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GARDEN TIPS – Written by Marianne Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Published September 4, 2016

It was never a matter of “if” the Japanese beetle would reach the Pacific Northwest, it was a matter of “when” it would get here. That could be now. Numerous adult beetles have been trapped and found eating on roses and other plants in Portland, according to the Oregon Department of Agriculture (ODA). ODA says that this suggests “a breeding population of the non-native insect has been established.”

Uh oh! This is terrible news for gardeners and growers. A University of Kentucky publication says that “the Japanese beetle is probably the most devastating pest of urban landscape plants in the eastern United States.”

I am willing to bet that if you migrated to this area from the eastern part of the US, you already know too well why a Japanese beetle infestation is scary. As a pest, this rather pretty beetle packs a double whammy. Its grubs feed on grass roots and can be very damaging to lawns. The extremely voracious adults are omnivorous, feeding on a wide variety of plant hosts including roses, ornamentals, trees, shrubs, fruit, and vegetables, often devouring the upper sides of plant foliage, leaving only the skeleton of veins and midribs behind.

The Japanese beetle is one of the scarab beetles and could be considered attractive if you like beetles. The adult beetle is almost ½ inch in length with metallic copper wing covers and clubbed antennae. The head and thorax in front of the abdomen are metallic green. Along the sides of the abdomen are hairy patches that look like white spots.

Like so many damaging insect pests, the Japanese beetle is an alien, coming here from Japan. It was first identified in the eastern US in 1916 and it became established in all the states east of the Mississippi, except for Florida, by 1998.

Besides its rapacious appetite, this beetle’s propensity for aggregating on plants can lead to rapid and complete defoliation of a plant. Japanese beetle-damaged plants emit volatile chemicals that bring more beetles to the party. In addition, the unmated females emit a pheromone to attract even more hungry beetles. Once done with one plant, they move onto another.

Thankfully, there is only one generation of Japanese beetles a year, but with each adult female laying from 40 to 60 eggs, populations can build quickly. Control with pesticide applications is aimed at both the adults on plants and their grubs in the soil. You may see Japanese beetle traps advertised for their control, but university research indicates that the traps are effective in monitoring for the beetle’s presence, but not for control. In fact, the traps can result in more of the beetles finding your yard and causing damage.

Over the years ODA has been working to contain and eradicate any Japanese beetle infestations that they have detected. They believe that the origin of these infestations are air cargo carriers coming in through the Portland International Airport. ODA estimates that the current infestation has been present for more than a year without detection. Right now they are trying to pinpoint where the breeding population is located so they can treat the infestation next year.

For us in Washington, it is good to know that the Washington State Department of Agriculture (WSDA) has been on the watch for the Japanese beetle and has been conducting trapping each year since the mid-1980s to make sure they have not become established anywhere in the state. So far, WSDA has not had to conduct eradication measures on a breeding population yet. I hope it stays that way.


GARDEN TIPS – Written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Published July 24, 2016

This week I was out weeding in my garden and noted considerable notching caused by root weevils on the leaves of various plants. Root weevils are a common pest in area home gardens but the adult weevils are seldom brought to the Extension office for identification. That is because they are nocturnal, feeding late at night and hiding during daylight hours on the undersides of leaves or beneath debris on the ground. However, you do not have to see one of the critters to know that they are at fault. Root weevil feeding causes characteristic scalloping or small semi-circular irregular notches along the leaf margins.

While some insects feed only on certain species of plants, roots weevils are not as selective. In home gardens they tend to show a preference for rhododendron, lilac, forsythia, peony, rose, euonymus, Japanese holly, blueberries, and strawberries, but they will chow down on over 100 other species of plants. Along with their distinctive notching, another sign of their presence are black fecal deposits found on the undersides of notched leaves.

Because there are at least 16 species of root weevils found in Washington, adult weevils vary in size from 1/8 to 1/2 inch long and in color from black to brown or gray. Based on research done by Sharon Collman, WSU Extension Entomologist, black vine, obscure, and strawberry root weevils are very common in western Washington, but the lilac root weevil is dominant in eastern Washington landscapes and gardens.

