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Beneficial Landscaping - Insects

Beneficial Landscaping: Native Pollinators – Our Help in Ages Past, and Present

Colony Collapse Disorder (CCD) has caused widespread declines in the beekeeper-managed European honey bee colonies. These colonies are used extensively to pollinate agricultural crops. This year, the scarcity of hives caused California almond growers to pay $150 for each bee hive they rented for pollination services. The specter of CCD, the cause of which remains a mystery, is disturbing. We rely upon animals to pollinate over 70% of the world’s crop species, which yield about 30% of our food and drink in the U.S. Can we survive without this valuable ecological service? Will we have to do this work ourselves?

Researchers are finding that native pollinators, specifically native bees, are also important pollinators. There are about 4,000 species of native bees in North America. Among them, for example, are tiny carpenter bees, sweat bees, longhorn bees, and bumble bees. Native bees are responsible for approximately $3 billion in produce annually in the U.S. In fact, these unsung heroes cause honeybees to be more effective, they are more efficient than honeybees, 100% pollination occurs only when native bees are present, resulting in greater crop production, and there are no rental fees! Given a chance, native bees could help to fill the pollination gap.

So how do we help them to help us? Mace Vaughan, Conservation Director and Entomologist/Educator at the Xerces Society for Invertebrate Conservation, offers answers. He says we can offer them nesting sites, a variety of flowering plants that can provide a continuous supply of nectar and pollen, and refuge from pesticides. Whether you manage a farm, a garden, or other managed landscape, Mr. Vaughan’s guidance will help you to establish a healthy population of native bees on your land:

Preserve natural areas. Natural areas can be provided in small patches or in marginal areas across, within, and/or adjacent to your farm or garden. Farm ponds, fence rows, or field margins are examples.

Ensure adequate nest sites. Examine your property for existing bee nests and protect them. Ground nesting bees often occur in well-drained, bare, sandy loam soils that are not tilled every year. Tunnel nesting bees use holes in old snags or the center of pithy twigs. Artificial nests can be made by boring holes in lumber or creating small patches of bare soil with sparse vegetation.

Provide forage areas. This can be done by leaving weedy borders, allowing cover crops to bloom, growing a diversity of crops or other flowering plants, and/or planting patches of native flowers. The idea is to always have something in bloom from spring to fall. Forage patches should include flowers that bloom before and after the crop for which pollination is most needed, in order to sustain the adult bees through 5 weeks of activity and successful reproduction.

Provide refuge from pesticides. Avoid using pesticides. If pesticides of any kind must be used, apply them just after dark. Never apply insecticides to blooming plants, including weeds at the field margins. Use pesticides that are least toxic to bees, and practice integrated pest management.

Of course, the cultural practices that foster native bees provide a host of other benefits, such as protecting water quality, preventing soil erosion, supporting other beneficial insects, maintaining biological diversity of local plants and animals, and visual aesthetics, to name just a few. Why not give it a try?!

For more information about this and other topics in beneficial landscaping, contact Elaine Somers at 206-553-2966, 800-424-4372 x 2966, or Or, visit our website at

This article was adapted from publications and presentations by Mace Vaughan, Conservation Director of the Xerces Society for Invertebrate Conservation, . We extend our sincere gratitude to him, and to the Xerces Society, the NRCS, and other collaborators, for their valuable research and educational efforts.


Beneficial Insects – Wanted Alive

Hold your insecticides! We’ve asked Sharon Collman, entomologist and WSU Snohomish County Extension agent, to write a series of WaterTalk articles about beneficial insects in our gardens. Here’s the first installment…
Good Bugs at Work
Sharon J. Collman,
WSU Snohomish County Extension

Bugs are good for the garden. Perhaps your awareness of insects came from a painful incident with yellowjackets as a kid, or from the focus on pests as garden writers provide helpful advice. Horror movies capitalize on our fears of the unknown and instill images that foster more fear. Certainly, there have been pests that have plagued humans and those that require control. Fleas, mosquitoes, lice can be vectors of disease at their worst and just plain annoying at their best. Then there are carpenter ants, food pests, and caterpillars that may require our intervention.

