The Natural Lawn & Garden

Healthy Landscapes for a Healthy Environment

Control

NaturalPest, Weed & Disease

Preliminary

Follow these Basic

Steps to Natural

Pest, Weed and

disease Control

❖ Create a healthy garden tostop pest problems before theystart. Healthy plants and soilnot only resist pests anddiseases, they also encouragebeneficial garden life.

❖ Identify pests before you spray,stomp or squash. When yousee damaged plants or whatappear to be pests, use theNatural Pest Control Resourceson page 10 and 11 to identifythe “suspects” first. What youthink is a pest may actually be abeneficial insect!

❖ Give nature a chance to work.Do not try to eliminate pests atthe first sign of damage.Garden pests feed beneficialinsect populations and allowthem to grow.

❖ Use the least toxic pestcontrols available. You canoften control pests by usingtraps or barriers, or by simplyremoving large pests andinfested plant parts. Thesemethods do not harmbeneficial garden life or theenvironment. If pesticides arethe only way to control aproblem, look for the leasttoxic ones and closely followthe application tips outlined onpages 6 and 7.

Why Manage Your Garden Naturally?

Insects, spiders, and other crawling or flying creatures are a vital part of healthy gardens. Mostperform important jobs like pollinating flowers, recycling nutrients and eating pests. In fact, lessthan 1% of garden insects actually damage plants. Unfortunately, the pesticides often used tocontrol pests and weeds are also toxic to beneficial garden life — and may harm people, pets, salmonand other wildlife as well.

Start with Prevention

❖ Build healthy soil to grow healthy plants. Amend and mulch entiregrowing beds with compost, and fertilize moderately with naturalorganic or slow-release fertilizers to grow vigorous, pest-resistantplants. See the Growing Healthy Soil guide* for more details.

❖ Plant right. Place each plant in the sun and soil conditions it prefers.Select varieties that are known to grow well in your garden conditionsand resist common pest and disease problems. See the Choosing theRight Plants guide* for help selecting plants ideal for each spot in yourgarden.

❖ Give your plants some space. Good air circulation can prevent orreduce many disease and pest problems. Space plants so they haveplenty of room to grow, and remove some when they become toocrowded.

❖ Water wisely. Overwatering and underwatering are two of the mostcommon causes of plant problems. Observe plants and check soil asdeep as roots grow before and after watering to make sure plants getwhat they need, but not too much. Water early in the day or usesoaker hoses to prevent diseasescaused by wet leaves. For moredetails, see the Smart Wateringguide.*

❖ Clean up. Remove weeds, woodboards and other yard debristhat can harbor pests anddisease. Fallen leaves and fruitfrom plants like apple trees androses with persistent diseasessuch as scab, rust and mildewshould be put in curbside yardwaste collection containers—notin home compost piles, ravines,streams or lakes.

❖ Diversify and rotate annualcrops. Grow a variety of plantsto prevent problems fromspreading, as well as to attractpest-eating insects and birds.Do not plant the same type ofannual vegetables in the samespot each year; crop rotationprevents pests and diseases frombuilding up in the soil.

Bad bug: Aphids

Good bug:Lady beetle larva

When is it a pest?

❖ Pest refers to an insect,animal, plant or micro-organism that causesproblems in the garden.

❖ Beneficials are organ-isms in the air, on theground or in the soilthat do good thingsfor your garden, likepollinating flowers,feeding on insect pests,or improving soil.

❖ Some pests are alsobeneficials.For example, yellowjackets are both preda-tors of pests and painfulto humans. Whenconsidering anycontrols, weigh acreature’s damageagainst damage to theentire community ofgarden life.

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Copper slug barrier

Protecting a crop with afloating row cover

Washing aphids from underside of leaf

1What to Do If a Pest Problem Develops

Use Physical Controls FirstMany pests can be kept away from plants with barriers or traps, orcontrolled by simply removing infested plant parts. These controlsgenerally have no adverse impact on beneficial garden life, people or theenvironment.

