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ON THE WATCH FOR JAPANESE BEETLES

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.

ROOT WEEVILS IN THE GARDEN

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: http://insect.pnwhandbooks.org/small-fruit/strawberry/strawberry-root-weevil.

FLOWERS ATTACKED BY DASTARDLY INSECTS

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: http://hortsense.cahnrs.wsu.edu/Search/MainMenuWithFactSheet.aspx?CategoryId=1&SubCatId=2&PlantDefId=33&ProblemId=568
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: http://hortsense.cahnrs.wsu.edu/Search/MainMenuWithFactSheet.aspx?CategoryId=1&SubCatId=2&PlantDefId=171&ProblemId=827
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!

WHAT’S BUGGING YOU?

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

WHAT’S BUGGING YOU?

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 http://cru.cahe.wsu.edu/CEPublications/FS125E/FS125E.pdf  and CM at http://cru.cahe.wsu.edu/CEPublications/FS120E/FS120E.pdf

STINK BUGS CAUSE SPOTS ON TOMATOES

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

The brown marmorated stink bug that has been plaguing the eastern part of the US damaging crops and invading buildings, but the stink bug that’s a problem for some area gardeners is a green stink bug. It’s feeding is causing yellowish to whitish cloudy spots all over tomatoes infested with stink bugs. Just beneath the skin of a ‘cloudy spot’ are clusters hardened white spongy cells. While still edible ,this makes the fruit difficult to peel and impairs their eating quality.

This is the time of year stink bugs residing in nearby weeds move to the garden to pierce ripening tomatoes. Scientists disagree exactly what causes the spots, but generally it’s believed that they inject a toxin into the fruit when they pierce it for its juices. There are a variety of different stink bugs that can cause this damage, but the one gardeners are bringing to me are bright green ‘Say’ stink bugs. These shield-shaped bugs are about .5 inch in length with orange spots at the base of the triangular back. The nymphs or young stink bugs are blackish in color. There are also brown stink bugs that can be found in the garden.

According to University of Utah bug experts, one stink bug per plant could cause 5-10% damage. That means that it doesn’t take excessive amounts of stink bugs to cause significant injury to garden tomatoes. If suspect you have a stink bug problem, the Utah expert indicated that you can find the culprits ‘by vigorously shaking the plant and examining the dirt beneath for fallen insects.’ Another hint that stink bugs are present is the brown liquid frass (yuck) that they leave behind as dried spots on the leaves and fruit where they’ve been feeding.

If you have a stink bug problem, control will not be easy. That’s because stink bugs don’t reside in the garden, but in weedy areas nearby, such as fence rows and ditches. Control involves eliminating weeds to prevent their overwintering and keeping weeds down during the gardening season. Potential overwintering hosts include Russia thistle, plantain, mullein, mustards, mallow, dock, blackberries, legumes, as well as other weeds.

In addition to good weed management, pesticides can be utilized for control but you should not only spray the vegetable garden, but also weedy areas that may be serving as stink bug havens. If you’re gardening organically, try using insecticidal soap sprays. Keep in mind that the soap sprays only affects the bugs to which it directly applied, so you’ll need to reapply soaps regularly.

There are also garden insecticides containing bifenthrin, permethrin, cyfluthrin, imidacloprid, or carbaryl that are effective against stink bugs. Be sure to find a product labeled for use in the vegetable garden, particularly tomatoes. If you use them on other vegetables or fruits be sure that they’re also listed on the label.

Some of these garden insecticides are highly toxic to bees. Be sure to follow all label directions and take the precautions needed to protect bees, wildlife, and yourself. Always check the label to find out how many days after spraying you must wait before you can safely harvest and consume (or preserve) the fruit. This may be labeled as ‘days to harvest’ or ‘pre-harvest interval’.

Finally, to answer another question that may be on your mind… yes, stink bugs do really stink. As a defense mechanism they have small glands on their body that emit a foul smelling liquid when threatened or mistreated. Eat one in a raspberry or hand squash them in the garden, and you’ll find out that they come by their name honestly.

Published: 8/3/2012 1:42 PM

NEWER PESTICIDES FOR FIGHTING INSECTS

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

Due to environmental concerns, over the last 10 to 15 years gardeners have lost the use of many familiar ‘tried and true’ garden insecticides, such as diazinon. This left gardeners wondering if their only recourse was surrendering when insects attacked the garden. For devoted gardeners, surrender was not an option and now other options are available to help.