So what makes a weevil a weevil? Weevils are a specialized type of beetle. They are somewhat oblong in shape and have hard, crunchy outer wings. What sets them apart from beetles is their elbowed antennae and their specialized mouth parts that look like an elongated snout. Also, the inner wings of most weevils are not well developed, leaving them unable to fly.

So what makes a root weevil a “root” weevil? The creamy-white C-shaped legless grubs or larvae of root weevils eat plant roots. They start out by feeding on fine roots and then may move onto larger roots and even the crown or base of plants. Leaf notching caused by adults is primarily just cosmetic damage, but heavy feeding on the roots by larvae can kill plants.

One control strategy is to avoid introducing root weevils into your garden and landscape by inspecting plants before you buy and avoiding any with the characteristic notching. Root weevils cannot fly. To get from here to there they have to walk or hitch a ride on infested plants, soil, or plant litter.

Once root weevils get started in a yard or garden, it is hard to get rid of them. There are some home garden insecticides available for control of the adults, but generally these materials are not very effective. If you do try chemical control, apply sprays at night between nightfall and midnight when the adults are feeding.

WSU Extension recommends that gardeners manage root weevils by hunting them down after dark. No, I am not kidding. Place sheets or box tops under your infested plants and then go out late at night and shake the branches. The weevils will drop onto the sheet where you can collect and dispose of them. Do this on successive nights until you are not getting any adults dropping off the plants. (You may want to warn your neighbors about this so they do not call the police.)

Another method of control is the application of beneficial nematodes to the soil when the larvae are present. The nematodes are applied as a drench to moist soil when the soil temperature is above 55 degrees. Because of climatic conditions in our regions it may be difficult to effectively control root weevils with nematodes, but some local gardeners indicate they have worked for them.

For more information on the biological, cultural, and chemical control of root weevils go to:


GARDEN TIPS – Written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Published July 3, 2016

It is simple, I grow flowers in my garden because they are pretty and colorful. It is very disappointing when insects damage or destroy these blossoms. Here are three dastardly pests that are significantly impairing beautiful blooms in my garden.
Thrips: Western flower thrips cause damage to roses and a variety of other flowering perennials. Thrips are very tiny, straw-colored insects that feed on flower petals, often before the buds even open. They use their rasping mouths to scrape at plant tissues and suck up the liquids that ooze out. Their feeding causes streaks and blotches on the petals. If damage is severe, the flower buds may fail to open.
Thrips are difficult to control because their populations build up very quickly. Prune off and dispose of badly infested flowers and buds. Eliminate plant litter and weeds in and around the garden. Avoid using pesticides that kill thrips predators, like lady beetles and lacewings, or that harm bees visiting the flowers. If you decide to apply an insecticide, apply it directly the buds and blooms. Repeat applications are likely to be needed. For effective insecticides, go to:
Tobacco Budworm: The tobacco budworm is devouring all the buds on my petunias, including my beloved Wave petunias, before they even have a chance to open. Aargh! The few flowers that are able to open, are riddled with holes. The adult of the tobacco budworm is an unremarkable greenish-brown moth about ¾ inch long. Like many moths, it is nocturnal, flying, mating, and laying eggs at night starting in late spring to early summer.
On petunias the moths typically lay their eggs on the leaves, but on geraniums they deposit them directly on the flower bud clusters. As soon as the eggs hatch, the little larvae immediately get to work eating flower buds. They will also eat holes in leaves, especially when there are not many flower buds left. Along with the obvious holes in flower petals, buds, and leaves, they deposit their telltale small black frass (poop) on the leaves.
The larvae are hard to detect because young larvae are yellowish-green in color and blend in well with the foliage. More mature larvae vary in color from green to brown, tan, or purple. During the day, the larvae tend to hide in the soil at the base of the plant and then venture out at dusk to feed. When using hand picking for control, look for them at dusk.
As their name infers tobacco budworm is a pest of tobacco, but it also feeds on many other hosts, such as roses, snapdragon, zinnia, verbena, chrysanthemum, marigold, and sunflower. However, its preferred hosts are petunias and geraniums.
Sunflower Moth: The larvae of the sunflower moth also attacks garden flowers. Its hosts are sunflowers and other members of the same family such as daisies, zinnia, coneflower, and cosmos. The larvae of the sunflower moth feed on the flower centers, eating the developing seeds and leaving webbing and frass .
Most home garden insecticides are ineffective against both the tobacco budworm and the sunflower moth. For effective insecticides go to:
When using insecticides for control of tobacco budworms, apply them as soon as feeding damage is noticed. For sunflower moths, apply them when the flowers start to bloom.
I do not like using insecticides in my garden, especially on flowers that are visited by bees and other pollinating insects. As a result, I have switched to plants planted for the colorful foliage, like coleus and sweet potato, but I just cannot give up my petunias!