RemovalPests and diseased plant parts can be picked, washed or vacuumed offplants to control infestations. In fact, pulling weeds is a natural pestcontrol!

Handpicking can be effective for large pests like cabbage loopers,tomato hornworms, slugs and snails.

Pruning out infestations of tent caterpillars is effective on a smallscale. Control leaf miners on beets or chard by picking infectedleaves. Put infestations in the garbage or curbside yard wastecollection containers — not in home compost piles, which do notget hot enough to destroy pests.

Washing aphids off plants with a strong spray of water from a hosecan reduce damage. Repeated washings may be required, as thisprocess does not kill the aphids.

TrapsIt is possible to trap enough pests like moths and slugs to keep themunder control. You can also use traps for monitoring pest numbers todetermine when controls may be necessary. Two simple and effectivepest traps include:

Cardboard or burlap wrapped around apple tree trunks in summerand fall will fool coddling moth larvae into thinking that they havefound a safe place to spin their cocoons as they crawl down the treeto pupate. Traps can be peeled away periodically to remove cocoons.

Slug traps drown slugs in beer or in a mixture of yeast and water.

BarriersIt is often practical to physically keep pests away from plants. Barriersrange from 2-inch cardboard “collars” around plants for keeping cut-worms away to 8-foot fences for excluding deer.

Floating row covers are lightweight fabrics that let light, air andwater reach plants, while keeping pests away — they are useful forpests like rust flies on carrots, leaf miners on spinach, and rootmaggots on cabbage, broccoli and cauliflower.

Mesh netting keeps birds away from berries and small fruit trees.

A band of sticky material around tree trunks stops ants fromclimbing trees and introducing disease-carrying aphids.

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Centipedes may look scary, but they feedon slugs and a variety of small insect pests.

RepellentsA variety of homemade andcommercial preparations can beused to keep pests away fromplants. Many gardeners claimrepellents work, although someare not consistently effective inscientific trials.

A mixture of raw eggsblended with waterproduces a taste and odorthat offend deer; somegardeners add garlic and hotpepper. Spraying this mixonto plant foliage can repeldeer for several weeks, oruntil it is washed off by rainor sprinklers.

Garlic oil and extracts areused to repel a variety ofinsect pests, and also workas fungicides.

Meet TheBeneficials!Spraying anypesticide may killmore beneficials thanpests. Think twicebefore you spray.

Ladybugs and their less attractivelarvae devour aphids, mites, scalesand other pests.

Ground beetles eat slugeggs and babies, plusother soil-dwelling pests.

Lacewings and their alligator-like larvaeeat aphids, scales, mites, caterpillars andother pests.

Hornets and yellow jackets areeffective predators. However, controlsmay be necessary if they pose a threatto people or pets.

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Lady beetle larvae and adults feed onsoft-bodied insects such as aphids,mealybugs, scale insects, and spidermites as well as insect eggs.

Soaps, Oils and Mineralsv Horticultural oils smother

mites, aphids and their eggs,scales, leaf miners, mealybugsand many other pests; they havelittle effect on most beneficialinsects.

v Horticultural soaps dry outaphids, white flies, earwigs andother soft-bodied insects. Theymust be sprayed directly ontothe pests to work, so repeatedapplications may be necessary.There are also soap-basedfungicides and herbicides.

v Sulfur controls many fungaldiseases such as scab, rust, leafcurl and powdery mildewwithout harming most animalsand beneficials. For greatereffectiveness, sulfur can bemixed with lime. Sulfur is alsofrequently combined with othermaterials to create more toxicfungicides.

v Baking soda (1 teaspoon) mixedwith dishwashing liquid (a fewdrops) and water (1 quart) hasbeen used by rose growers toprevent mildew. A commercialproduct is also available thatcontains potassium bicarbonate,which is similar to baking soda.

v Iron phosphate slug baits areless toxic than other slug baitsand not as hazardous to dogs.

