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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


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

Have you checked the labels of your favorite home and garden pesticide products lately? Do you know what is in the bottle? Over the years I have noticed that marketers of major brand home garden pesticides sometimes change the active ingredients in a particular product but keep the product name the same.

Why do they do this? In some cases an ingredient was pulled off the market and another chemical was substituted for it. In other cases, a more effective ingredient is exchanged for the original or combined with the original for a better working product. In yet other cases, an additional ingredient is included to provide added value, creating a product that does more. Whatever the reason for the change, manufacturers often keep the product name the same because of their customers= familiarity with it.

For example, most gardeners are familiar with glyphosate marketed by Monsanto and sold under the trade name of Roundup Weed & Grass Killer. Once Monsanto=s patent for glyphosate expired, other home garden pesticide marketers were able to offer similar glyphosate products. To Astay in the game@ Monsanto needed to create an Aadded value@ product or one that performed better.

Roundup Weed & Grass Killer Concentrate Plus contains glyphosate and diquat as the Aplus.@ Diquat is not new. It is a contact herbicide that acts very quickly, killing weeds down to the roots within one to three days. Its quick action is very satisfying for the user, but it does not kill weed roots. Glyphosate is still a needed for killing the roots. However, an application of glyphosate alone can be less gratifying because it takes longer (three days to a week or more ) before weeds start to die.

Another Monsanto glyphosate product for home gardeners is Roundup Max Control 365. It contains glyphosate and diquat along with an additional ingredient, imazapic. Imazapic works as a pre-emergent (preventer) and post-emergent herbicide in controlling some broadleaf weeds and grasses. Imazapic provides long-term control of germinating weeds because it stays effective for several months or more.

With the added imazapic, Roundup Max Control 365 promises a full year of control. It is only for use on driveways, patios, sidewalks and gravel areas. It is not for use in landscape beds, lawns, flower or vegetable gardens, or anywhere in the root zone of desirable trees and shrubs.

Home gardeners may also find Roundup Ready-to-Use on store shelves. It is a basic home garden glyphosate product that contains pelargonic acid that acts similarly to diquat. In addition, there are Roundup Brushkiller products that contain the herbicide triclopyr along with glyphosate.

It can certainly get confusing. That is why it is important to read the label of any a pesticide (insecticide, herbicide, or fungicide) product, even if you have used it before. The ingredients and the directions may have changed. To protect your family, yourself, and plants, be sure to read and follow the label directions.

Published: 12/5/2014 11:55 AM


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

Last week we talked about ‘midnight marauders,’ garden pests that attack plants at night. This includes slugs, earwigs, and root weevils. Today let’s talk about how to manage them and limit their damage.

Many of these nocturnal pests hide in nearby weeds or under plant debris during the day, so the first step is to tidy up the garden. Get rid of hiding places in and near the garden, such as rocks, boards, clumps of dirts, and plant litter. Remove or mow tall grasses and rogue out weeds in or near the garden.

Welcome birds, spiders, ground beetles, garter snakes, and frogs to your garden. These natural predators can help keep these pests in check. Earwigs and slugs prefer damp conditions. By using drip irrigation in your garden and drying out the soil surface, both can both be discouraged.

If these simple measures fail to keep these pests in check, trapping is a non-chemical control approach to take before using pesticides as a last resort.

SLUGS: Traps are easily created with deep saucers, pie pans, or cans sunk in the ground so the edge of the container is level with the soil. Beer is added to attract slugs withing a few feet or so from the trap. The slugs crawl into the trap and and drown. Remove dead slugs daily and refresh with new beer every few days.

Slugs can also be trapped by placing boards or wet unrolled sections of newspaper down on the soil near damaged plants. Each morning lift them up and handpick any slugs hiding underneath.

EARWIGS: When earwigs have been a significant problem in your garden in past years, frequent shallow cultivation of the soil, especially early in the spring, will disrupt nests and destroy eggs.

Earwigs can be trapped in shallow tuna or cat food cans. Place the clean cans in the garden and fill them with about a half inch of vegetable oil. The earwigs climb in and drown. Make sure the level of the oil is at least one inch below the edge of the container. When full of earwigs, empty and renew the trap. Some gardeners say adding a few drops of molasses on top of the oil makes the traps more attractive to the earwigs.

