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BY
The University
of Nebraska-Lincoln published in 2009 two new Extension Circulars with
beautiful color pictures of beneficial insects. When I printed them off
from the computer my wife and I were surprised at how many of these we
had been killing because we thought they were hurting our plants. To get
your copy of these two Extension Circulars go to your local
In a previous
article I mentioned that many gardeners are going after Aphids with the
insecticide “Sevin” only to discover a couple weeks later, they are
worse than ever. “Sevin” is a good insecticide and widely used but it is
also very deadly to many beneficial insects such as bees, other
pollinators, and the “Lady Bugs” that eat Aphids. Many garden centers
have gone to “Eight” which is not as harsh on beneficial insects and can
even be used on many houseplants. If Aphids are a problem for you, start
out using “Insecticidal Soap” rather than a harsh chemical that kills
everything. Many gardeners in the past have used a dishwashing liquid
but it is not a good substitute. Dishwashing liquid has a rinsing agent
so the soap will rinse off our dishes and glasses but this not good on
plants as you don’t want your insecticide to easily wash off your plant.
Many Insecticidal Soaps are made from oils that come from the “Neem
Tree” that has insecticidal qualities which is an added benefit.
I get very
upset with the commercials I hear on TV and radio and see in the
newspapers and magazines that brag about their lawn insecticide and how
many insects they will kill above and below the ground. I wonder why a
homeowner wants to kill all their insects? The sign of a health lawn
includes having many worms in the soil. And most of these formulations
do not kill grubs that can be very detrimental. I also get upset when
everyone advertises their 4, 5, or 6 step lawn programs that
automatically include a general insecticide to kill all the insects in
your lawn. The only insecticide I put on my lawn is a “preventative”
grub control containing imadicloprid (Merit). In most parts of
What are some
of the most common beneficial insects? The first one that comes to mind
is the “Ladybug”. Ladybugs are not only effective but are economically
important. They feed on many different soft-body insects with aphids
being their main food source. During larval periods the Ladybug
resembles a tiny, black, six legged alligator with orange spots. As
larva it will gorge on about 400 aphids. After 3 or 4 weeks it attaches
to a leaf or twig and enters the pupal stage. In another week the pupal
skin splits and a hungry young adult emerges to resume feeding on other
insects. As an adult it may
eat another 5000 aphids. Up to 1,500 tiny yellow eggs may be deposited
in clusters of 10 to 50 in just a few weeks. In good years several
generations may be produced. The Ladybug’s huge appetite and
reproductive capacity allows it to rapidly clean out its prey.
Probably the
next well known beneficial insect is the “Praying Mantis”. The Praying
Mantis, because of its appearance and attitudes, is a fascinating
insect. It is strictly carnivorous and feeds on almost any insect of a
size it can overcome. Praying Mantis egg cases are harvested in their
natural environment. The female deposits the eggs in the fall in a
frothy secretion that hardens and protects the eggs from predators and
severe winter climates. Egg
cases attach to twigs, leaves, fences, etc. and many contain 50 to 400
eggs with an average of about 200.
Upon hatching in the spring the young crawl from between tiny
flaps in the case and hang from silken threads about two inches below
the case. After drying out, the long-legged young disperse into the
vegetation leaving little, if any evidence of their appearance.
This happens within an hour or two and it is very difficult to
know hatching has occurred unless the elusive, well-camouflaged young
are found.
Not so well
known are the Green Lacewing and the Brown Lacewing. “The Green Lacewing
is a green, soft-bodied insect with four, clear membranous wings with
green veins, long hair-like antennae, and golden eyes. They are about
three-fourths of an inch long. The larva are small “alligator-like”
insect with a flattened body that tapers at the tail, large mandibles,
greenish gray or brownish body color and about one-eight to three-fourth
of an inch long. The eggs are oval, laid singly at the end of a long
silken silk, pale green when first laid and later turning gray.”
“The Brown
Lacewing adult is a soft-bodied insect with four, clear membranous wings
with green veins, long hair-like antennae, and golden eyes bout
three-fourths inches long.”
“For both the
Green and Brown Lacewing the adults may be generalist predators or
pollen and honeydew feeders, depending on the species. The larvae are
generalist predators feeding on aphids, thrips, spider mites, small
caterpillars, leafhoppers, mealybugs, psyllids, whiteflies, and insect
eggs.” (From “Beneficial Insects I by Copyright 2013 |