city of seattle organic pesticides

Dr. Linda Chalker-Scott WSU Extension Urban

Horticulturist

Organic PesticidesWhat works, what doesn’t, and

why

Seminar recommendations

Based on current, peer-reviewed scienceInclude materials certified as OMRIInclude materials registered *only* for home garden use in Washington state


Horticulturist

Modes of actionPreventative*FeedingEgg layingSpore and seed germination

CurativeSuffocationStarvationDisruption of biochemical and/or physiological processes

*must be able to predict


Horticulturist

Preventative - feeding Odor

Essential oilsNeem

Taste Garlic (lectin)NeemPyrethrin

Touch Horticultural

oils

KaolinDr. Linda Chalker-Scott WSU Extension Urban

Horticulturist

Preventative – egg laying & germination

Prevent insect egg layingHorticultural oilsKaolin

Prevent fungal spore germinationBacillus subtilisHorticultural oilsKaolinPotassium bicarbonateSulfur


Horticulturist

Curative - suffocationHorticultural oilsKaolin – fine particle clayDiatomaceous earth – fine particle

silica


Horticulturist

Includes those made from plants (seeds, leaves, bark) and petroleumMost effective on soft bodied insectsMay suppress diseaseMust apply before symptoms appearCan be phytotoxic Can injure beneficials


Horticulturist

Horticultural oils

Curative - starvationStomach poison

Bacillus thuringiensis (Bt)PyrethrinsSpinosad


Horticulturist

Ingestible insecticides


Horticulturist

Includes Bt, neem, pyrethrins and spinosadMore targeted to pest species

Curative - disruptionWeed/weed seedling deathMaize gluten meal, vinegar

Insect cuticle abrasionDiatomaceous earth, kaolin, potassium laurate (soap)

Insect growth and development interference

Neem, nematodes (microscopic worms)

Insect enzyme poisoningCopper octanoate

Insect neurotoxinPyrethrins, spinosad


Horticulturist

Pesticide realitiesPesticide registration does not include product efficacy testingSuccess in lab testing does not guarantee success in the field


Horticulturist


Horticulturist

Maize gluten mealHigh nitrogen by-product of corn millingRegistered herbicidefor turf


Horticulturist

MGM effectiveness on crab grass control


Horticulturist

MGM impact on crab grass root growth

FungicidesBacillus subtilus Canola, corn, jojoba and sesame oilsCopper octanoate Garlic oilKaolinPotassium bicarbonateSulfur


Horticulturist

HerbicidesCinnamon and lemongrass oils Clove and eucalyptus oilsHerbicidal soap LimoneneMaize gluten meal Soybean oilVinegar (20% acetic acid)


Horticulturist

InsecticidesBt, nematodes and spinosadCanola, cottonseed, mineral and sesame oilsClove and mint oilsDiatomaceous earth and kaolinGarlic oilNeem Nematodes Potassium lauratePyrethrins Dr. Linda Chalker-Scott

WSU Extension Urban Horticulturist

Essential oils


Horticulturist

Volatile oils (fragrant)Work best in enclosed areasCan be phytotoxic

Essential oils for homeowner use


Horticulturist

Insects/microbes:cinnamon, clove, rosemary and thyme mixtureInsects/microbes: neem oilAnts: clove oil, mint oilRoaches: mint oilDeer: black pepper oil, garlic oil

Popular mixed essential oil products

“…blending extracts…does not ensure enhanced biological activity.”“…numerous plant-derived essential oil products…have not been subject to rigorous evaluation.”“Products vary in their effectiveness against certainarthropod pests…and are phytotoxic.”


Horticulturist

Pesticide realitiesAll registered pesticides are tested to determine toxic effects on people and on ecosystemsHome remedies and other unregistered pesticides can be harmful to people, pets and the environment


Horticulturist

Potential drawbacks – big and small

Natural does not equal “safe”Lead arsenate used as a pesticide until 1988Nicotine and rotenone used as insecticides until about 8 years ago


Horticulturist

Potential drawbacks – big and small

Broad spectrum pesticides can kill beneficials, other non-target organismsMore frequent application is often necessary with organic pesticidesSome products phytotoxic


Horticulturist

Phytotoxic oils


Horticulturist

Species-specific Too much appliedTemperature too highTest first!

Potential drawbacks –

big and smallAny improperly used pesticide can contaminate the environmentAny improperly used pesticide can create resistant pest populations


Horticulturist

DDT resistant insects

Roundup resistant

weeds

Dr. Linda Chalker-Scott WSU Extension Urban Horticulturist

PICOL databasehttp://cru66.cahe.wsu.edu/labels/Labels.php

Tips for creating naturally healthy gardens and

landscapesPurchase disease-resistant plantsSelect plants adapted to your site conditionsKeep plants happy – healthy plants are more resistant to pests and disease Increase your plant palette – a more biodiverse garden is more resistant to pests and diseaseMaintain good garden hygiene by removing infected plant tissues


Horticulturist


Online information


Go back to college with the Garden Professors

http://blogs.extension.org/gardenprofessors/


BertHolly Jeff

Linda


Visit us on Facebook!www.facebook.com/TheGardenProfessors


Visit us on Facebook!https://www.facebook.com/groups/

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New WSU website for garden infohttp://gardening.wsu.edu/


Horticulturist

city of seattle organic pesticides

Education