This document provides information on alternatives to pesticides for home gardeners. It discusses using integrated pest management principles, including cultural, physical, biological and chemical controls. Specifically, it details over 100 plant diseases, insects, mites, nematodes and weeds currently controlled by pesticides. It then outlines cultural, physical and biological control strategies and techniques gardeners can use to manage pests without chemicals, including plant selection, sanitation, handpicking, water sprays and beneficial insects. The document concludes with a brief discussion of chemical controls and minimizing their negative effects.

1. 2/15/2009
Number of Species Currently
Controlled with Pesticides
Diseases 137
Home Garden Seminar
Josephine County Master Gardeners Insects 304
Mites 34
Alternatives to Pesticides Nematodes 23
Gail Langellotto
Urban and Community Horticulture Specialist
Weeds 102
OSU Extension and Department of Horticulture
Agricultural Effects upon
Conservation Biological Control
Diversity Equilibrium
40
• Few studies have been conducted in garden
30
systems
20
– Exception: Shrewsbury and Raupp (2006). Do top-down
versity
10
or bottom up forces determine Stephanities pyriodes in
0 urban landscapes?
p
Div
-10 Two Dimensional System Three Dimensional System
-20
-30
-40
Pristine Conventional Alternative
"Natural" Agriculture Agriculture
Components
Landscape
Natural Disease
Ecology Pest
Enemies Complex
Complex
• Raupp et al. 2001. Plant species diversity
and abundance affects the number of
Management
arthropod pests in residential landscapes.
Land Plant Abiotic
Land
Diversity Factors
Soil Soil
Nutrients Organic
Nematodes
Matter
Micro/
Macro Microbial
Inverte- Flora
brates
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2. 2/15/2009
Climbing the Alternatives Ladder Principles of IPM
Regional Integration
• Prevent Problems
Level III
Systems Integration
• Monitor the plants
Level II
• Identify the pest organism
y p g
Multi-species / Multi-tactic
Multi- Multi- • Establish an acceptable injury
Level I
Integrated Strategies
threshold
• Manage using all available
Multiple Tactics
strategies
Pesticides
Objectives Manage Using All Available Strategies
• Provide a basic understanding of how to
use IPM Principles to reduce pesticide use Cultural Least Toxic
in the home and garden. Physical
Biological
• Reduce pesticide use by managing using Chemical Most Toxic
all available strategies
– Cultural
– Use a least hazardous approach, that will
– Physical also enact effective control
– Biological
– Chemical
Cultural Control  Prevention! Plant Selection: Resistant Plants
R. davidsonianum Adult Root Weevil
Damage to Leaves
• Altering your garden or gardening practices
to reduce pest populations or injury
• Reduce plant stress through proper
Root Weevils
horticultural practice
• Three Components
– Plant Selection
– Plant Installation
List of Rhododendrons Resistant to Root Weevils can be found at:
– Plant Maintenance http://www.co.thurston.wa.us/health/ehcsg/pdf/weevil%20guide.pdf
Resistant varieties
Information on Managing Root Weevils in the Pacific Northwest:
http://extension.oregonstate.edu/catalog/pdf/ec/ec1485.pdf
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3. 2/15/2009
Plant Selection: Companion planting Plant Installation
• Pests and the Plants that Repel Them • Improper planting often results in stressed
Flea beetle Catnip, marigold, nasturtium, peppermint, rue, spearmint, plants.
southernwood, tansy
• Compacted soils are often a particular
Japanese beetle Catnip, chives, garlic, nasturtium, odorless marigold, tansy,
white geranium problem on home sites.
Rabbit Garlic, marigold, onion
Slugs and Snails Fennel, garlic, rosemary
Spider mite Coriander, dill
http://counties.cce.cornell.edu/Chemung/publications/companion-planting.pdf
Planting container plants Root Preparation Prior to Planting
• Thoroughly preparing
• Container plants with the roots prior to
circling roots or that planting on root-
are root-bound should bound pots usually
have these problems improves growth
corrected prior to immediately as well
planting. as plant survival
Planting container plants Cultural Control: Plant Maintenance
• Size of planting hole • Water for deep, spread roots
• Depth of planting • Fertilizing
• Finish by watering the – Too much fertilizer can increase insect pest
plant in well problems as much as too little fertilizer.
• Time of planting • Mulching / Groundcovers
– Can reduce weed problems
– Avoid bringing new weeds to the garden in
manure, straw
• Remove and properly dispose of garden
debris
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4. 2/15/2009
Disease Management: Sanitation Physical/Mechanical Control
• Clean up Debris • Use of physical barriers, machines or
objects to prevent an infestation
(preventative), or kill the pest (remedial)
– Horticultural fabrics to cover plants
(preventative)
– Flyswatter (remedial)
Physical Control of Weeds Weed Management
• A sharp hoe and lots o’ diligence • Weeds are easier to kill when they are very
• Mulch! small – “white thread” to 2-3 true leaves.
