EPM
(Ecological Pest
Management)
What is Ecological Pest
Management?
Ecological Pest
Management (EPM) is also called biointensive IPM. EPM originated from Integrated Pest
Management (IPM) and shares many of the
same components as conventional IPM, including monitoring, use of economic
thresholds, record keeping, and planning.
An important difference between conventional and biointensive IPM,
however, is that the emphasis of the latter is on proactive measures to redesign
the agricultural ecosystem to the disadvantage of a pest and to the
advantage of its parasite and predator complex (ATTRA).
Pest management is an ecological
matter. The size of a pest population and the damage it inflicts is, to a great
extent, a reflection of the design and management of a particular agricultural
ecosystem. The design and management of
our agricultural systems need re-examining. We’ve come to accept routine use of
biological poisons in our food systems as normal. Attempting to implement an ecology-based
discipline like IPM in large monocultures, which substitute chemical inputs for
ecological design, can be an exercise in futility and inefficiency (ATTRA).
According to ATTRA, IPM, as it was
originally conceived, proposed to manage pests though an understanding of their
interactions with other organisms and the environment. However, IPM has strayed from its ecological
roots. Critics
of what might be termed “conventional” IPM note that it has been implemented as
Integrated Pesticide Management (or even Improved Pesticide Marketing) with an
emphasis on using pesticides as a tool of first resort. What has been missing
from this approach, which is essentially reactive, is an understanding of the
ecological basis of pest infestations. Also missing from the conventional
approach are guidelines for ecology-based manipulations of the farm
agroecosystem that address the questions:
Ø Why is the pest
there?
Ø How did it
arrive?
Ø Why doesn’t the
parasite/predator complex control the pest?
Guidelines for ecology-based manipulations of the farm agroecosystem:
For more information on biointensive integrated pest
management strategies visit the National Sustainable Agriculture Information
website and click on:
Dr. Mcbug’s website (see information below) is a
very good resource for EPM.
A first step in ecological pest
management is learn more about pests and beneficial insects that may be present
in your fields. The Alabama IPM
Communicator contains some valuable information about which pests are present
in AL crops and this week Dr. Ayanava
Majumdar, Extension Entomologist, begins a series about insect predators: Know
Your Friends: Alabama IPM Communicator,
June 15, 2012. Volume 3, No. 8:
Every week I will post
organic-relevant information from the Alabama IPM Communicator.
Below is the excerpt from this
week’s newsletter:
KNOW YOUR FRIENDS:
INSECT PREDATORS—LACEWINGS
& LADY BEETLES
By
Dr. Ayanava Majumdar
Beneficial insects are an important
part of the natural ecosystem and provide a valuable service to crop producers.
An acre of crops can have a significantly large number of insect predators and
parasites (in fact, according to published scientific literature from Arkansas
and California, there can be more species of beneficial insects present in a
cropping system than pest species). However, low populations and cryptic
behaviors of predators make them appear as if they are ineffective. Through
this newsletter section called “Know Your Friends”, I will attempt to
familiarize readers with one or two beneficial insect species in every issue
and explain their field usage technique as recommended by the industry. Organic
as well as conventional farmers should use selective insecticides in a timely
manner to minimize impact on the beneficial insect populations.
Sources of beneficial insects:
Numerous vendors sell
beneficial insects via their website along with plenty of good information. For
example, Arbico Organics (AZ), Orcon (CA), Grow Organic (CA), Gardens Alive
(IN), and Nature’s Control (OR) sell insect predators in large numbers and at least
one vendor sells it as a ‘beneficial insect program’ with weekly shipments
adjusted to your pest control needs. Note that beneficial insects are
slow-acting in pest outbreak situation, so use beneficial insects preventively
when pests are in low populations and have not overwhelmed the crops you are
trying to protect. Follow the release instructions that come with the products
and modify your spray schedule to adjust for the presence of beneficial
insects.
[Note: The Beneficial Insect Company in NC is
another source for beneficial insects.
