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
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Modes of actionPreventative*FeedingEgg layingSpore and seed germination
CurativeSuffocationStarvationDisruption of biochemical and/or physiological processes
*must be able to predict
Dr. Linda Chalker-Scott WSU Extension Urban
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
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Curative - suffocationHorticultural oilsKaolin – fine particle clayDiatomaceous earth – fine particle
silica
Dr. Linda Chalker-Scott WSU Extension Urban
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
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Horticultural oils
Curative - starvationStomach poison
Bacillus thuringiensis (Bt)PyrethrinsSpinosad
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Ingestible insecticides
Dr. Linda Chalker-Scott WSU Extension Urban
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
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Pesticide realitiesPesticide registration does not include product efficacy testingSuccess in lab testing does not guarantee success in the field
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Maize gluten mealHigh nitrogen by-product of corn millingRegistered herbicidefor turf
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
MGM effectiveness on crab grass control
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
MGM impact on crab grass root growth
FungicidesBacillus subtilus Canola, corn, jojoba and sesame oilsCopper octanoate Garlic oilKaolinPotassium bicarbonateSulfur
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
HerbicidesCinnamon and lemongrass oils Clove and eucalyptus oilsHerbicidal soap LimoneneMaize gluten meal Soybean oilVinegar (20% acetic acid)
Dr. Linda Chalker-Scott WSU Extension Urban
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
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Volatile oils (fragrant)Work best in enclosed areasCan be phytotoxic
Essential oils for homeowner use
Dr. Linda Chalker-Scott WSU Extension Urban
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.”
Dr. Linda Chalker-Scott WSU Extension Urban
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
Dr. Linda Chalker-Scott WSU Extension Urban
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
Dr. Linda Chalker-Scott WSU Extension Urban
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
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Phytotoxic oils
Dr. Linda Chalker-Scott WSU Extension Urban
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
Dr. Linda Chalker-Scott WSU Extension Urban
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
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
Dr. Linda Chalker-Scott WSU Extension Urban Horticulturist
Online information
Dr. Linda Chalker-Scott WSU Extension Urban Horticulturist
Go back to college with the Garden Professors
http://blogs.extension.org/gardenprofessors/
Dr. Linda Chalker-Scott WSU Extension Urban Horticulturist
BertHolly Jeff
Linda
Dr. Linda Chalker-Scott WSU Extension Urban Horticulturist
Visit us on Facebook!www.facebook.com/TheGardenProfessors
Dr. Linda Chalker-Scott WSU Extension Urban Horticulturist
Visit us on Facebook!https://www.facebook.com/groups/
20037544148
Dr. Linda Chalker-Scott WSU Extension Urban Horticulturist
New WSU website for garden infohttp://gardening.wsu.edu/
Dr. Linda Chalker-Scott WSU Extension Urban
Horticulturist
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