Another earwig trap consists of loosely rolling up a moistened section of newspaper and securing it with rubber bands. The roll will trap more earwigs if baited with wheat germ or wheat bran before rolling. In the evening, place the moistened rolls out in the garden near damaged plants. In the morning, collect the rolls, seal them in a plastic bag and dispose of them in the garbage. Repeat this nightly for several weeks.

ROOT WEEVILS: A simple method for trapping root weevils is to place a sheet beneath each of the damaged plants in the evening. Then go out well after dark with a flashlight and shake the affected plants. The feeding weevils will drop to the sheet. Collect the weevils and drop them in some soapy water. Do this nightly until you are catching few to no weevils.

LAST RESORT: There are a number of pesticide products available for control of slugs, earwigs, and cutworms in the garden. If you’re using the product in a vegetable garden, make sure it’s recommended for use around food crops. Slug baits containing iron phosphate are effective and less toxic than other baits. Whichever products you select, be sure to read label directions. Note that baits can be attractive to pets. Follow all label precautions to avoid poisoning pets or bees.

Published: 6/22/2012 2:44 PM


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


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Last week a frustrated gardener came in and said that the spinosad pesticide product that he had purchased wasn’t doing anything to control the aphids on his roses. I wasn’t surprised. Spinosad is most effective in controlling chewing insects, such as caterpillars, leaf beetles, leaf rollers, and thrips. Aphids are a sucking insect. There are other materials that are much more effective against aphids.

While it’s sometimes hard to find knowledgeable staff at stores that sell pesticides, the pesticide label is a great source of information. It will tell you what types of plants you can use the product on, how to apply the material, and what type of pests it will control. This gardener’s spinosad container was empty so he gave us the label. Did you know that pesticide label print is so minuscule that just trying to read it can be frustrating?

If you can decipher the tiny print, you should be able to find out what pests the product will supposedly control effectively. I could find no aphids listed on the label anywhere. If the type of target pest that’s troubling your plants is not on the label, don’t buy it… even if the store clerk says it “should work.”

The label will give instructions for the amount of material to use for application and how to mix it. In addition, the label will provide you with any special precautions you should take to protect yourself, your plants, or wildlife. Even if a material is considered “organic” and relatively benign, it can pose a hazard. Spinosad, as noted on the label, is highly toxic to bees. The label warns not apply it to blooming plants.

Another part of the label that should be heeded is the minimum number of days you must wait from your last application until you harvest the fruits or vegetables. This varies from crop to crop. For example, you must wait seven days to harvest apples after spraying them with this spinosad product, but you only have to wait one day after treating tomatoes. Even if a material is designated as an “organic” material, it doesn’t mean you can eat treated crops right after application. For any type of insecticide or fungicide, check the label when treating food crops for how long you must wait.

This spinosad label also directs you as to the maximum times you may use it in one season on the same plant and the minimum days to wait before reapplying it. These are aimed at preventing insects from building-up resistance to the material.

So what should have the “frustrated” gardener used instead of spinosad to kill aphids on his roses. If he wanted to use an “organic” or less toxic material, I would recommend an insecticidal soap or neem oil product. Thorough coverage of infested plants is crucial in achieving success with these. Since this is a non-food crop, there are other non-organic, more toxic products that will also kill aphids effectively. Products containing acephate, cyfluthrin, or imidacloprid should provide good rose aphid control.

When selecting any pesticide product read the entire label, even though the print is much to small to make this easy. Make sure the pest is listed on the label. Make sure the type of crop or plant is listed on the label. Read and follow all precautions for that product’s safe use in your garden and landscape, whether the material is organic or non-organic. This will protect your garden from pests and you from becoming a frustrated gardener.

Published: 8/14/2010 8:48 AM


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


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Finding a pesticide that killed insect critters in the garden used to be easy when we had materials like diazinon and dursban, but those were the old days. Those chemicals are no longer available and now we have more environmentally friendly materials that kill insect and mite pests using different chemistry. It’s helpful to understand how they work so we can use these new chemical tools effectively in the garden and landscape.