Biocontrolsv Bacillus thuringiensis (Bt) is

a common, commerciallyavailable bacterium that poisonscaterpillar pests, includingcutworms, armyworms, tentcaterpillars, cabbage loopers,and corn earworms. Bt is nottoxic to people, animals, fish orinsects — although it can killcaterpillars of non-pestbutterflies and moths.

v Predatory nematodes kill awide variety of pests, includingcutworms, armyworms, rootmaggots, crane fly larvae, rootweevil larvae and other soil-dwelling pests. Proper soiltemperature and moisture arerequired for nematodes to beeffective.

v Beauveria bassiana is a com-mercially available fungus thatdestroys an extensive range ofpest insects.

v Beneficial insects like ladybugsand lacewings can be purchasedand released. A healthy anddiverse garden will usually havelots of them around already.

v Compost teas use compostorganisms to help control leafand root diseases. They aresometimes effective, and theywon’t harm any beneficialorganisms. Call the NaturalLawn & Garden Hotline at(206) 633-0224 for moreinformation on using compostteas and other biocontrols.

BotanicalsThese plant-derived insecticidesdegrade quickly in the sun orsoil. However, most are initiallytoxic to people, animals, fishand beneficial garden life.Use cautiously and follow labeldirections closely, just as whenapplying synthetic pesticides.v Neem oil kills and disrupts

feeding and mating ofmany insects, includingsome beneficials. Also aneffective fungicide, neemoil is the botanical that isleast toxic to people,animals, birdsand fish.

v Pyrethrum, ryania andsabadilla kill many toughpests, but are also quitetoxic to beneficial insects,people, fish and otheranimals. These pesticidesshould only be used as a lastresort.

2Use Least-Toxic Pesticides When Physical Controls

Don’t Work

The pesticides listed below have a low toxicity or break down quickly into safe byproducts whenexposed to sunlight or the soil are the least likely to have adverse effects. However, even these pesticidescan be toxic to beneficial garden life, people, pets and other animals — especially fish. They should beused carefully and kept out of streams, lakes and Puget Sound. Refer to Resources on page 10.

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Use Synthetic Pesticides Only As a Last Resort

When physical and least-toxic controls fail to control a pest, other pesticides maybe used as a final resort. But first, consider your pest problem. Is it the result ofpoor plant placement? Is it likely to recur after pesticide treatment? Keep inmind that scientists have found 23 pesticides — including four commonly usedinsecticides — in local streams, some at high enough levels to harm fish and whatthey eat.

v Don’t use services that spray insecticides or herbicides on a prescheduledplan. Preventive sprays can disrupt natural controls, and may do more harmthan good. Fungicides are an exception because they only work when appliedprior to the appearance of the problem — use the least toxic fungicides, onlyon plants which have been infected in previous years.

v Look for the least toxic pesticide. Ask nursery staff for help identifying theleast toxic pesticides for your pest problem. Or call the Natural Lawn andGarden Hotline at (206) 633-0224 and ask for Grow Smart, Grow Safe — AConsumer Guide to Lawn and Garden Products. Avoid products with warningslike “highly toxic,” “causes permanent eye damage,” or “may be fatal ifswallowed.” Choose “ready-to-use” products, which are safer to use instead ofmore toxic concentrates which require mixing.

v Don’t use broad-spectrum insecticides like diazinon, chlorpyrifos(Dursban), malathion and carbaryl. These are likely to kill more of thenatural enemies than the pests. Pest populations may soar and become moreof a problem than before they were sprayed.

v Avoid “weed and feed” and other pesticides that are broadcast over theentire yard. Instead, spot apply the least toxic product, only where you havea pest or weed.

v Buy only as much as you need. Unused pesticides are dangerous to store ordispose, and expensive for local governments to dispose of.

v Read and follow label directions carefully. Only use pesticides on theplants and pests listed on the label, and apply exactly according to labeldirections. Be sure to wear specified protective clothing andequipment, and keep children and pets off application areas forthe specified period of time on the label.

v Apply only when and where pests are present. Timing is critical with all pest control. Most pesticides should not be used as a preventative,except fungicidal tree sprays.

v Dispose of unused pesticides and containers properly. Emptycontainers should be disposed of in your garbage. Dispose of unusedpesticides at household hazardous waste disposal sites; see theResources List on page 11 for more information.

