Fw: Re: [GardeningOrganically] Insect control



--------- Forwarded message ----------
From: gardensmith@juno.com
To: gardensmith@juno.com
Date: Fri, 7 Jan 2000 15:49:13 -0500
Subject: Re: [GardeningOrganically] Insect control
Message-ID: <20000107.154921.-159067.0.gardensmith@juno.com>


 Fact Sheet #14Spring 1996



ATTRACTING INSECTS' NATURAL ENEMIES

When you garden ecologically, you try to keep insect pests below levels
where 
they will cause unacceptable damage, rather than try to get rid of all of
them. 
Preserving natural enemies may be the most important and readily
available 
biological control practice you can undertake in your battle of the
insects. As 
you rely on natural enemies to help you, you need to foster them by
providing 
their needs. One method consists of increasing the diversity of plants in
or 
near the garden to attract more beneficial insects to the area.

Natural enemies, or "good bugs", can provide a safe, environmentally
friendly 
means of suppressing pests. Most insects that live in or near our gardens
are 
not harmful; in fact, many are beneficial! Insects' natural enemies can
be 
predators or parasitoids. Predators such as lady beetles and lacewings
are 
mainly free living species that consume many prey during their lifetime.
Another 
important group of predators are the spiders; scientists are just
beginning to 
recognize the importance of spiders as natural enemies and in some
countries 
they are being brought in to help control insect pests. 

Parasitoids, which include many wasps and flies, are more specialized
than 
predators; the immature stage actually develops within the body of a
single 
insect, ultimately killing it. The adults are free living and often visit

flowers for nectar and pollen.

Select plants for your garden that are known to lure insects' natural
enemies to 
help you attract and conserve these garden helpers. Two large groups, or 
families of plants, are excellent "lures" - the parsley family
(Umbelliferae) 
and the sunflower or daisy family (Compositae). 

You can spot members of the Umbelliferae family by their umbrella-shaped 
clusters of small 5-petaled flowers. The overall appearance is often a
large 
flat head of white or yellow flowers; Queen Anne's lace is a good
example. The 
flower head provides a place to land for many insects, especially
beneficial 
wasps. Using a variety of these plants that bloom at different times can
make 
your garden look attractive, too. A number of culinary herbs in this
plant 
family including parsley, dill, caraway, cilantro or coriander, and
fennel. Some 
of these herbs are very attractive to syrphid and tachinid flies,
assassin bugs, 
lacewings and parasitic wasps. One caution - these plants will spread
quickly if 
left to go to seed, so remove flower heads after they stop producing
nectar, but 
before seeds mature. Also, some are biennials, so you won't see flowers
appear 
for a year. 

The Compositae family is characterized by flower heads that are actually
made up 
of many small flowers growing together. Many flowers are composed of rays
around 
a disk-like center. Many well-known ornamental flowers including
marigolds, 
dahlias, daisies, asters, cosmos, calendula, coreopsis, tansy, yarrow,
zinnia, 
and sunflowers are in this family. Flowering often lasts over a long
period of 
time and there is usually more than one flower per plant. This provides a
slow 
flow of nectar over a long period for the insects. Ladybugs, lacewings, 
parasitic wasps and some predaceous wasps are attracted to plants in this

family. Soldier beetles, flower beetles, and some lady beetles will feed
on 
pollen in addition to feeding on insects. Dandelions offer early spring
pollen 
to some of these insect predators.

Legumes such as clovers and vetch also attract beneficials. They add
nitrogen to 
the soil, provide good shelter and moisture for insects, and may even
serve as a 
source of alternative prey for natural enemies. Beneficial insects such
as 
ground beetles, rove beetles and robber fly larvae are often found in the
soil. 

Cover crops offer protection to natural enemies when our annual garden
plants 
are not actively growing. Often, beneficial insects move over from the
cover 
crops as these crops begin to die back, feeding on "bad" insects that are
in 
turn consuming the desirable garden plants. Buckwheat is a good one
because it 
not only provides shelter, but has flowers which attract flies, ladybugs
and 
pollinating bees. One caution, however, is that it does self-seed
readily! A 
small permanent planting of buckwheat near the garden allows immature
natural 
enemies to complete development without seeding up your garden.

If attracting - and keeping - the "good guys" to your garden is what you
would 
like to do, try planting a few of the "lure" plants from the parsley and 
sunflower families this year!

REFERENCES:
Natural Enemies of Vegetable Insect Pests. Michael P. Hoffmann and A. C. 
Frodsham. Cornell Cooperative Extension Publication. 48pp.
ARTICLES:
Fatal Attraction by Roger Bossley in National Gardening, May 1989. pp
34-37.

Beneficial Borders by Joanna Poncavage in Organic Gardening May/June
1991. PP 
42-45

Flower Power by Robert Kourik in Garbage, May/June 1992. pp 26-31.




Prepared by:
Carolyn Klass and Michael. P. Hoffmann, Department of Entomology, 11/95




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