plant is
a tree or shrub, make sure that it is adequately
mulched. These are actions that have a chance of
actually helping the plant. And water, fertilizer,
and mulch are all safe for butterflies, birds, pets,
kids, and neighbors
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