One earth-friendly effective biological pesticide is spinosad. Spinosad, derived from the fermentation by-products of a soil microorganism, must be ingested by insects to be effective. Once ingested, it attacks the insect’s nervous system, causing rapid over-excitation and death in one to two days.

Since it has to be eaten to be effective, spinosad products work best against leaf feeding insects like caterpillars, loopers, leafminers, thrips, sawflies, and leaf beetle larvae. It’s also effective against fruit flies, spider mites and fleas (when used as an oral flea medication) on dogs. It does not appear to harm non-leaf feeding beneficial insects such as ladybugs, green lacewings, and predatory mites.

Spinosad can be found in several home garden product lines including Bonide Captain-Jack’s Deadbug Brew, Monterey Garden Spray, and Bulls-Eye Bioinsecticide.

Neonicotinoid pesticides, a newer category of insecticides, have also become available to home gardeners. Neonicotinoid pesticides are the synthetic versions of the highly toxic natural insecticide, nicotine. Like nicotine, they work by causing excitation of an insect’s nerves, then paralysis, and eventual death.

One of the neonicotinoids that many gardeners know well is imidacloprid which is a systemic material that’s applied to soil and taken up by the roots of trees and shrubs. Imidacloprid has a long period of residual activity and is considered very effective against sucking insects, whiteflies, turf insects, beetles, and a few tree borers. Insects die after sucking or eating the leaves of treated plants. Applied as a drench, it allows gardeners to control insects in large trees without needing special equipment to reach the tops or worrying about wind and the resulting spray drift.

Numerous home garden soil applied systemic insecticides contain imidacloprid. Bayer Advanced products initially were the only home garden products that contained imidacloprid because Bayer held the patent. Now that imidacloprid is off patent, it’s appearing in other lines of home garden pesticides. Products include Bayer Advanced 12 Month Tree & Shrub Protect & Feed, Monterey Once-a-Year Insect Control, and Ortho Tree & Shrub Insect Control. Imidacloprid can also be found in products that are applied as sprays to plants.

A newer neonicotinoid, clothianidin, is being introduced in the some of the Bayer products, such as Bayer Advanced 12 Month Tree & Shrub Protect & Feed Concentrate, that once only contained imidacloprid. Yet another nionicotinoid is acetamiprid. It’s applied as a spray and can be found in various Ortho garden products, such as Ortho Flower, Fruit & Vegetable Insect Killer and Ortho Rose & Flower Insect Killer. It’s a systemic applied as a foliar spray for control of aphids, various other sucking insects, beetles, armyworms and other caterpillars of both ornamentals and edible crops.

These new products generally have relatively low toxicity to humans and animals, but this isn’t necessarily true with bees and other wildlife. The neonicotinoids are highly toxic to bees and are being blamed in parts of Europe for massive bee die-off. So while we gardeners may have new chemical tools available to assist us in fighting insect attacks, we should always read and follow label directions to protect the beneficial wildlife in our gardens.
Published: 2/10/2012 1:11 PM

NEW CHEMISTRY FOR CONTROLLING INSECTS

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

In the “old days” thirty years ago, gardeners were usually more concerned about killing any insect they found on their garden plants. The adage that the “only good bug is a dead bug” prevailed. Thankfully, times have changed. Most of the old chemicals have been banned because of the harm they caused to the environment or to humans. They were applied to plants as a spray and killed a broad spectrum of both harmful and beneficial insects.

Today, there are new environmentally kinder chemicals available. One relatively new material is imidacloprid (IC). There are spray and granular formulations of IC available, but it also comes in a soil drench used for treating trees and shrubs. Because it’s a systemic, IC is absorbed by the roots and moves throughout the plant. It primarily kills insects that suck on plant sap, such as aphids, but can poison some leaf feeding insects, such as root weevils and leaf beetles.

First registered in the US in 1994, IC introduced a new chemistry in pest control. It’s a neonicotinoid. It disrupts an insect’s nervous system by inhibiting certain nervous system receptors, causing paralysis of an insect’s mouth parts and leading to death by starvation. It kills both by contact (spraying the insect) and by ingestion (either by sucking of plant sap or eating leaves.) While IC is considered only moderately toxic to humans, it’s very toxic to bees and some small birds and slightly toxic to fish.

