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Gardening in Washington State

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Join the WSU Garden Team’s Pestsightings Listserv

Posted April 25, 2014

Did you know that, as a complement to the Washington State University Gardening Blog, the WSU Extension Gardening Team has also developed pest sightings LISTSERV? The LISTSERV will alert you to new pest information and other major pest news.

Japanese beetle
Japanese beetle

While we will stick to home and garden insects, diseases, weeds and vermin, the list may also interest Agriculture/Horticulture/Natural Resource researchers, educators and Master Gardeners.

To join, email: with the word “subscribe” in the subject line.

Why would you want to join yet another WSU LISTSERV? Here’s a sample of recent notices:

  • Japanese beetle news
  • Watch for mountain ash sawfly
  • Anthidium manicatum found in Granite Falls
  • Be on the lookout for brown marmorated stink bugs
  • Springtails are aggregating, etc.

Short and to the point, news you can use.

Feel free to contact Todd Murray ( with any questions.

Submitted by: Todd Murray, April 25, 2014

Do woody mulches attract termites, carpenter ants, and other pests?

Posted August 10, 2015

Many wood-based mulches are not attractive to pest insects but are actually insect repellent. For instance, cedar (Thuja) species produce thujone, which repels clothes moths, cockroaches, termites, carpet beetles, Argentine ants, and odorous house ants. In general, termites prefer higher nutrient woody materials such as cardboard, rather than wood chips.

Courtesy Wikipedia

Termites – courtesy Wikipedia

For more information on wood chip mulches, see “Using Arborist Wood Chips As a Landscape Mulch” WSU Extension Fact Sheet FS160E.

Submitted by: Linda Chalker-Scott, August 10, 2015


Yellowjackets! Ouch!

Posted October 23, 2017

Yellowjackets and paper wasps may become aroused and attack in defense of their nest when disturbed and can be pests when they build a nest on or near your house.  Nests of most species are placed underground in rodent burrows or other soil cavities and colonies attain maximum size in August and September. Worker yellowjackets, then at their peak, become pestiferous.


Common yellowjackets from trap
Photo by Dave Pehling, WSU Extension, Snohomish County

Yellowjackets may be attracted in large numbers to food at picnics, to honey bee colonies, and to garbage cans.

For additional information about yellowjacket wasps and paper wasps, see the WSU publication “Yellowjackets and Paperwasps” and “Managing yellowjackets” from WSU Pestsense,

Submitted by: Dave Pehling, Octobr 23, 2017.


European Chafer

Posted September 14, 2015

In 2001, European chafer grubs were discovered infesting lawns in New Westminster, the greater Vancouver area of British Columbia, Canada, less than 15 miles from the northernmost border town in Washington State. The risk of movement from infested areas via human activity is high.


Larvae are the damaging stage of the European chafer. They commonly prefer to feed on cereal plants like turf grasses and wheat. They have also been found feeding on the fine roots of broadleaf plants and conifers. In turf, larvae feed in the root zone up to the root crowns. Secondary pests such as raccoons and skunks peel back turf to feed on the grubs, causing significant damage to lawns.

April to May and September to October are the best times to monitor for the grubs because this is when they are the easiest to spot (i.e., at their largest stage).

For more information, see Pest Watch: European Chafer.

Submitted by Sharon Collman, September 14, 2015


Beneficial Predators of Aphids Found in Fruit Trees

Posted June 15, 2015

For nearly every plant in the home landscape, there is an aphid species that feeds on it. Fruit trees are no exception. Apples host a green apple aphid, cherries host a black cherry aphid (Myzus cerasi), and peaches and nectarines host a green peach aphid (M. persicae). While aphids rarely damage the fruit itself, they can compromise the health of a fruit tree, reduce the size of the fruit, and deposit a sticky substance called honeydew on the surface of fruit and leaves.