GREEN LACEWINGS
Many species of lacewings occur
naturally in cropping systems. Green and brown lacewings are most common
predators of aphids, so they are also known as the ‘aphid-lions’. Green
lacewings are larger in size than brown lacewings. Lacewing adults lay eggs
singly or in small groups attached to various plant parts. Green lacewing eggs
have a stalk to protect the developing larvae from other predators. Brown
lacewing eggs do not have a stalk. Lacewing eggs hatch in 3-6 days. Lacewing
larvae look like small alligators and have large-sickle shaped mandibles that
are used to catch prey. Larvae pierce the body of prey and suck juices. Green
and brown lacewing larvae may look similar in appearance with 2 to 4 white
spots on the top of body; however, the brown lacewing larvae have a
side-to-side ‘head-wagging behavior’ that is not present in green lacewings.
Besides aphids, these larvae can feed on whiteflies, caterpillars (fruitworms,
loopers, armyworms), and even eggs. Each larva takes about 2 weeks to develop
and may feed on 250-300 aphids per week. Green lacewing larvae pupate inside a
cocoon attached to plant parts and adults emerge in about 2 weeks. Brown
lacewing pupa is elliptical with a loose cocoon through which the pupa is
visible. Lacewing adults are good fliers that are strongly attracted to light
and can fly many miles immediately after emergence. Adult lacewings have
delicate body and transparent wings with many veins visible (‘net-like wings’).
Adults feed on pollen and nectar. Female lacewings can lay 200-800eggs and live
for many weeks. The green and brown lacewings overwinter as adults but there
are other species that can live as pupae during winter. About 2-3 generations
may occur every year.
|
Larva with large sickle-shaped mandibles |
|
Eggs on stalks glued to a leaf |
|
Pupation inside a cocoon occurs on plants |
|
Adult lacewing with large wings |
Image
sources: Oregon SU, University of Arkansas, Wikipedia, Iowa SU
Lacewing eggs
can be purchased in large numbers from many suppliers. This approach to insect
control is called ‘inundative biological control’ as pest management is
expected from the released individuals. Alternatively, lacewing eggs may be
released in an ‘inoculative approach’ where long-term establishment of the
beneficial insect is desired. Due to rapid flight of adult lacewings out of
their release site and lack of food, the inoculative approach may not always
work on many farms. Therefore, some vegetable producers with high tunnels and
greenhouses routinely use lacewings in conjunction with parasitoids for
broad-based pest management. Identify the pest first and then purchase the appropriate
predator. [See Dr. McBug’s website for more information about
how to keep these beneficial insects around].
Commercial
lacewing eggs are packed in bran and the container can be kept refrigerated
(not frozen) for several days. Do not transfer contents into another container
for storage. Purchase eggs early in the week so they arrive in mail ready for
release. A good practice is to check the viability of these eggs by retaining
some eggs in a vial at room temperature and let them hatch in captivity. Eggs
need to be scattered on plant surfaces while avoiding the presence of other
predators like ants (please follow the instructions that come with your
purchase). Manufacturers like Arbico Organics recommend 1000 eggs per 2500
square feet. Up to 50,000 eggs may be needed per acre for large scale release.
CONVERGENT
LADY BEETLE
This is a very
common species of lady beetle among the numerous others present in any crop
field. The conver-gent beetle is common in Alabama and also very popular
beneficial insect sold by companies, hence is worth discussing here.
The insect
name comes from the two white lines seen on the thorax of adult beetles (arrow
in picture) that seem to be coming together on the top. The number of dots can
vary from none up to 13, so counting the dots alone is not a good identifier
for this beetle. Larvae are black with rows of orange spots. Not that the lady
beetle larva have chewing mouthparts and do not have the sickle shaped
mandibles of the green lacewing larva (previous page). Eggs are elliptical and
bright yellow in color; eggs are laid in clusters on plants with over 10 eggs
per cluster. Eggs can also be laid in soil or plant debris. Pupae are immobile
(nonfeeding stage) and may be seen stuck to plant parts.
|
Eggs on plant surface |
|
Larva |
|
Pupa |
|
Adult lady beetle |
Image
sources: Univ. of California—Davis, Iowa SU
Adults and
larvae feed on aphids. Adult beetles also feed on nectar and pollen. According
to industry sources, each adult lady beetle can destroy about 5000 aphids while
the larvae can consume nearly 400 aphids in a week. In the absence of aphids,
convergent beetles can also feed on moth eggs and small caterpillars. Female
convergent beetles lay up to 1000 eggs in ideal conditions and have a lifespan
of 1 to 3 months. Larvae feed for 3 weeks and adults emerge 2 to 5 days after
pupation. Adults do not fly if air temperatures are below 55F. There can be
many generations of this insect every year.