Both foliar and drench formulations of IC are available to home gardeners under the “Bayer Advanced” label. (Bayer CropScience holds the patent for IC.) The drench formulation is a boon to gardeners because it allows them to treat tall trees for aphids and some leaf beetle pests without having them sprayed by a commercial firm or trying to spray the trees by themselves. Controlling insect pests on tall trees is difficult because it requires special equipment to reach the top branches and disperses pesticide throughout the area, killing many non-target insects. The only equipment required for applying an IC drench is a watering can. The product is mixed with water and applied to the soil around the base of a tree’s trunk.

While typically called a systemic “insecticide,” IC’s chemistry is different than past systemic insecticides. It moves in the xylem, the water transporting vascular cells in woody plants. Because it has to move from the roots to the top of a tree, a drench application of IC doesn’t provide immediate protection from insect attack. It can take four to eight weeks for IC to reach its way to the top of a small tree and eight to twelve weeks to become fully effective in larger trees. When targeting spring feeding insects, such as wooly ash aphids on ash trees, an IC drench should be applied in September or early October. If you missed a fall application, try for very early spring. IC has a long residual and can stay effective in the plant for up to a year, so a fall application doesn’t mean that it won’t be effective in the spring when applied in the fall.

IC shows promise in controlling bronze birch borer and root weevils, two difficult to control pests of local landscape plants. If you have a problem with one of them, you just might want to be ready to treat your plants in late winter or early spring. If using an IC drench, follow the label directions for when and how much to apply.

Published: 1/9/2010 2:50 PM

WHAT’S BUGGING YOU TODAY

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

What’s bugging you? An entomolgist will tell you that all bugs are insects, but all insects are not bugs. “True bugs” belong to a particular order of insects called Heteroptera. True bugs have piercing, sucking mouthparts that allow them to feed on plant sap or animal body fluids. True bug adults typically have a flattened body and when at rest their wings form an X-shaped pattern on their backs.

One group of true bugs is referred to as seed bugs because they feed on the seeds of plants. Most are relatively small, no more than one-quarter to one half inch in length, with narrow, elongated bodies. There are both native and introduced species of seed bugs that feed on plants in our area. Their appearance varies from species to species, with most being an indistinct gray to brown color.

Many seed bugs give off an offensive odor when threatened or crushed and a few may even “bite” (actually they pierce the skin with their sucking mouthparts). In our area there are seed bugs that feed on sagebrush, birch and sycamore trees.

Because seed bugs can be present in large numbers in a yard and garden, they may cause concern. However, they aren’t considered a plant pest since they feed predominantly on the seeds of plants. It’s when seed bugs come indoors that they can become a problem.

This past week an area resident brought in a sample of a newly introduced exotic species of seed bug known as the tuxedo bug (Raglius alboacuminatus). His family was unhappy because a number of these tiny bugs were invading their home. Seed bugs don’t enter homes to harm people or pets or to infest food or clothing. They’re simply lost. Because the bugs are small, they easily enter buildings through small openings such as those found in vent screens, around window and door framing, and other openings.

Control is most easily achieved by vacuuming up the bugs and then disposing of the vacuum bag in the outside garbage can. Look for places they may be entering the home and try to exclude them in a practical way, such as with caulking or screening.

Stink bugs are another true bug found causing problems in local gardens. Both the Say stink bug (bright green with orange around the bottom edge) and the consperse stink bug (light brown)

are about one-half inch long, roundish and shield-shaped. While sucking plant sap, the stink bugs introduce saliva into a plant. The toxins in this saliva can cause plant reactions, such as the cloudy white spots found just beneath the skin of ripe tomatoes. Stink bugs also cause problems with their “stink” that can give an unpleasant taste to raspberries and other small fruit they feed on.

To help control stink bugs in the garden, remove nearby weeds that serve as overwintering hosts. Continue to practice good weed management during the growing season in and around the garden area. Sprays of insecticidal soap may be helpful if applied directly to the bugs when they are present. Check in the evening for them on garden plants and nearby host plants.

So is anything else bugging you?

Published: 8/15/2009 10:31 AM

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