But take heart! Only a few insects are actually harmful, as we define it; 90-95% of the insects are working for us in our gardens by pollinating our crops and preying upon the harmful insects. Yes, harmful insects do get out of control when the number of beneficial insects drops. When the beneficials are too successful, the pests become scarce so the beneficials can’t find them. As the pest population builds back they are easier to find, so the beneficials are more successful. But during this shift in populations, there is usually a lag time. Humans get impatient and often apply pesticides just when the beneficials have found the pests. Knowing when to intervene and when to let things alone takes a bit of careful attention, and it helps to know who’s who out there. So let’s take a look at the who’s who of beneficial insects that keep pests pretty much under control.

Ladybugs are pretty well known, but not always their larvae or eggs. They are only one of the enemies of aphids and other sucking insects. All that honeydew, the excess sugars excreted by the aphids, has a nice odor on a sunny day and tells all the downwind predators that there are aphids aplenty here. You’ve seen orange and red and black ladybugs, but watch for tiny black or medium pink ones, and the eggs or larvae.

Take a favorite beverage, sit comfortably in the garden by your roses and watch beneficial insects (pollinators, predators, and parasitoids) working for you to keep pest numbers low.

For more information about Beneficial Landscaping, contact Elaine Somers at 206-553-2966,, or visit the website at


Crane Flies, Healthy Lawns, and Water Quality

To water quality folks, crane fly larvae are indicators of good to fair water quality and stream health because they are somewhat sensitive to degraded water quality.

However, the homeowner is most familiar with the newly introduced pest, the European crane fly, which caused significant lawn damage when it was first introduced into the U.S. Homeowners with a lawn problem will quickly blame crane flies and, often without thinking, will apply pesticides to bring about control. The one pest European crane fly should not be confused with the many beneficial native crane flies that are valuable as part of the food chain, indicators of water quality, or that work as decomposers of organic matter on land.

The European crane fly was introduced into the U.S. in 1969 and quickly gained public notice when the larvae stripped many lawns and pastures bare. It is not uncommon for newly arrived pests to be very damaging in the early years, because they arrive without their normal predators and parasitoids (parasites that kill their host, instead of living in the host without killing it).

Because the European crane fly was new, and because homeowners put high value on their lawns, crane flies received lots of extra media attention. However, thirty years later, the natural enemies such as soil microorganisms, and birds have found crane flies and are important in reducing their numbers. Now we only have normal ups and downs in crane flies numbers. Even so, homeowners have not fogotten, and continue spray for crane flies, even when none are there.

We also know more about the pest crane flies. Research experience has shown that healthy turf on good soil can withstand high populations of crane fly larvae. At the Washington State University and Oregon State University Research and Extension Centers, turf scientists (Drs. Gwen Stahnke and Tom Cook respectively) have found populations as high as 60 to 80 larvae per square foot in their plots with NO significant damage. (Note that turf researchers are very fussy about turf quality). They recommend that, in most cases, homeowners should spend their efforts on improving lawn health. In most cases, proper fertilization will help the lawn outgrow any damage. If homeowners check their lawns during late winter and early spring, they will have plenty of time to intervene if the crane fly starts to get out of hand.

Todd Murray, IPM Coordinator with the WSU/Whatcom County IPM Project, trained volunteers to monitor lawns around Lake Whatcom. They rarely found enough larvae to warrant treatment. (See website listed below). But, a far more serious problem has developed due to careless application of pesticides for controlling crane fly, and other pests. With the high media profile, the public has come to know, and to blame, crane fly for ANY lawn problem. Consequently, excessive and unnecessary pesticides are being applied and they are showing up in urban streams. The common pesticides used on crane flies have been diazinon (which has caused several bird kills) and dursban,and both have been found in urban streams.

To improve communication about crane flies, researchers, educators, and regulators in the Pacific Northwest (US Environmental Protection Agency, Washington State University and Oregon State University researchers and Cooperative Extension agents, Washington and Oregon Departments of Agriculture, and other area specialists) are collaborating to share information via a new website. The website covers basic information on crane fly identification and management, current research reports, technical references, photos and information on how to join a discussion list on pest crane flies. This information is available at

Where lawn damage is observed check carefully. It is possible the lawn is suffering from previous lack of water, heat or drought intolerant grasses, poor drainage (evident if you squish your way across the lawn) or from lawn diseases - many of which also can be controlled by good lawn care. The turf speciealists state firmly that good lawn care is the best control of crane flies. To review good turf care, see the WSU Home Lawns Bulletin at It is easy to read and understand.