The presence
of a large number of lady beetles can indicate the presence of aphids. This
insect can be the most abundant predator in cotton fields. Many suppliers sell
lady beetles in the adult stage when they are ready for field release. The
adult beetles can also be stored in their original package for some duration.
Industry sources recommend the release rate of 4500 beetles for 2500 square
feet and much larger numbers for large areas. Out migration of adults once prey
numbers dwindle is a major cause of loss of these powerful natural control
agents. Routine release of beetles in large numbers can be effective in
enclosed structures for aphid control.
I will
continue to update this discussion of natural predators from the next issues of
the IPM newsletter. Remember that parasitoids and pathogens also act in
conjunction with predators to provide natural control of pests. Do your own
research before purchasing large batches of predators and carefully plan the
release for the best effect. Follow the instructions that come with your
purchase of beneficial insects. Providing cover crops or shelter plants during
fall season is a good way to facilitate continuity of predators in an area.
In addition to
the AL IPM Communicator, below are some very good resources on designing a farm
system that attracts and maintains beneficial insect populations.
Additional Resources on Ecological Pest Management
In addition to the AL IPM Communicator, below are
some very good resources on designing a farm system that attracts and
maintains beneficial insect populations.
How to Get Started with IPM—Planning, Planning, Planning (excerpts from
Biointensive Integrated Pest Management)
:
Good planning must precede implementation of any
IPM program, but is particularly important in a biointensive program.
Planning should be done before planting because many pest strategies
require steps or inputs, such as beneficial organism habitat
management, that must be considered well in advance. Attempting to
jump-start an IPM program in the beginning or middle of a cropping
season generally does not work.
IPM options may be considered proactive or
reactive. Proactive options, such as crop rotations and creation of
habitat for beneficial organisms, permanently lower the carrying
capacity of the farm for the pest. The carrying capacity is determined
by factors like food, shelter, natural enemies complex, and weather,
which affect the reproduction and survival of a species. Cultural
controls are generally considered to be proactive strategies.
The second set of options is more reactive. This
simply means that the grower responds to a situation, such as an
economically damaging population of pests, with some type of short-term
suppressive action. Reactive methods generally include inundative
releases of biological controls, mechanical and physical controls, and
chemical controls.
Proactive Strategies (Cultural Controls)
- Healthy, biologically active soils (increasing belowground diversity)
- Habitat for beneficial organisms (increasing aboveground diversity)
- Appropriate plant cultivars
Maintaining and increasing biological diversity of
the farm system is a primary strategy of cultural control. Decreased
biodiversity tends to result in agroecosystems that are unstable and
prone to recurrent pest outbreaks and many other problems. Systems
high in biodiversity tend to be more "dynamically stable"—that is, the
variety of organisms provide more checks and balances on each other,
which helps prevent one species (i.e., pest species) from overwhelming
the system.
Creation of habitat to enhance the chances for
survival and reproduction of beneficial organisms is a concept included
in the definition of natural biocontrol.
Farmscaping
is a term coined to describe such efforts on farms. Habitat enhancement
for beneficial insects, for example, focuses on the establishment of
flowering annual or perennial plants that provide pollen and nectar
needed during certain parts of the insect life cycle. Other habitat
features provided by farmscaping include water, alternative prey,
perching sites, overwintering sites, and wind protection. Beneficial
insects and other beneficial organisms should be viewed as
mini-livestock, with specific habitat and food needs to be included in
farm planning.
Examples of how to use farmscaping effectively in
your farming system can be found in the references below. Green
lacewings and convergent ladybeetles are generalist predators that feed
on a variety of pest insects so they are good beneficial insects to
keep around your crops. Appendix A in
Farmscaping to Enhance Biological Control lists plants that attract beneficials.