• Cover crops • Mechanical weeding is more effective during
warm, dry, windy weather. Plants can re-root in
• Crop rotation cool wet weather.
et eather
• Whenever possible prevent weeds from • In the Vegetable Garden or Home Orchard-
going to seed – Control weeds early in crop growth
– Cover crops can reduce subsequent weed pressure
Weed Management Physical Control: Sticky barrier
• Weeds are easier to kill when they are very • Can prevent
small – “white thread” to 2-3 true leaves. pests from
• Mechanical weeding is more effective during climbing and
warm, dry, windy weather. Plants can re-root in colonizing tree.
cool wet weather.
et eather • Can prevent
• Control weeds early in crop growth pests from
• Cover crops can reduce subsequent weed climbing down
pressure tree to pupate
in soil
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5. 2/15/2009
Physical Control: Collars and
Copper Barriers for Molluscs Cages
Plant Cage on Radishes
Cabbage Maggot Control
Brown Garden Snail
Tin Collar
Cutworm Control
Physical Control: Row Covers Handpicking
• Covers many plants,
or entire rows
• Protection for
seedlings, or during
other vulnerable times
lnerable
• Light, thermal and air
environment will be
modified
Place insects in soapy
water to kill them
Water Sprays Pruning
Spider
Mites
Spray plants with water to
dislodge aphids.
Aphids
p
Aphids
Spider mites
Must be sprayed regularly
to prevent recolonization.
Tent caterpillars
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6. 2/15/2009
Vacuuming Tilling
Boxelder Bug Flea
Garden symphylan
Asian Ladybug Beetle
Tilling
Physical Control: Bug Zappers Biological Control
• Biological control is the use of living organisms
—parasites, predators, or pathogens—to
maintain pest populations below economically
damaging levels, and may be either natural
(conservation) or applied (augmentative).
(augmentative)
Royal Walnut Moth The 3 P’s:
sitting on a bug zapper Predators, Parasitoids, Pathogens
Beneficial Aspects of Arthropods
• Pollinators – bees for cucurbits
• Food sources – part of the food chain
• Biological control agents for weeds
and other insects
• E h
Enhance soil properties
il ti
• Aesthetic value
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7. 2/15/2009
Parasitoid Wasps
Braconid emerging from moth cocoon
Ichneumonid
Ichneumonid
Image Source:
AMNH
Braconid pupae on tomato hornworm
Parasitoid Wasps Parasitized Insects
Aphid Mummies
Parasitized Cabbage Moth Larvae
Ptermomalid Wasp
Eulophid Wasp Parasitized Beetle Larvae
Parasitoid Emerging from
Aphid Mummy
Aphelenid Wasp Encyrtid Wasp
Augmentative Biological Control Conservation Biological Control
• Increases the abundance of natural enemies where the habitat
• Increase local abundance of predators and has been manipulated (Langellotto and Denno 2004)
parasitoids by releasing the biological control
• Spatial scale of conservation biological control area influences
agents into the garden success (Langellotto and Rosenheim in prep)
• Use of biological control agents as you would a
chemical pesticide
h i l ti id Beetle Banks
Hedgerow
Stapling Egg Lacewing
Egg Cards
Cards Eggs
Field Margin
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8. 2/15/2009
Conservation Biological Control Strategies Conservation Biological Control Strategies
• Reduce Disturbance • Provide Basic Needs
– Reduce Pesticide Use on the Lawn and in the – Food
Garden – Water
– Leave an area of the garden undisturbed – no – Shelter
or low mowing, raking or pruning
Insectary Plants for Biological
Control
• Coreopsis,
Parsnip,
• Mints
• Buckwheat
• Yarrow
• Sunflowers,
Asters,
Coneflowers
• Lobelia
• Goldenrod
Chemical Control in IPM Organic and Synthetic
• IPM permits integrated use of chemical • Organic: Derived from an
pesticides, but also actively seeks to minimize organic source
applications – Botanicals (pyrethrum
NeemTM, RotenoneTM)
• REDUCE – spray when needed, and not – Microbials (Bt sprays)
according to schedule
g – Naturalytes (SpinosadTM)
• REPLACE – use other, less toxic alternatives to
pesticides
• Synthetic: Manufactured
• REDESIGN – correct past landscape design pesticides
issues to reduce pest problems
Organic
Pyrethrin
Synthetic
Pyrethroid
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9. 2/15/2009
Organic Fungicides Organic Pesticides
• Azadirachtin- Neem
• Horticultural oils • Bt- biological
• Copper based • Beauveria- biological
• Horticultural oils
• Sulfur • Insecticidal soap
• Serenade (Bacillus subtilus) • Iron phosphate slugs
phosphate-
• Kaolin clay
• Baking soda (K) • Lime Sulfur
This is a peach tree
• Pyrethrins
grafted with two curl • Rotenone
resistant cultivars. Cultivar • Spinosad
'Q 1-8' on the left and the
cultivar 'Mary Jane' (with
• Sulfur
lots of curl) on the right. 2008 PNW Insect page 389
Materials Allowed for Organic Disease Orange = Biological
Management- PNW Disease
Synthetic Pesticides Organic Pesticides
Class Mode of Range of Notes Class Mode of Range of Notes
Action Activity Action Activity
Organophophates Cholinesterase Broad Potential non-target effects on Microbials – Bt** Stomach Narrow – (Bt-k) Must be ingested in order to be
Inhibitor mammals, beneficial insects a poison. caterpillars, (Bt-t) effective. Thus, targets only those
concern Paralyzes beetles, (Bt-i) - insects that are feeding on the
Carbamates Cholinesterase Broad – Chewing Potential non-target effects on insect gut. Flies protected plant.