We are the "big brains" of the natural world. We can do better. With a little thought, we can have good lawn quality without environmental damage if we will "Target the pest, and protect the rest".


Dragonflies, Living Flashes of Light
by Ralph Thomas Rogers, EPA’s resident dragonfly expert

One of the many fruits of beneficial landscaping is the provision of habitat for native creatures and the opportunity for watching them. Ralph Rogers provides a 2-part series on dragon- and damselflies. This issue's Part 1 is a fascinating look into their world; Part 2 is about dragonfly habitat and how to create it.

For more information about Beneficial Landscaping, contact Elaine Somers at 206-553-2966 or, or visit the website at

Summer is the premier season to observe the multitude of flying insects which inhabit marshes and other wet places. For size, flying ability and beauty few, if any, insects can rival the dragonfly or its cousin, the dainty damselfly. For thousands of years humans have marveled at dragonflies. They have been depicted in ancient and modern oriental art in paintings, tapestries and woodcuttings. The Nootka Indians of the Pacific Northwest conferred the name clacking stick on dragonflies and included them in their totems and on personal decorative objects. Tennyson referred to them as “Living Flashes of Light.”

Insect Cousins
Dragonflies were contemporaries of the first reptiles more than 300 million years ago and were around long before the mammals and flowering plants. Dragonflies and damselflies (referred to as Odonates of the insect Order Odonata) share characteristics which, in combination, distinguish them from other insects: two equal or nearly equal pairs of wings; large compound eyes; short, threadlike antennae; a long, slender body; and young that are aquatic and develop from eggs to adult through a nymphal stage.

Damselflies are delicate and weak fliers. When at rest, they hold their wings folded or slightly spread over their abdomen, butterfly fashion. Damselfly compound eyes are widely separated on either side of the head. Dragonflies, on the other hand, are strong fliers with robust bodies, and when perched, they hold their slightly unequal pairs of wings straight out to the sides like oars. There are 88 species of Odonates in Oregon and 80 species in Washington, and 97 species for both states combined. About 450 species occur in North America.

Courting - A Tandem Affair
One of the most observed dragonfly behaviors relates to courtship and mating, a behavior which is unique among insects, culminates in male and female tandem flights so commonly seen in summer and early fall. This flight is initiated by the male when he pursues a female that has entered his territory. The male clasps the tip of his abdomen to the back of her head, and they fly in a tandem coupling, male in front, while the female curls her abdomen to form the mating “wheel” prior to egg laying. Damselflies mate in the same manner except that the male clamps on to the female’s thorax rather than behind the head.

Nymph to Adult, Voracious Predators of Two Worlds
Dragonfly young, which rival any scifi aquatic creature in appearance and method of procuring food, spend their youth underwater catching other insects, tadpoles and even small fish with their hinged, lightning-fast, extendible mouthparts. The amount of time spent preparing for an aerial adulthood may be as long as five years in some cold water species to as short as a few weeks in warm water species that live in small, vernal pools which dry up by summer’s end. Dragonfly young can be grouped as Climbers, Sprawlers and Burrowers. The former are active foragers with streamlined bodies and keen eyesight for stalking prey. They derive their name from their active crawling over submerged vegetation. The prawlers and burrowers are more sedate, preferring to either lie on top of the bottom ooze and debris or, in the case of burrowers, actually within the silt and muck, awaiting unsuspecting prey, which they snare with their hooked, prehensile mouthparts.

After the voracious young dragonfly has stored enough energy to make the transformation to adult, it crawls from the water on a stem of vegetation where its skin is shed. This generally occurs under the cover of darkness or in early morning, since this is a vulnerable time in its life. The result is a winged hunter, as ravenous a predator as its younger self, but this time exploiting a new habitat. It is interesting to note that a
mosquito missed in its aquatic larval form may now be snatched by the same dragonfly in a different arena. The adult will also feed on a variety of insects, which they capture and eat while in flight by forming a “basket” with their six barbed legs. Sometimes the larger species will also feed on smaller dragonflies and damselflies and are themselves food for many species of birds. In their juvenile stage they are eaten by fish, aquatic birds, amphibians and other invertebrates.