GARDEN TIPS – written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written December 6, 2015

There are two types of insects found in homes that I hate, flies and ants. Flies are my nemesis in the fall, entering the house when the door is open and then bothering me. While these flies look like houseflies, they are probably face flies, a pest of livestock. Adult face flies feed on the moisture around the eyes, noses, and mouth of livestock and reproduce in their manure. Yuck!

A couple of face flies inside the home are a nuisance, not a serious problem. Once cold weather prevails, their chance entrance into the house ceases. However, they can continue to be an annoyance if there is a significant outdoor population that overwinters within outside house walls or in attic voids. This more often happens in rural areas where there is livestock raised nearby.

If the flies do overwinter within the walls, some face flies may continue to appear indoors through the winter months when sunshine warms the house walls. The best management for a face fly problem is excluding them from the home with screening and by caulking any openings to the outdoors.

There are some other types of flies that may become a nuisance in homes. Fruit flies are one of the most common. Fruit flies are brownish in color with bright red eyes. These little flies are usually found flying around overripe or decaying fruit or veggies being stored inside the home and they are also attracted to wine, beer, and sugary drinks.

Fruit flies are easy to control by simply getting rid of overripe produce and storing ripe fruit in the refrigerator when possible. Also, rinse out any empty food and beverage containers being stored indoors for recycling. The liquids in these containers ferment and provide a great place for fruit flies to breed.

Moth flies, also known as drain flies, are often mistaken for fruit flies. A close reveals that they are tiny (1/5 inch long) hairy flies resembling moths. They can breed in the decaying organic matter and slime found in the drains of sinks and tubs, garbage disposals, and dishwasher food traps.

One step in control is to keep organic materials from getting into drains by using drain baskets or filters. Chemical drain cleaners may or may not remove the slime in a drain. If not, you will need to manually remove it using a brush or use a biological drain cleaner that contains enzymes that digest slime and organic debris. Also, clean your garbage disposals and dishwashers as recommended by the manufacturer.

Finally, fungus gnats are another nuisance fly found inside homes. These are minute (1/8 inch long) blackish flies. They breed in decaying plant matter and often arise from houseplant potting mixes that are kept overly moist. Potting mixes that contain undecayed organic materials from compost provide an excellent breeding ground for fungus gnats.

At this time of year holiday plants, such as poinsettias, may be a source of fungus gnats, especially if adequate drainage is not provided. The best bet for controlling the problem is to keep the potting mix of house plants slightly moist, not wet. Also, make sure your plants have good drainage and pots are not “sitting” in excess water.

All these flies can be a nuisance. Aerosol pesticide sprays labeled for indoor use will kill the ones flying about when you spray, but they can pose a health risk to you and your family. The real key to control is determining the type of fly and then using the right control measures to get rid of them.


GARDEN TIPS – written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written August 13, 2015


Remember a few weeks ago when I talked about the elm seed bug, a new invasive insect getting in area homes? Now a number of home owners are finding another bug inside their homes. The masked hunter bug is not new to our area, but usually only one or two are brought to me for identification each year. However, I have recently been seeing an increasing number of them.