Inhibitor
I hibit Insects
I t beneficial i
b fi i l insects a concern,
t Microbial
Mi bi l Overexcites
O it Leaf Ch
L f Chewers, Low t i it t mammals and
L toxicity to l d
mammals Derivitives – nervous Thrips, some Gall beneficial insects.
Pyrethroids Impacts Ion Broad Low toxicity to mammals, birds. Spinosad** system Makers
Channels Toxic to fish. Potential non-target Horticultural Oils** Smothering Effective against Low toxicity and minimal impacts
effects on beneficial insects. (block many insects – on non-target insects.
Neonicitinoids Impacts Ion Broad – Systemic. Low toxicity to mammals. spiracles) active stages and
Channels Homoptera and Potential non-target effects on eggs
beetles beneficial insects, especially bees. Insecticidal Soaps** Disrupts cuticle Small, soft-bodies Vertebrates and non-target insects
insects and mites generally not impacted. Toxic
against beneficial mites. May
directly harm plant
Organic Pesticides Broad Spectrum / Non-Selective
Class Mode of Range of Notes • Controls a wide range of pest organisms
Action Activity
Botanical Impacts Ion Many insects, but Low toxicity to mammals. Rapid
– Organophosphates (a.i. malathion)
Insecticides - Channels particularly useful break down in sun. Degradation
pyrethrum against limits impact on beneficial insects,
– Carbamates (a.i. carbaryl, methomyl)
caterpillars, sawfly but may require repeat application.
larvae,
larvae leaf – Pyrethroids (
y (a.i. cyfluthrin, fenpropathrin)
y p p )
beetles,
leafhoppers – Neonicotinoids (a.i. imidacloprid)
Botanical Inhibits Effective against a Low toxicity to mammals. Low risk
Insecticides - neem feeding, limited range of to beneficial insects.
interferes with insects.
molting and
egg production
Examples of Broad
Spectrum
Information for Tables Taken From:
Whitney Cranshaw. Classes of Pesticides Used in Landscape/Nursery Insecticides
Pest Management. In Chapter 9 of Tactics and Tools for IPM.
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10. 2/15/2009
Narrow Spectrum / Selective Organic Herbicides
• Controls a narrow range of pest organisms • Acetic acid (vinegar-based)
• Clove/citric acid based
– Insect Growth Regulators (IntrepidTM),
• Herbicidal Soap
– Bacillus thuringiensis (B.t.), Bt-k (DipelTM) and – Contact
Bt-t (NovodorTM) – Non-selective
– Do not translocate
– OK for annuals
– Perennials- hmmm
Colorado potato beetle • Corn gluten
Leptinotarsa decemlineata. – Pre-emergent
Bt-t toxin is effective against – Not effective
– Good N fertilizer
This pest of potatoes, tomatoes
and other solanaceous crops
Minimizing the Negative Effects of
Chemical Control
Chemical Control
• Although chemical control should be the • Avoid applying pesticides on a windy day.
last tactic considered, it may be the only
way to quickly and effectively keep a • Choose narrow over broad spectrum
particular pest in check. insecticides.
• Used correctly pesticides are indispensable
correctly, • Spot treat, rather than broadcast a
p
tools of an IPM program pesticide.
• Incorrect use of pesticides can lead to: • Always read the label, follow directions and
do not apply more than is recommended.
– pest resistance to the pesticide
– outbreaks of secondary pests • Wear protective clothing and eyewear.
– adverse effects on nontarget organisms • Dispose of unwanted pesticides and empty
– direct hazards to the user containers properly.
Summary
• There is no true silver bullet
– Pesticides come with pros and cons
– Alternatives to pesticides come with pros and
cons
• Conservation biological control is the best,
long term pest management strategy
available to home gardeners
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