Dragonfly Watching
Dragonflies become sexually mature within a few weeks after emergence and begin the life cycle all over with males establishing territories near water which they patrol in search of mates and to ward off males of the same species. Conflicts between different species at the same habitat are reduced by variations in patrolling and perching habits. Although fights and some mortalities do occur, the aerial battles within and among species help reduce the competition and number of encounters. Females are seldom seen near the water at this time unless they are ready to mate or lay eggs.

Larger lakes usually have poor Odonate populations except in sheltered areas where wave action is reduced and marshy habitats have become established. The best places to watch dragonflies are in marshy small ponds, warm water streams and similar places.

Next issue, learn about naturescaping to attract dragonflies and damselflies. To learn more now, call Ralph Rogers, EPA, at 206-553-4012


Dragonflies, Living Flashes of Light, Part II
by Ralph Thomas Rogers, EPA’s resident dragonfly expert
In the spring issue of WaterTalk, Ralph Thomas Rogers explained the life history of dragonflies and damselflies. Here in Part 2, he tells how to create habitat for them—and a cool summer oasis for your landscape!

Creating a Dragonfly-Friendly Pond

Last issue, I presented a general Odonate (dragonflies and damselflies) life history. For those of you who have been inspired and those who are already avid Odonate watchers, here are tips for making backyard or farm ponds more Odonate friendly. If you do not have a pond, I have included references for pond construction at the end of this article.

1. For greater species diversity it is recommended that an Odonate pond have a minimum surface area of 40 square feet (i.e. a circular 7-foot diameter pond or 8-foot by 5-foot oval pond).

2. To attract more kinds of our most common Odonates, your pond should hold water at a fairly constant level year-round. At the same time, different dragonfly nymphs prefer different conditions, so the depth of the pond should vary by providing a shallow sloping edge. For milder climates, the maximum depth should be a minimum of 2 feet deep. In colder climates where the pond might freeze, it should be at least 3 feet deep. Deep areas also provide refuge where nymphs can be safe from some predators (i.e. raccoons).

3. Odonates are most active on warm, sunny days. Make sure the pond has some sunny spots where they can roost and warm themselves. This may require periodic removal of tall vegetation. A few large, light-colored, flat rocks and logs along the pond margin also provide good basking sites.

4. The pond bottom should be ‘mucky’ mud and sand (allow some organic debris such as leaf litter to collect) to provide egg-laying habitat for some species of Odonates. This bottom habitat is also essential for those Odonate nymphs that burrow.

5. Although Odonates don’t require plants as a source of food, wetland and aquatic plants are still an important part of their habitat. It is best to stock your pond with a variety of native plants that can be found growing naturally in your region. 6. Avoid the use of chemicals such as fertilizers, herbicides or insecticides in the pond or in areas that drain toward the pond.

7. Do NOT stock the pond with fish!

8. Finally, consider adding a bucket of waterfrom a natural pond once a year as a source of microorganisms that are important for a healthy pond ecosystem. Make sure that ‘natural’ pond you from which you get that bucket doesn’t have invasive species that could contaminate your pond.

Happy Odonate Watching!

Select references for Dragonfly watching in Region 10:

1. Cannings, Robert A. 2002. Introducing the Dragonflies of British Columbia and the Yukon. Royal British Columbia Museum, Canada. [ISBN 0-7726-4637-6]

2. Dunkle, Sidney W. 2000. Dragonflies Through Binoculars - A Field Guide to Dragonflies of North America. Oxford Univ. Press, NY. [ISBN 0-19-511268-7]

3. Paulson, Dennis. 1999. Dragonflies of Washington. Seattle Audubon Society, WA. [ISBN 0-914516-15-9]

Select references for planning and constructing wildlife ponds:

1. Link, Russell. 1999. Landscaping for Wildlife in the Pacific Northwest. Univ. of Washington Press, Seattle. [ISBN 0-295-97820-1]

2. Weston, Shann, Janice Richardson and Susan Adams Gunn (eds.). 2001. Naturescaping-A Landscaping Partnership With Nature, 3rd Edition. Oregon Dept. of Fish & Wildlife, Portland.

For more information about dragonflies and damselflies, contact Ralph Thomas Rogers at 206/553-4012 or For more general information about Beneficial Landscaping, contact Elaine Somers at 206/553-2966 or, or visit the website at


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