The masked hunter bug is one member of a group of bugs known as “assassin” bugs. Coming here originally from Europe, the masked hunter bug is not native here, but it is common throughout the US. As a true bug, the masked hunter has an elongated shield-shaped back with an “X” pattern on its back created by its folded wings. The 3/4 to 1 inch long adult masked hunter is a shiny brown-black color with no colorful markings. The young nymphs (immature stages) look similar, but often “mask” themselves by covering their bodies with dirt and dust particles.

You will probably not notice another important physical characteristic, its short beak or “proboscis” tucked under its body. When feeding this beak allows it to stab, paralyze, and suck out the body fluids of its prey. When inside a home masked hunters are seeking food which can include a variety of insects, including bed bugs, bat bugs, and swallow bugs. They are effective “assassins” because they are nocturnal, hiding during the day and coming out at night looking for food. In addition, the dusty coating of the nymphs is great camouflage.

While they are considered beneficial because they eat other insects, masked hunters are not benign and should not be handled. Its bite can be painful and has been compared to a wasp or bee sting and may result in some swelling. While occasionally a masked hunter may bite if unprovoked, most human bites are made in self-defense.

It may be reassuring to know that masked hunters tend to travel alone wandering from one place to another. If you do not have a large number of insects in your home, you are not likely to encounter one or more masked hunters. While “beneficial” they should not be considered an effective method of pest control. Carefully get rid of any you find indoors.

To prevent more from being attracted to your home, look for any other possible insect populations and control them. Make sure you do not have any swallows or bats roosting in or near your home. Thoroughly clean and keep clean places the masked hunter can hide, such as under beds, along baseboards, in corners, or any place else dust collects.

Outside, tighten up your house with caulking if needed. If you leave outdoor lights on at night, change to low pressure sodium lights. Research indicates that yellowish sodium lights attract fewer insects and spiders than other types of lighting.

Another type of assassin bug found in the US is the conenose or “kissing” bug. These bugs feeds on the blood of mammals and the kissing bug’s bite and can transmit Chagas disease, caused by a parasite, to humans, dogs and small animals. This disease, primarily found in the Southwest and Central America, is not transmitted by masked hunter bugs and is not found in our region.

I wonder what insect will be “bugging” us next?


GARDEN TIPS – written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written July 9, 2015


I have several colleagues who are entomologists. They are quick to teach novices like me that all bugs are insects, but all insects are not bugs. “True” bugs belong to the order of insects called Hemiptera and have several characteristics in common. One easily recognizable shared characteristic is a shield-shaped back that is created by their folded front wings. This also creates a triangle shape or “X” pattern on their backs.

Another common characteristic is their highly modified mouth or “proboscis.” It is a long nonretractable hardened tube or “beak” that allows them pierce plant parts and suck out plant or animal fluids. Plant bugs feed on a variety of plant tissues, but seed bugs are a specialized group of plant bugs that feed on the seeds of plants, enabled by their exceptionally long proboscises.

Seed bugs are not a concern in our yards, gardens and homes because they only feed on the seeds of plants. They do not attack humans and do not damage plants. However, they do become bothersome when their numbers become exceptionally large or when they migrate into homes in search of an overwintering spot in the fall or sometimes during the summer for protection from the heat.

Boxelder bugs are a well known seed bug that are often a major annoyance in our area. With their ½ inch long black body, black legs, and bright orange-red markings and “V” on their back, they are easy to identify. While they will sometimes feed on other trees and shrubs, they primarily attack the seeds of boxelder and other types of maple.

New on the local scene is a much smaller, nondescript seed bug, the elm seed bug (ESB). It is brown and about 1/3 inch long. If you look very closely (it is small) you can see lighter colored bands around the edge of the wings and a small black triangle on its shield-like back.

With greater magnification, on the underside of an ESB’s body you would note a long beak at least 1/3 the length of the body. This beak allows it to feed on its primary source of food, elm seeds. They certainly can find plenty of food in our region with the large number of invasive Siberian elms (Ulmus pumila) that produce copious seeds.