What About Weeds?

A “weed” is simply a plant in the wrong place. Some weeds competewith desirable plants, but many are merely aesthetic concerns. Forinstance, white clover is often considered a weed in lawns, yet it staysgreen when dry conditions turn lawns brown, and its roots supportbacteria that transform nitrogen from the air into plant fertilizer. Soclover feeds your lawn every time you mow!

vvvvv Accept a few weeds in your lawn. Target the problem weeds, andleave the others. Many people who see a lawn with 10-20 percentweed cover consider it healthy and good looking. For tips onmaintaining a dense, healthy lawn that crowds out weeds, refer tothe Natural Lawn Care guide.*

vvvvv Prevention: don’t give weeds a chance. Weeds thrive in bare soiland neglected garden areas. Plant spreading ground cover tooutcompete weeds, or smother them with weed barriers and lotsof mulch. See the Growing Healthy Soils guide* for more information on mulches.

vvvvv Physical control: be a control freak with problem weeds. Asingle weed flower can produce thousands of seeds. To preventfuture infestations, remove weeds before they go to seed.Cultivating with a hoe works well on young or shallow-rootedweeds in garden beds or paths. Long-handled pincer-type weed

Have you seen these“noxious” weeds?

There are a few non-native “nox-ious weeds” that property ownersare required to control byWashington State law to preventtheir spread. Check the State’snoxious weed website for a list, atwww.wa.gov/agr/weedboard

Using a weed pullerTorches work on weeds in cracks or gravel

Giant Hogweed

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Spot apply the least toxic herbicide

pullers work great for weeds with taproots like dandelion and thistle, espe-cially in lawns when soil is moist. Propane weeding torches scorch and killmost weeds without damaging plants around them; repeated flametreatment may be needed for tough weeds. Be aware of fire hazards whenusing torches, as well as the potential to burn your feet. Spring and fall,when the ground is moist and weeds have just sprouted, is the safest andmost effective time to use a torch.

vvvvv Least toxic controls: corn, soap or vinegar? Herbicides with low toxicityto beneficial garden life, people and wildlife include corn gluten — amilling byproduct which is used as animal feed — herbicidal soaps, andvinegar (acetic acid). Corn gluten prevents the growth of weed seedlings,but actually fertilizes established plants. It is sold under several brandnames. Corn gluten’s effect is short-lived, so applications must be timedto coincide with seed germination. Herbicidal soaps and vinegar bothdamage leaf cells and dry out plants. Tough weeds resist these herbicidesor resprout from roots. Some concentrated vinegar products can causepermanent damage if accidentally splashed into the eyes. Ready-to-usedilutions are safer.

vvvvv The last resort: spot apply synthetic herbicides. When extreme weedproblems call for treatment with synthetic chemical herbicides, carefullyapply them (only as directed on the label) directly onto weed leaves. Donot use “weed and feed” or pre-emergent products, which spread toxicherbicides all over lawns or gardens and are likely to run off into streamsand Puget Sound. If you are applyingan herbicide on a regular basis, there isprobably a landscape design or soilproblem that needs to be addressed.

Spreading mulch to prevent weeds

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Natural Pest Control Resources

Call the Natural Lawn and Garden Hotline at (206) 633-0224 to ask a question, or torequest other guides including Natural Lawn Care; Growing Healthy Soil; Choosing the RightPlants; Smart Watering; Composting at Home; Natural Pest, Weed & Disease Control; GrowSmart, Grow Safe; How to Choose a Landscape Company; Good Bugs, Bad Bugs; and a brochureon crane flies. Landscape professionals can request the series of Pro-IPM professionalfactsheets, or the report Ecologically Sound Lawn Care. Community groups, garden clubs, andlandscape professionals can also request a Green Gardening program presentation to learnmore about natural pest management methods. You can also visit www.savingwater.org toview many of these publications online. View the Pro-IPM series of factsheets atwww.cityofseattle.net/util/proipm