Spinosad is a product derived from the fermentation byproducts of a naturally occurring soil bacterium. Spinosad has an interesting history that dates back to 1982 when a new bacterium was discovered by a vacationing scientist. He found it in the soil at an old rum distillery in the Caribbean. Later it was discovered that the metabolites that resulted from a fermentation process using this new bacteria had insecticidal properties. The first spinosad insecticide was formulated in 1988 and strangely the original bacterium has not been found anywhere else in nature.

As an insecticide, spinosad kills insects both by direct contact and when the insects feed on treated plants, but it’s 5 to 10 time more effective when ingested. It kills insects by causing an excitation of the insect nervous system. This results in the death of the insect within one to two days.

Spinosad is not a broad spectrum insecticide. It’s most effective on lepidopterous (moth and butterfly) caterpillars, Western flower thrips, and some beetle larvae, flies, leafhoppers and leafminers. It doesn’t seem to provide much control of aphids or true bugs. One of the benefits of spinosad is that it has low toxicity to mammals and it’s not toxic to many of the beneficial insects in the garden, such as ladybugs and lacewings. However, it is highly toxic to bees and moderately toxic to fish. Spinosad should not be applied where bees may be active. Research indicates that spinosad lasts from several days to several weeks on treated plants. For those of you with fruit trees, it can now be used on your apples to control codling moth and on cherries to control cherry fruit fly.

Home garden products that contain spinosad and are cleared for use by Washington gardeners include Bull

s-eye Bioinsecticide, Green Light Lawn & Garden Spray Spinosad, Monterey Garden Insect Spray Easy-to-Use, and Natural Guard Spinosad Landscape & Garden Insecticide.

Neem is not a “new” insecticide. The neem tree (Azadiracta indica) is native to India and South Asia and its insecticidal properties have been recognized for centuries. However, neem-based home garden pesticide products weren’t readily available on the garden store shelf until the last several years.

There are two types of pesticidal products derived from neem. Azadirachtin is made up of 25 closely related compounds extracted from the kernels of neem tree seeds. It acts as an insect growth regulator and disrupts the insect life cycle by inhibiting molting from one stage to the next as it matures. While it doesn’t kill adult insects, it can act as a deterrent to feeding and egg laying.

Neem oil is also made from neem seed kernels by a different extraction method and contains the oil fraction of the seed and doesn’t contain the azadirachtin compounds. It works much the same as other oils used to control pests on plants. It coats the insect’s body and causes suffocation. It also apparently has some fungicidal properties that prevent the germination and penetration of certain fungal spores that land on a leaf. Neem oil-based products help control aphids, whiteflies, scale crawlers, and spider mites. Regular repeat applications are needed for insect control as well as fungal control.

Azadirachtin-based products control lepidopterous caterpillars, leaf-feeding beetle larvae, sawflies, aphids, leafhoppers, plant bugs, grasshoppers, and some leaf miners. It has low mammalian toxicity and has low impact on most beneficial insect populations, but it is toxic to fish. Neem breaks down fairly rapidly once exposed to ultraviolet light and the environment. Repeated applications may be needed for problem infestations, keeping in mind that it’s primarily effective against immature insects and that death of treated insects is not immediate. Home garden products that contain azadirachtin and are cleared for use by Washington gardeners are Safer Bioneem and Bonide Grub Beater Insect Control.

Because there are so many newer, less familiar pest control products, it’s important to check out the labels of pesticide products and follow the directions for their safe and effective use. Today we learned about two types of products, some other time we’ll study some of the others.

Published: 5/3/2008 2:01 PM


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

This year many gardeners are facing the growing season with fear and trepidation. Diazinon, the old tried-and-true chemical that they used for many years to control insect pests is no longer available to gardeners. As an organophosphate insecticide, there were concerns about the health risks, especially to children, that diazinon posed. With the demise of this familiar chemical, gardeners are wondering what they can find to help them manage destructive pests in their garden.

One group of chemicals showing up in many home garden insect control products are the pyrethroids. These are man-made synthetic pesticides that are chemically similar to the natural pesticide pyrethrum. Pyrethrum is considered a natural chemical suitable for use by organic gardeners. It’s a natural chemical that comes from Dendranthemum cinerariaefolium, which is grown mostly in parts of Africa and Ecuador.