The ESB was just discovered in our area last fall when Dr. Mike Bush, WSU Extension Entomologist, confirmed its identity. The ESB is considered an exotic invasive pest and was first discovered in the U.S. in 2012 in Idaho. This summer it is being noted in large numbers here.

Pesticides are of little value in controlling ESBs and boxelder bugs in and around the home, but a perimeter spray application of pesticide may help decrease the population. Extension experts, like Bush, recommend pest-proofing your home by caulking cracks, plugging potential points of entry, and repairing screens instead of using pesticides. Also, cover outdoor vents to the home with mesh screening that allows for air movement but is fine enough to keep the bugs out.

Both these bugs have an unpleasant stinky odor that is released when crushed. This odor can “stink” up an indoor vacuum, so use a shop-vac inside and outside the home when vacuuming them up. Before starting, add some soapy water to the shop-vac canister to drown the bugs as they are sucked up and empty it immediately when you are done.

So, what is bugging you?

Borers Attack Stressed Local Trees

GARDEN TIPS – written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written June 18, 2015

The discovery of holes in a tree’s trunk or branches usually means it has been the victim of a boring insect attack. While it is alarming to discover an increasing number of trees with significant borer damage, it is not unexpected. Most borers take advantage of trees weakened by drought stress, injury, insects, or disease. Several years of extremely dry winters along with last summer’s extreme heat has stressed local trees and shrubs, making them vulnerable to attack. Some of the dastardly culprits attacking local trees include the:

Ash Borer (a.k.a lilac borer) – The adult is a moth that looks like a yellowjacket. It primarily attacks ash, lilac, and privet. The moth lays its eggs on the bark. They hatch into small larvae that tunnel into trunk and branch wood, weakening it. The larvae pupate and emerge from the tree in May or June leaving noticeable 1/4″ exit holes.

Redheaded Ash Borer – The adult is a “longhorned” reddish brown beetle with an elongated body and long antennae. It also resembles a yellowjacket because of the yellow to white horizontal bands on its back. While called an “ash borer” it attacks a wide variety of trees including ash, linden, oak, and others. Like many other borers, it lays its eggs on the bark of stressed or dying trees. These hatch and then eat their way under the bark and tunnel into the wood as they mature. There may be more than one generation of these borers a year with adult beetles emerging from spring through summer and leaving 1/4″ exit holes.

Bark Beetles – There are a number of different types of bark beetles and one or more of these are attacking local stressed arborvitae and other evergreens. Typically, the adults are little, .08″ long, brown beetles. What they lack in size they make up for in number. They feed directly under the bark of trees and shrubs, creating serpentine paths as they eat. Their feeding can girdle trunks and branches, cutting off the tree’s access to water and nutrients. Their exit holes are pencil-point sized.

Other borers that commonly attack landscape trees in this area are the bronze birch borer, the peach borer, and the locust borer.

Unfortunately, pesticide applications are not very effective for borer control in attacked and dying trees. Sprays made to the bark surface will not kill any borers residing under the bark or within the wood. For sprays to be effective they would need to be applied when the adults emerge. Timing of sprays is critical and they may need to be reapplied if the insect emerges over a span of several months or has several generations a year.

There are some systemic insecticides that are applied as a drench to the base of trees and taken up into plant tissues. These are only effective on some flatheaded borers, like the bronze birch borer, that spend most of their time feeding in tissue just beneath bark. They are not effective in controlling borers that eat mostly in tree wood.

WSU Extension experts indicate that the best control for any borers is to keep your trees healthy and vigorous to prevent attack. This is sage advice, but too little too late for attacked and dying trees.

Spray Fruit Trees Now To Keep Worm Free

GARDEN TIPS – written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written May 7, 2015

This spring, temperatures have gone back and forth between warmer-than-normal and cooler-than-normal. Because of an early start to the growing season and the cumulative warm weather, our plants and their pests are a bit ahead of schedule.