Green peach aphid
Green peach aphid. Photo by Mike Bush

There are many beneficial insects that graze on aphids, and in most years, these natural enemies do a fair job of keeping aphid populations in check. Beneficial insects include lady beetles, lacewings, syrphid flies, and parasitic wasps that sting and lay eggs in aphids. Learn to recognize these beneficial insects and conserve them. Many types of beneficial insects can be drawn to the home landscape by planting certain flowers in the yard, such as asters and legumes, as ground cover beneath the fruit tree. Perhaps one of the best ways to conserve these biological agents is to minimize pesticide use. Organic pesticides products should only be used when necessary to protect the fruit and maintain the health of your tree.

Lady beetle larva
Lady beetle larva. Photo by Mike Bush

For more information on organic management of tree fruit pests see the WSU Extension manual EM066E- Organic Pest and Disease Management in Home Fruit Trees and Berry Bushes by Drs. Charles Brun and Michael Bush on-line.

For more information on beneficial arthropods in the home landscape, see the WSU Extension manual EM067E- Beneficial Insects, Spiders, and Other Mini-Creatures in Your Garden: Who They Are and How to Get Them to Stay by Dr. David James on-line.

Submitted by: Michael R. Bush, June 8, 2015


Backyard Cherries without the Cherry Maggots

Posted February 9, 2015

Before planting a backyard cherry tree, homeowners should consider the challenge of pest management, especially management of the western cherry fruit fly (WCFF).

Fruit infested with the cherry fruit fly larvae, known as maggots, may have a dimpled appearance, but the maggots can still be difficult to detect when examining the surface of the fruit. However, as the maggots mature, they break the surface of the cherry and open a hole in order to breathe and exit the fruit.

cherry maggot
Sweet cherry infested with cherry maggot.  Photo by Mike Bush, WSU Extension.

There are relatively few proven strategies that homeowners can use to manage this pest. The primary non-chemical strategy to manage WCFF is to pick off every cherry from the tree at harvest. WCFF management will be considerably easier for homeowners who plant fruit trees grafted to dwarfing rootstocks. For a list of pesticides (including organic products), homeowners can access the WSU Hortsense website at .

Pruned cherry
Backyard sweet cherry skillfully and properly trained/pruned to a 10-foot height.  Photo by Fred Staloch, WSU Master Gardener volunteer.

For more information on organic management of tree fruit pests see the WSU Extension manual FS125E- The Western Cherry Fruit Fly and Your Backyard Cherry Tree by Michael Bush and Marianne Ophardt on-line at

Submitted by: Mike Bush, February 9, 2015

Dwarf Rootstocks for the Home Orchardist

Posted January 20, 2015

Home gardeners should consider using fruit trees grafted to dwarfing rootstocks. Trees grafted on dwarfing rootstocks are not only shorter, but take up far less space within the home landscape. They also tend to mature and set fruit sooner than full-sized trees. Fruit trees grafted on dwarfing rootstocks are easier for homeowners to maintain and manage pests by organic means. Dwarfing rootstocks for apple, cherry, pear, prune, and plum are available to home­owners at many home and garden centers. Some nurseries sell just the rootstocks for home gardeners who are interested in budding or grafting their own dwarfing fruit trees.

Dwarf appleTraditionally, apple trees in western Washington have been sold on semi-dwarfing rootstocks. Depending upon the vigor of the cultivar, it is not uncommon to find trees reaching a height of over 15 to 18 feet when semi-dwarf rootstocks are used. To best ensure that the total tree height will not exceed 10 feet, homeowners should select trees with fully dwarfing rootstocks such as M9, Bud 9, or M27 varieties. Full dwarfing rootstock trees are now available at independent garden centers.

The fruit on dwarf rootstock trees should be compa­rable in size to those found on semi-dwarf rootstocks. Full dwarfing rootstocks trees are not self-supporting. They require support either from a post or a wire trellis. Trees grown on full dwarf rootstocks typically bear fruit within 2 years, while trees on semi-dwarfing rootstocks may take 4 to 5 years.

Regardless of the rootstock chosen, overall tree size is best maintained by proper training and pruning.

For more information, see Organic Pest and Disease Management in Home Fruit Trees and Berry Bushes .

Submitted by Charles A. Brun, January 20, 2015


What is making tunnels in my yard?