Pyrethrum is one of the most widely used organic pesticides. It’s valued for it’s quick knock-down effect on many insects. However, because this knockdown doesn’t always mean the insect is ‘down for the count,’ many of the pyrethrum products have a synergist (usually piperonyl butoxide known as PBO) added to them which magnifies the effect of the pyrethrum and leads to insect death.

Since pyrethrum has a very short residual, its use is primarily as a contact poison. This means the material must contact with the insect to be effective. It doesn’t kill via ingestion when the insects eat treated plant tissues. Because it has extremely short residual activity, many gardeners have not found pyrethrum to be a particularly effective tool in their attempts to manage garden pests.

Pyrethroids are synthetic chemicals that have been created to chemically imitate natural pyrethrum. The big difference between pyrethrum and pyrethroids is that these synthetic materials have been altered to provide better control of insects and longer residual activity.

While over 1000 of the pyrethroid synthetics have been created, only a handful are typically found in home and garden products. Resmethrin and allethrin have been available for a number of years and are typically found in short residual sprays for control of household pests, including wasps, hornets, flying insects, spiders, and mosquitoes. Permethrin can be found in sprays and granules sold for control of chewing and crawling insects.

The newest pyrethroids on the market are those with a longer residual and greater effectiveness in killing chewing and crawling insects. It is this group that is filling in part of the gap left by the withdrawal of diazinon. These newest pyrethroids include sfenvalerate, cyfluthrin, bifenthrin, deltamethrin, lambda-cyhalothrin, tralomethrin, cypermethrin, and others.

As with any pesticide product, you should always read and follow all the directions and precautions on the label. One thing to note is that some people using pyrethroids and pyrethrum containing products may have an allergic skin reaction to the materials. If you’re allergic to members of the chrysanthemum family, it’s probably best not to expose yourself to them via application of pyrethroid products. Another precaution that should be noted in our region is to avoid use of products containing the synergist PBO when the temperature is above 90 degrees, as plant damage can occur. The final precaution regarding their use is toxicity. While these products are not highly toxic to mammals, they are highly toxic to fish. Don’t spray them around bodies of water where fish reside.

Another type of chemical that will probably see increased use by gardeners are horticultural oils. The use of oil to control pests is not new. Different types of oils have been used for many years to control certain insect pests on plants. In recent history, horticultural oils were used primarily on dormant woody plants to control overwintering pests and were applied just before plants and insects started to grow in the spring. These oils were commonly called ‘dormant oils.’

A new ‘breed’ of horticultural oils are now being used for pest control both in the dormant season and also later in the season. These oils are highly refined petroleum oils which have had various chemical compounds and impurities removed. These ‘superior horticultural oils’ are now safe enough to use on many woody ornamentals and garden plants during the growing season.

Back in the ‘old’ days, the less highly refined horticultural oils used for pest control could only be applied to dormant woody plants to control overwintering pests, such as aphids and mites. The new horticultural oils can also be used on dormant plants in the same manner, but at a lighter rate they can be used on plants during the spring and summer.

Oils kill target insects by suffocation, the oils block their air holes (called spiracles) through which they breath. Scientists also believe they may also act as poisons that interfere with the insect’s normal metabolism or prevents its feeding. Oils are primarily useful against soft-bodied pests such as adelgids, aphids, eriophyid mites, spider mites, leafhoppers, scale insects, whiteflies, plant bugs, and even some caterpillars.

One concern about using oils on plants is the potential damage they can cause to plants if not used correctly. There is less hazard of injury to plants with the newest horticultural oils because they have been highly refined. These new oils can be used safely on a number of plants including many woody ornamentals, fruit trees, bedding plants, vegetables, and herbaceous plants. However, plant damage can occur if not used correctly.

Injury to plants can happen if too much oil is applied; if plants are under drought stress; if temperatures are above 90 degrees; if temperatures are below 45 degrees; if the relative humidity is over 90 per cent for 48 hours (not likely to happen here); if used too often; if the dormant rate is used on plants that are not fully dormant in the fall; and if used in combination with sulfur containing materials or applied soon after sulfur has been applied.