Two insects that have already emerged are the western cherry fruit fly (WCFF) that attacks cherries and the codling moth (CM) that attacks apples, crabapples, and pears. If you have a cherry, apple, pear, crabapple, flowering pear, or a fruit-producing flowering cherry, you should have already applied an insecticide recommended for control of these pests. If you have not started a regular spray schedule, start as soon as you there is calm weather!

Even if you do not care about harvesting the fruit or if the tree is an ornamental tree susceptible to these pests, you are required by law in Benton, Franklin, Walla Walla, and Yakima counties to control them. The reason for the law is because infested backyard fruit trees can serve as a source of infestation for nearby commercial orchards, causing the orchardists to apply more pesticides or risk having their fruit being rejected due to wormy fruit.

I cringe when I see fruit trees, particularly cherries, apples, and pears, offered for sale at local big box stores and nurseries. Would-be or novice backyard fruit growers are often unaware of the extra work fruit trees require, including regular pesticide applications to control insects, like WCFF and CM, and diseases.

There are some organic insecticides available for control of WCFF or CM, but there are practically no non-chemical strategies. However, homeowners can make it easier to apply sprays by planting dwarf trees and then pruning them to keep the trees at a more manageable height of 10 to 12 feet. Keeping trees at this height will also make it easier to harvest fruit. However, annual pruning means even more work for backyard fruit growers.

GARDEN NOTE: Do not assume a “dwarf” tree will stay small without pruning. Dwarf is a relative term. Fruit trees labeled as “dwarf” may still grow to a considerable size. Check the label for the potential mature height of the tree. A “dwarf” or “semi-dwarf” apple could still reach a height of 15 to 20 feet or more.

Earlier I mentioned that home gardeners are required to keep fruit bearing ornamental crabapple, flowering pear, and flowering cherry trees free of WCFF and CM. Codling moth will even attack the small fruit of flowering pears and crabapples so regular spraying is required to keep these trees “worm-free.”

Japanese flowering cherry trees do not produce fruit, but they are grafted onto a rootstock that will produce fruit if allowed to grow. If these trees are allowed to produce fruit, you are required to keep them worm-free or you might want to remove them because they have lost the beautiful flowers and form of the Japanese flower cherries originally planted.

If you must grow fruit trees consider planting plums, apricots, or peaches which generally do not require regular pesticide applications to keep their fruit free of worms. However, these fruit trees are prone to a number of fungus diseases which will require spraying and again more work to keep the trees healthy and the fruit blemish free.

If you are growing any type of fruit tree and need to know what sprays are needed and when they should be applied, contact the WSU Extension office at 735-3551 for a Home Orchard Pest Management Chart. You can find more information about WCFF at  and CM at


GARDEN TIPS – written by – Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

published – December 19, 2014

Winter is a great time for gardeners to catch up on their reading. If you do not already have a stack of books waiting for you, here are a few suggestions for your winter respite.

Life Histories of Cascadia Butterflies by David G. James and David Nunnallee could be classified as a ‘coffee table’ book because of all the beautiful color photographs of not only adult butterflies, but also each stage of their life cycle. You might not think of butterfly caterpillars as attractive, but this book reveals their unique beauty.

This comprehensive volume was ten years in the making and covers the life histories of the 158 butterfly species found in British Columbia, Washington, northern Idaho, and northern Oregon. Gardeners, hikers, amateur entomologists, and natural history buffs should not miss this book. James and Nunnallee also cover the biology, ecology, and rearing of each butterfly species included in the book.

A botanist at heart, I am intrigued by the book, The Drunken Botanist. Few botany books make it to the New York Times Bestseller list, but this one written by Amy Stewart, is a bonafide hit. It is subtitled ‘The Plants That Create the World’s Great Drinks’ and focuses on the herbs, flowers, trees, fruits, and even fungi that humans have used to make alcoholic brews and spirits. This book is said to be a mix of ‘biology, chemistry, history, etymology, and mixology’ and includes fifty cocktail recipes as well as growing advice on many of the plants used in the recipes.

This is not Stewart’s only book with an intriguing title. She is also author of Wicked Bugs – The Louse that Conquered Napoleon’s Army & Other Diabolical Insects and Wicked Plants – The Weed That Killed Lincoln’s Mother & Other Botanical Atrocities.