Posted September 11, 2014

There are a number of animals that can cause damage to lawns, gardens and crops in Washington through their tunneling habits. The most common pests are moles, voles, gophers and rats. Ground squirrels in eastern Washington and chipmunks statewide also burrow but are active during the day and so are usually easy to visually identify…but what about those diggers you never see? The new WSU Extension Fact Sheet, “What is Tunneling in My Yard” will help you identify the guilty parties so you can plan your management strategy.

Fig6molehill2012 Fig7voleholeMtVernon

For more information please see What is Tunneling in My Yard? FS143E

Posted by: Dave Pehling, September 11, 2014

Praying Mantids – Defender of Home Landscapes

Posted August 11, 2014

Praying mantids are among the largest (1 to 4 inches long) and most recognizable garden predators—and they’re not fussy about what they catch and eat. They are “sit and wait” predators that pounce on any insect that comes too close, including beneficial in­sects, like bees and butterflies. The most common species in the Pacific Northwest is the European mantid (Mantis religiosa). Praying mantids are most often seen in the garden from mid-summer to mid-autumn.  After laying a number of white, hard-foam egg cases (which overwinter attached to branches and trunks), Mantids are typically killed off by the first frosts of autumn. They kill and consume a good number of pests like caterpillars and flies, but their contribution to garden pest control is usually less than their larger-than-life image.

An adult female praying mantid, Mantis religiosa, poised on potted poinsettia plant in search of its next arthropod meal.  Photo by Mike Bush, WSU Extension.

For more information on beneficial arthropods in the home landscape, see WSU Extension manual EM067E- Beneficial Insects, Spiders, and Other Mini-Creatures in Your Garden: Who They Are and How to Get Them to Stay on-line at

Submitted by: Michael R. Bush, August 11, 2014


How to Recognize and Eradicate Bed Bugs

Posted April 8, 2014

Whether it is spring fever or the opening of the Master Gardener Clinic in Yakima County, March and April tends to bring out the worst in bed bug sightings.  Since bed bugs are household pests, there should be little or no seasonality to bed bug abundance.

The saying “sleep tight, don’t let the bed bugs bite” is not just a quaint bedtime rhyme, but also a reminder that bed bugs do exist, and they require human blood meals to survive and provide for their offspring. In today’s highly mobile society, bed bugs have reestablished themselves as household pests. Bed bugs are not known to transmit human diseases, but they can cause skin welts, local inflammation, and contribute to insomnia.

Bedbug getting up close and personal with an Extension Entomologist (Photo Credit: Michael Bush)

Bed bugs have been found in homes, apartments, rental units, and even hotels throughout Washington with increasing frequency. Cimex lectularius is the most common species that feed on humans.

Management Strategies:

1) Avoid introducing bed bugs into your home. Homeowners should not acquire second-hand mattresses and upholstered furniture without first quarantining them.

2) Remove or replace any infested furniture, including mattresses, box springs, couches, and upholstered chairs, whenever possible.

3) Clean and vacuum furniture and mattresses and wash bedding weekly. This will reduce, although not eliminate, bed bug infestations.

4) Establish a barrier or space between the bed and the floor to further discourage bed bugs from climbing onto the bed (remember bed bugs are wingless and cannot fly).

5) Obtain pesticides labeled for indoor use against bed bugs. Look for an annually revised listing of these products on the WSU Pestsense website at

6) Inspect sleeping areas in rooms adjacent to the infested area since these surprisingly mobile, yet wingless, bugs can move into surrounding areas.

The incidence of bed bugs is on the rise in North America, so precautions to avoid introducing them into your home are prudent. Bring any bugs found during a home inspection or captured on sticky traps or cards to your local Extension office for identification. While there are management strategies that homeowners can take to reduce the incidence of bed bugs in an infested household, the best management strategy is to cooperate with a local pest control professional to eradicate the problem.

For more information on Bed Bugs: Recognition and Management go to

Submitted by: Michael Bush, April 8, 2014

Gardening in Washington State, Puyallup Research and Extension Center

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