Certain plants are sensitive to oils and damage can occur, even if they are applied correctly. The pesticide label will indicate to which plants the oils should not be applied, but plants that are generally known to be sensitive include black walnut, hickory, cryptomeria, spruce, Douglas-fir, juniper, cedar, maple, redbud, and smoke tree.

Gardeners should not fear garden disaster without diazinon. As gardeners start to utilize these new substitutes, they should be able to effectively manage pests… as long as they understand the correct use of the materials and what types of pests they’ll control. Good luck!

Published: 5/14/2005 1:41 PM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

It’s that time of year again… time when owners of cherry, apple, crab apple, and pear trees need to be spraying their trees with pesticides to prevent wormy insects from destroying the fruit. This is especially important because area gardeners are neighbors to the commercial fruit industry. Unchecked pests in backyard trees, even single trees, are sources of infestation for nearby orchards. This causes problems for the commercial fruit grower and can lead to the greater use of pesticides to control pests or even a failure to keep the fruit pest-free and marketable.

Owners of backyard fruit trees and certain fruit-bearing ornamental trees should be “good neighbors” and make the effort to adequately control cherry fruit flies in cherries and codling moth in apples, crab apples, and pears. This is no easy task. It involves regularly spraying the entire crown of the trees with several pesticide applications or more during the growing season. It also requires the proper equipment for spraying and the application of the recommended chemicals at the right times. Quite simply, it’s a lot of work.

It is a lot of work and unsuspecting gardeners who planted fruit trees may find this task of pest control a burdensome task for which they don’t have the time… or the inclination. Unfortunately, they don’t have a choice. They are required by county law to control these tree fruit pests. So what options do you have if you have a fruit tree with wormy fruit, but don’t want to keep spraying it on a weekly basis?

Option One: The simplest solution is to remove the offending trees. Gardeners often have difficulty parting with a tree or any other plant from their yard or garden, but they should think of this as “tough love” for a tree that has become a delinquent.

Option Two: Gardeners who dream of picking fresh fruit from their own backyard trees, may want to consider planting fruit trees that don’t usually require regular spraying to control wormy pests in the fruit. This includes apricots, peaches, and plums. Plums are the most dependable and lowest maintenance tree fruit crop for would-be backyard orchardists. My favorite plums are ‘Autumn Sweet’ a newer large purple plum that bloom late, has firm sweet flesh, and dries well; ‘Shiro’ a round, yellow Japanese plum with sweet, juicy flesh; and ‘Elephant Heart’ a reddish-purple heart-shaped Japanese plum with tasty, sweet red flesh.

Option Three: It doesn’t seem to make much sense for gardeners to grow apples in our region where we can easily buy fresh fruit at packing houses, u-pick farms, or farmers’ markets. The supply of apples may be abundant and relatively inexpensive, but you can’t always find “your” favorite variety. I doubt I’ll ever find ‘Empire’ (my favorite) apples locally. You can grow your favorite “back-home” apple variety without sprays for codling moth using paper bags to protect the fruit.

At the same time you thin the fruit, you cover each one left on the tree with a special paper bag. That’s how they grow apples in Japan! A “Fruit Protection Bag” is a waxed paper bag with a double twist-tie that allows you to secure them over the developing apple. Raintree Nursery in Morton, Washington sells Fruit Protection Bags for apples and pears in groups of 100. Contact Raintree Nursery at 360-496-6400 or

What ever option you choose, be a good neighbor and keep the worms out of your backyard tree fruit. If you have fruit trees and need to know what sprays can be used to control codling moth in apples and pear and cherry fruit fly in cherries, contact the WSU Extension Office of Benton County at 735-3551 for a Home Orchard Pest Management Chart.

Published: 5/7/2007 4:09 PM


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

Over the last several years we’ve talked about some of the new, more environmentally friendly pesticides becoming available to home gardeners. These new products are helping replace pesticides that had been around for many years, such as diazinon, thiodan, and chlorpyrifos. Concerns about the health risk these older materials posed to humans, especially children, led to them being withdrawn from the home garden market.

Left without familiar pesticide products, the last few gardening seasons have been a challenge as gardeners tried to manage insect pests using newer and less familiar materials. Some of these products work quite well, but it’s important for gardeners to know how to use them effectively. With the growing season and the pest season at hand, now is the perfect time to review several of these new home garden pesticide products.