Next on my list for reading is any issue of Green Prints – The Weeders Digest, but I would suggest subscribing and starting with the 100th issue of this literary gardening magazine. I recently received a copy and it reminded me of this wonderful little quarterly magazine. The editor started the magazine 25 years ago with the intent of getting to the human side of gardening, not the how-to of growing plants. In any issue you will find sweet short stories, heart-warming tales, anecdotes, pretty artwork and poetry about gardening that will make you laugh, smile, or cry. It will certainly cheer the gray winter days. To subscribe go to:

If you want to make the most of these winter months, you might want to study one of the best references available for gardeners on the topic of pruning, American Horticultural Society Pruning and Training by Christopher Brickell and David Joyce. This book is subtitled ‘The Definitive Guide to Pruning Trees, Shrubs, and Climbers.’ The most recent edition was revised and updated in 2011. Dr. Ray Maleike, retired WSU Extension Horticulture Specialist, recommends this book to gardeners with pruning questions. Available only in paperback, it costs less than $20. Another good paperback tome on pruning, An Illustrated Guide to Pruning by Edward F. Gilman, costs over $100, but it is rich with diagrams and illustrations. If you read all 496 pages, you will be a pruning expert!

Published: 12/19/2014 12:37 PM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
published – SEPTEMBER 5, 2014


Have you been wondering why so many local elm trees are looking so sick? It is because large numbers elm leaf beetles have been dining on our elms this summer. Most elm owners do not notice elm leaf beetle damage until they are done feeding for the season. An adult beetle is about 1/4 inch long, olive-green, with two dark longitudinal stripes down its back. The larvae are yellowish green with black stripes and spots.

Both the adults and larvae of elm leaf beetles feed on elm leaves. Adult beetles eat holes in the leaves and the larvae skeletonize them, leaving only the veins and the waxy top layer of the leaf behind. The leaves then turn brown. If the population is large enough, they can defoliate a large tree by the end of summer.

Some species of elm are resistant to the elm leaf beetle. However, the Siberian elm (Ulmus pumila), the predominant elm found in many area landscapes, is not resistant. Siberian elm is a fast growing, large tree that reaches a height of 50 to 70 ft.

Dr. Michael Dirr, renown tree and shrub expert, says that the Siberian elm is “one of, if not, the world’s worst trees” because it is so messy and has brittle wood. Siberian elms produce prolific amounts leaf, branch, and seed litter, plus the tree is prone to limb breakage in wind and ice storms.

Add to long list of Siberian elm’s negative traits, the defoliation caused by elm leaf beetles. Because they are such tall trees, insecticide applications to control the beetles must be performed by licensed applicators. This is a costly service but may be worth it if the tree is of high value to the owner and if attacked repeatedly.

A less costly pesticide application is an insecticide drench applied to the soil at the base of the tree. However, this must be applied in late winter or early spring (before knowing if beetles will a problem or not) to be absorbed by the roots and moved systemically to the top of the tree. This movement can take four to six weeks or more and is dependent on water being applied to the soil regularly after application.

Elm leaf beetle populations have a tendency to fluctuate from year to year. In fact, it has been a number of years since we have experienced a severe elm leaf beetle outbreak in this area. Many insect populations tend to ebb and flow because of environmental conditions, the availability of food, and natural enemies. University of California experts note that more overwintering adult elm leaf beetles tend to die if winter weather is relatively warm or wet. Just because the beetles are causing damage this year, does not mean they will be a problem next year.

At the end of summer adult elm leaf beetles look for protected places to overwinter. “Protected places” include wall voids of nearby homes. In the spring they come out of hibernation and move back outdoors. However, some get lost and find themselves indoors. Vacuuming is the best method of control along with caulking cracks and wall voids to prevent their entry into the house in late summer.

I am wondering if the elm leaf beetles will be plentiful again next year, maybe not if we have a mild winter.

Published: 9/5/2014 12:32 PM

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