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Beneficial
Insects
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Back to Insects
Heredity is a splendid phenomenon that relieves
us
of responsibility for our shortcomings. -Doug Larson
 Beneficial insects keep the balance in nature. Throughout this website
you will see mention of the many different types, what they eat, what attracts them etc.
Take a look at the the various insect entries on the natural insect
control page and on the companion planting page for specific
types and what they do for us. Most of us know what ladybugs, lacewings and praying
mantids are. Here we will touch on some of the beneficials we are less familiar with so we
can identify our allies!
Assassin
Bugs (Family Reduviidae)
- There are several species of
assassin bugs and all are beneficial. They have a black or brown body with a length of 3/8
- 2 inches. They have a thin head, bulging eyes and fly slowly. What makes them unique and
an effective assassin is their legs that have razor sharp spines. The front legs are very
strong and fast for catching and holding prey. Once they latch onto the victim they pierce
it's body with their beak injecting a venom which paralyzes the prey. The prey consists of
aphids, caterpillars, Colorado potato beetles, Japanese beetles, leafhoppers and
Mexican bean beetles. A word of caution: don't handle them as they will bite you.
- Attractant plants: Alfalfa, carrot
family plants, goldenrod and oleander.
Bigeyed
Bugs
- Like it's name states it has
extremely large eyes. The main body is grayish in color. The head and thorax have small
black spots. There are several generations per year. Adults overwinter in garden trash.
They feed on aphids, chinch bugs, leafhoppers and spider mites.
- Attractant plants:
Alfalfa, carrot family plants, goldenrod and oleander.
Ground
Beetles
- Here again there are many
different species of ground beetles. The majority being 1 inch in length. Bodies are black
to purple in coloring. They have long legs and the bodies have a hard shell. They are
nocturnal and dine on many insects including: eggs or larvae of aphids, flea beetles,
ants, nematodes, thrips, gypsy moths and mites! Along with these they also like
caterpillars, slugs and grubs. They are a gardeners pal. They are very active critters and
have been known to pursue their meal tickets up trees! Even better is they will go after
the armyworms and tent caterpillars that infest trees. The adults overwinter in the ground
and produce one offspring per year.
- Attractant plants: They like shade
and low growing plants. Any groundcovers are preferred as are camphorweed, squash and
evening primrose.
Hover
Flies:
It's a bee, it's a wasp, no it's a hoverfly!
- A hover fly is a beneficial insect
to start with. It also is a rather generic name for a large group of flies which is in the
family Syrphidae. They have similar coloring and antics compared to bees and are often
mistaken for some sort of bee or small wasp. They are 1/4-3/4 inch in length with large
eyes that take up most of their head area. Many have distinct black and yellow patterns.
We often see the adults hovering over flowers thus the name hover flies. Of interest is
they can fly sideways. They won't bite or sting you. They are most curious and like to
hang around to check us out when we are picking flowers or tending to the garden. It is
the larvae that are the predator. The adults drink nectar and is an important pollinator.
We will touch on the more common hoverflies here.
- American Hover Fly (metasyrphus
americana) : This is one of the most common and a gentle little
 critter. It has clear
wings, is 3/8 inch long, black to shiny green body with 3 yellow crossbands that don't
quite reach the stomach area. The face is yellow with a black stripe and black cheek
areas. We find this guy on flowers and foliage of all kinds. They lay long white solitary
eggs on aphid infested plants. The larvae are odd looking light gray sluggish type
creatures and they consume aphids, mealybugs, leafhoppers, thrips and scale larvae. They
can eat an aphid a minute! The larvae lifts it's victim in the air with fanglike hooks and
sucks the life juice out of it. A most beneficial helper!
- Toxomerus Hover Flies
(toxomerus spp.): Commonly known as "flower flies." They are 1/4-1/2
inch long with a black body, yellow face, belly has broken yellow bands and the thorax has
yellow side stripes. This hover fly also has clear wings but the legs are a yellowish
brown. The eggs are dusty white and laid singly on plants usually near aphid colonies.
They reach adult stage in summer. The larvae can rival in importance ladybugs in
controlling aphids.
- Attractant plants: Sweet allysum,
baby blue eyes, morning glory, cosmos, coreopsis, oleander, candytuft and white yarrow.
Watch out white yarrow is invasive. We have found that hover flies just love the flowers
of the Silver Lace Vine (Polygonum aubertii). If you have room in a sunny spot this
gorgeous vine is a rapid grower spreading to 40-60 feet wide. Once established it is
drought tolerant.
Soldier
beetles
- Adults are 1/2 inch in length and
look similar to fireflies but without the glow. They have a black body with white thorax
and head. They hibernate in the ground as larvae through the winter and have one maybe two
offspring during the season. Adults lay the eggs in clusters in the soil. These garden
soldiers wage war on grasshopper eggs, caterpillars, cucumber, flea and other small
beetles and spider mites. Of interest is the larvae like to eat bugs that dwell under a
tree's bark. Very helpful indeed!
- Attractant plants: Hydrangea,
milkweed and goldenrod.
Tachinid
Flies
- Tachinid flies look a lot like
houseflies. However it is a bigger fly being up to 1/2 long and has a grayish brown body.
The larva is yellow. Females lay their tiny white eggs on or near a host like
caterpillars, corn borers, cutworms, sawflies, grasshoppers and armyworms. One survival
mechanism is the female can literally glue it's eggs to the host. One female can lay up to
6,000 eggs. They can go hrough a complete lifecycle in 3 weeks meaning an abundance of
gareden allies all season. The larva, which is gray to white, then enter the host, feeding
off of them, parasitizing them to death. When done feeding the larvae drop to the ground,
pupate and emerge as adults in June to September. The tachinid fly is a very important
beneficial insect.
Here are recipes you can make at
home to attract the good guys to your garden. This mix is enjoyed by adult lacewings,
ladybugs, parasitic wasps and others.
- Good
Bug Chow
Mix all the
following ingredients together in a glass or plastic container:
2/3 cup of warm water
4 tablespoons of brewer's yeast
2 teaspoons of honey
1/2 cup of sugar
To use: Take 2
tablespoons of the mix and dilute it in 1 quart of lukewarm water. Use this solution to
spray on plants in the spring and early part of summer. Remember don't spray plants when
temperatures are over 80F. Store the mixture in a sealed container in the refrigerator so
it won't go rancid. It will keep for 7-10 days. The sugar in it is actually good for your
plants.
- Sugar-Water Spray
Mix together very thoroughly these ingredients:
32 ounces of warm water
5 ounces of white sugar
Apply as needed to your plants when aphids and other soft bodied are a
nuisance.
Research done at Utah State University indicates that spraying this
sugar-water solution in the center of an alfalfa field increased the
ladybug population in one to two days by 200% to 1300%.
Copyright © Golden Harvest
Organics 1997-2008
Update:
04/17/08
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