Books For Gardenersv Sunset Western Garden Problem Solver. Photos and descriptions of many common pest,

disease and weed problems, plus less-toxic ways to prevent and manage them.

v Rodale’s Color Guide of Garden Insects. Photos for identifying pests and beneficialinsects, with recommended organic controls for many pests.

v Rodale Pest and Disease Problem Solver. Photos and descriptions of many common pestand disease problems, plus less-toxic ways to prevent and manage them.

v Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide bySteven Dreistadt. Detailed descriptions of pests by plant type, as well as pest life cyclesand controls.

v Pests of the Garden and Small Farm: A Grower’s Guide to Using Less Pesticide by MaryFlint. Detailed descriptions of pests by plant type, plus pest life cycles, and controls.

v Common Sense Pest Control by Olkowski, Daar & Olkowski. Least-toxic solutions forhome, garden, pets, and community.

WSU-King County Cooperative Extension Resourcesand Servicesv Master Gardener Clinics. Master Gardener volunteers are available to answer

questions and diagnose problems over the phone, or at clinics held regularlyaround the county. For phone help and clinic locations, call (206) 296-3440between 10 A.M. and 4 P.M., Monday through Friday.

v www.metrokc.gov/wsu-ce/ (click on Gardening). View Cooperative Extensionpublications on horticulture and pest management online, or link to Extensionand Master Gardener programs in counties around Washington.

v Dial Extension. Select and listen to tapes on many gardening topics,24 hours a day, at (206) 296-3425.

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v Publications. Order many bulletins on growing plants and managingpests for a small charge at (800) 723-1763. Several authoritative bookscan also be ordered, including Landscape Plant Problems: A PictorialDiagnostic Manual, and Pacific NW Integrated Pest Management Manual.Three books primarily for professionals, excellent for diagnosing plantproblems by symptom, are PNW Insect Management Handbook, PNWPlant Disease Management Handbook, and PNW Weed ManagementHandbook (focus is on chemical controls).

Other Resourcesv Landscape Professionals. Many landscape and nursery professionals are

skilled in environmentally friendly landscaping. Find them atwww.savingwater.org/landscape.htm by scrolling down to LandscapeIndustry Contacts, or call (206) 633-0224 and ask for the brochure Howto Choose a Landscape Company.

v Seattle Tilth. To learn more about organic gardening classes, getdirections to demonstration gardens, or to purchase the Maritime NWGardening Guide, call (206) 633-0451.

v Washington Toxics Coalition. To purchase publications on non-toxicpest management strategies and products, call (206) 632-1545 or (800)844-SAFE or go to www.watoxics.org

v Local Hazardous Waste Management Program website. To learn moreabout safer gardening and pest control, go towww.metrokc.gov/hazwaste/house/pests.html

v University of California IPM. For pest descriptions, photos andmanagement options for home gardeners and landscape professionals,go to http://axp.ipm.ucdavis.edu

Pesticide Disposal and Emergencies

v Poison Control. In case of pesticide poisoning, call (800) 222-1222,or just call 911.

v Washington State Department of Agriculture. If you have a concernabout a pesticide application or want to report a violation, call WSDA at(360) 902-2040.

v Household Hazards Line. For information on pesticide disposal,including the days, hours and locations of disposal facilities, call theHazards Line at (206) 296-4692 or (800) ToxicEd.

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* Refer to the back of this guide for a list of all of the freeNatural Lawn & Garden guides and to find out how to obtain them.

Photographs by Joanne Jewell and Carl WoestwinIllustrations by Wilda Boyd

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The Natural Lawn & Garden Series:● Natural Lawn Care● Growing Healthy Soil● Smart Watering● Choosing the Right Plants● Natural Pest, Weed & Disease Control● Composting at Home

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