Spinosad: Here’s one new product that I predict will become a mainstay pesticide for gardeners. The spinosads are fermentation products of a soil bacterium. They have insecticidal and some even have miticidal properties. Insects are killed when they come in direct contact with the spinosad material or when they move onto treated surfaces. Insects are also killed by eating treated plant tissues. Spinosads work by exciting the insect’s nervous system, leading to muscle contractions, prostration with tremors, paralysis, and death.

Spinosad insecticide is most effective against a variety of different caterpillars, leaf beetle larvae, leaf miners, and some other pests too. Of particular interest to local gardeners is its control of thrips, Colorado potato beetle, corn earworm, codling moth, and cherry fruit fly. Unlike many of the other newer chemicals available to gardeners, it provides some residual control.

Common home garden products on the market containing spinosads are Monterey Garden Insect Spray (Monterey Lawn & Garden), Bull’s-Eye Bioinsecticide (Gardens Alive), Green Light Lawn & Garden Spray Spinosad (Green Light), and Ferti-Lome Borer, Bagworm, Leafminer, & Tent Caterpillar Spray.

Imidacloprid: Imidacloprid is the oldest member of a major new chemical family of insecticides called neonicotinoids. They work by interfering with the transmission of impulses in the insect nervous system. When exposed to imidacloprid, insects stop feeding soon after treatment and typically die within one to two days. It’s relatively fast action and long residual activities are highly desirable characteristics. However, its systemic properties are what make it particularly useful and effective.

While some formulations of imidacloprid are applied as foliar sprays, gardeners find the formulations that are applied as a root drench very useful. All a gardener needs to do is mix it with water and then apply it to the soil for uptake by the roots. This avoids the difficulty of spraying tall plants or spraying under windy conditions. Applied as a drench and taken up by the roots, it provides good control of many sucking insects, including aphids, adelgids, thrips, lacebugs, some scales, bugs, pyllids, and mealy bugs. It’s also effective against certain leaf beetles and leaf-miners.

One drawback in using imidacloprid is that when applied to the soil for uptake by the roots, it may take several weeks to several months to be fully absorbed and moved throughout the plant, especially in large trees. However, once distributed throughout the tree, it’s effective for six months or more. The other drawback for gardeners is that it’s only labeled for use on ornamental plants and trees, not on vegetables or tree fruit.

Common home garden products containing imidacloprid are packaged by only one company, Bayer Advanced. Their Tree & Shrub Insect Control Concentrate (drench), Rose & Flower Insect Killer Concentrate (spray), and All-in-One Rose & Flower Care (drench with a systemic fungicide) all contain imidacloprid.

Esfenvalerate: Esfenvalerate is one of the many pyrethroids used for insect pest control. Pyrethroids are synthetic pyrethrin. (Pyrethrin is a naturally occurring plant derived insecticide.) The newer pyrethroids like esfenvalerate have been designed to be longer lasting than the earlier pyrethroids. Like many other insecticides, pyrethroids kill by overexciting the insect’s nervous system. Esfenvalerate provides a quick knock-down of many sucking and chewing insect pests and it has some residual control.

Several products containing esfenvalerate are labeled for use on garden vegetable crops as well as ornamentals and one is also labeled for use on fruit. These esfenvalerate containing products are Bug Buster (Monterey Lawn & Garden Products), Ortho Bug-B-Gon Garden & Landscape Insect Killer Concentrate (Ortho), and Ortho Bug-B-Gon Max Garden & Landscape Insect Killer RTU (Ortho).

Cyfluthrin: Is another synthetic pyrethroid that works on contact and as a stomach poison. It’s used to control a variety of sucking, flying, and chewing insects. It can be found in two Bayer Advanced products, Rose & Flower Insect Killer and Power Force Multi-Insect Killer.

When using the newer insecticide products (or older familiar ones), it’s always best to read the label before mixing and applying. While these new products may be safer for us to use, they can still cause problems when used improperly. Some are highly toxic to bees, fish or other wildlife. Read the label thoroughly and follow all the precautions.

Published: 3/18/2006 11:26 AM

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