To attract and conserve
green lacewings,
plant members of the carrot family (caraway, Queen Anne's lace, tansy,
dill, angelica), sunflower family (coreopsis, cosmos, sunflowers,
dandelion, goldenrod), buckwheat, corn, and provide water during dry
spells.
Convergent lady beetles: Once
aphids leave a crop, lady beetles will also. To retain active lady
beetles , maintain cover crops or other hosts of aphids or alternate
prey. Plant members of the carrot family (fennel, angelica, dill,
tansy, Queen Anne's lace), sunflower family (goldenrod, coreopsis,
cosmos, dandelion, sunflower, yarrow), crimson clover, hairy vetch,
grains and native grasses, butterfly weed (
Asclepias), black locust, buckwheat, euonymus, rye).
Note from Appendix A that these same plants attract
a large variety of beneficial insects. Also note that these
farmscaping plants are already present in most diverse organic
agroecosystems as herbs, cut flowers, or cover crops. By allowing some
of these crops to flower they can serve double purposes in your
cropping system.
Beneficial organisms should be viewed as mini-livestock,
with specific habitat and food
needs to be included in farm planning (ATTRA).
Grow Your Own Bugs: Managing
For Beneficial Insects or Plant It and They Will Come!
For information on how you can attract and maintain
populations of beneficial insects in your gardens and fields visit the website
of Dr. Richard McDonald (aka Dr. McBug):
www.drmcbug.com.
Click on the links at the top of the page for pictures and
information on pests, beneficials, and farmscaping plants (plants for the
purpose of attracting beneficial insects), epm (ecological pest management),
and other valuable sources of information.
Farmscaping for Insect Management: Integrated
Parasite/Predator/Pathogen Management & Strategies for Encouraging
Beneficial Insects in the Field or "if you plant it, they will
come...." Richard McDonald, Ph.D., Symbiont Biological Pest Management,
194 Shull's Hollar, Sugar Grove NC 28679;(828) 297-BUUG (2884); e-mail: the_edge@goboone.net website: www.drmcbug.com.
Farmscaping - Dr. Robert BUGG - Definition:
Deliberate use of specific plants and landscaping techniques to attract and
conserve "Beneficials". Feed your bugs -
Dr. McDonald's Applied Farmscaping Principles:
1) Farmscaping is part of a Multiple Redundant Systems (MRS) approach
- MRS is a form of disaster preparedness - triple redundancy is desirable for
plants and insects. So for both you want "guilds" of
food plants and natural enemies to protect your plants. This is why we
list more than 10 beneficial food plants per season - more
than one natural enemy attacking each life stage is better, too. Less can lead
to breakdowns.
2) Anticipate Pest
Problems - Think Ahead - encourage the right beneficial insects to be there when you need
them to attack the pests. Ladybugs/trichogramma wasps attack the eggs of
caterpillars.
3) Specific Plants
attract specific beneficials - example: fennel is great for attracting parasitic wasps, syrphid
flies, and ladybugs. So one plant can bring in a guild of beneficials.
4) 5-10% of crop area
should be planted in farmscaping plants- "lots of clumps of food plants spread out over an area is
much better than one big clump"!
5) Consider Dispersion
indices for insects when foraging - "Insect Specs":
Low
Dispersion- (Stay in field)
|
Medium
Dispersion (forage 1/4 mile)
|
High
Dispersion (forage > 1/4 mile)
|
Ground
Beetles (Carabids)
Ladybeetles
(when happy)
|
Most
Parasitic wasps
Predatory
Wasps - Paper
|
Syrphids
- Hover Flies
Dragonflies,
Tachinid Flies
|
Smaller
Parasitic Wasps
|
Predatory
Bugs
|
Larger
Parasitic Wasps
|
6) Have something
blooming all the time - Flowers are
prime food & mating sites for wasps. Important to have a well fed, mated
female beneficial! Green House - use to Jump-start garden areas.
7) Nectar - liquid sugar food + vitamins for
beneficials. Nectar is critical for optimum performance of many beneficials.
Many beneficials will lay over 3-fold more eggs if properly fed. Example:
Parasitic wasps egg laying capacity - poorly fed - 30 eggs; if she is well fed,
over 300 high quality eggs. Some of the best plants you can have for this
purpose are those in the wild carrot family (also known as Umbellifera), such
as dill, fennel, tansy, queen Anne's lace, caraway, coriander, parsnip, etc.
8) Extra-Floral
Nectaries - nectar glands that are
not associated with flowers. Peonies, Sweet potatoes, bachelor buttons, all
have extrafloral nectaries. Parasitic wasps and flies use these extrafloral
nectaries as important food sources.
9) Pollen - Is an alternative form of protein. Once
again, many plants in the wild carrot family can provide pollen. Another good
pollen producer is the corn plant. Syrphid flies need pollen to lay eggs.
10) Overwintering sites
for beneficials - It turns out
that many beneficials make cocoons and hibernate in or very near the plants
where they find their hosts. Recent research has shown that yarrow and comfrey
are also excellent overwintering plants for parasitic wasps.
11) Entrainment - (entomologists- Joe Lewis really opened up
this field) have discovered that insects (especially parasitic wasps and flies)
can perform associative learning, so if you get insects (especially young ones)
happy in their environment, they will "tune in" to a particular pest.
A good way to do this for a predator or parasite is to release it on or nearby
the intended prey.
12) Drought/Stress - These systems can also fail! In drought years
insects from all over will come to your area and can overwhelm a system. Be
ready with backups additional insects,ladybugs/lacewings, Bt, soaps,
diatomaceous earth. Save the soap/de for last, because they kill anything.
Finally,
13) Your Design
Decisions Mantra: Encourage Biodiversity! - Remember that insects are part of the web of life in your
garden or farm. The beneficial insect complex is not only composed of parasitic
wasps and flies, predatory beetles, lacewing larvae, ladybugs and so on, but
ALSO the pollinators, antagonists/competitors that occupy and compete for space
and food with potential pests, and finally the saprophytes and decomposing
insects that help complete the food cycle back to the soil so the cycle can
start again. And remember, "If you plant it, they will come...." For
further information on Farmscaping, go to my web site (www.drmcbug.com) and
click on the farmscaping section. Also see ATTRA's Farmscaping publication at their website (www.attra.org).
The gist of this message is that, just like us, beneficial insects need sources
of food and shelter in order to stick around. You can weave "web of
life" in your garden/farm by planting specific plants that attract
specific beneficials. Also, by thinking ahead and anticipating the types of
pest problems you might have, you can encourage the right beneficial insects to
be there when you need them to attack the pests. My motto is: "If you
plant it, they will come. Or, I will buy them (beneficials) once and have them
here forever after..."
FARMSCAPING - Top Plants
for Beneficials
Spring: brassicas - ground ivy, wild mustards, Tulip poplar,
vetches, pussy willow, yarrow, umbels - parsley/parsnip/ coriander, buckwheat,
clovers, mints, Norway Maple, grains, peonies, borage.
Summer: mints, wild carrots- cow parsnip, tansy, bronze fennel,
smartweed-Vietnamese Cilantro, Jerusalem artichoke, kenafe, sweet potato,
borage, smartweed, bachelor buttons.
Fall: Patrina, Autumn joy sedum, vetches, chrysanthemum (Pacifica),
tansy, bronze fennel, Queen Anne's Lace/other wild carrot family plants, garlic
chives, Goldenrod, yarrow, comfrey and some of the last broccoli for
overwintering on/underneath.
Top Beneficials
1. Ladybugs 2. Predatory Bugs -
Big-Eyed/Nabid(Damsel)/Assassin/Stink/Pirate(Orius) Bugs. 3.Syrphid Flies 4.
Parasitic wasps 5. Lacewings 6. Parasitic flies 7. Ground beetles 8. Spiders 9.
Mantids 10. Dragonflies
Common Pests that we can
control:
1. Whiteflies 2. Flea beetles 3. Spider Mites 4.Cucumber beetles 5. Aphids 6.
Japanese beetle/Exotic scarabs 7. Squash Vine Borers 8. Cabbage Caterpillars 9.
Mexican Bean Beetle 10. Stink bugs
Other resources for
Ecological Pest Management:
USDA Alternative Farming Systems Information Center:
Biointensive Integrated Pest Management: National Sustainable Agriculture Information
Center: