2/15/2009 1 Home Garden Seminar Josephine County Master Gardeners Josephine County Master Gardeners Alternatives to Pesticides Gail Langellotto Urban and Community Horticulture Specialist OSU Extension and Department of Horticulture Number of Species Currently Controlled with Pesticides Diseases 137 Insects 304 Mites 34 Nematodes 23 Weeds 102 Agricultural Effects upon Diversity Equilibrium 0 10 20 30 40 versity -40 -30 -20 -10 Di v Pristine "Natural" Conventional Agriculture Alternative Agriculture Conservation Biological Control • Few studies have been conducted in garden systems – Exception: Shrewsbury and Raupp (2006). Do top-down or bottom up forces determine Stephanities pyriodes in urban landscapes? Two Dimensional System Three Dimensional System • Raupp et al. 2001. Plant species diversity and abundance affects the number of arthropod pests in residential landscapes. Land Components Abiotic Plant Disease Complex Landscape Ecology Pest Complex Land Natural Enemies Management Soil Abiotic Factors Plant Diversity Organic Matter Nutrients Soil Nematodes Microbial Flora Micro/ Macro Inverte- brates
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Alternatives to Pesticides - Urban and Community Horticulture
Alternatives to Pesticides - Urban and Community Horticulture
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Home Garden SeminarJosephine County Master GardenersJosephine County Master Gardeners
Alternatives to PesticidesGail Langellotto
Urban and Community Horticulture Specialist
OSU Extension and Department of Horticulture
Number of Species Currently Controlled with Pesticides
• Improper planting often results in stressed plants.
• Compacted soils are often a particular problem on home sites.problem on home sites.
Planting container plants
• Container plants with circling roots or that are root-bound should have these problems corrected prior to planting.
Root Preparation Prior to Planting
• Thoroughly preparing the roots prior to planting on root-bound pots usuallybound pots usually improves growth immediately as well as plant survival
Planting container plants
• Size of planting hole
• Depth of planting
• Finish by watering the plant in well
• Time of planting
Cultural Control: Plant Maintenance
• Water for deep, spread roots
• Fertilizing– Too much fertilizer can increase insect pest
problems as much as too little fertilizer.
• 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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Disease Management: Sanitation
• Clean up Debris
Physical/Mechanical Control
• Use of physical barriers, machines or objects to prevent an infestation (preventative), or kill the pest (remedial)
Horticultural fabrics to cover plants– Horticultural fabrics to cover plants (preventative)
– Flyswatter (remedial)
Physical Control of Weeds
• A sharp hoe and lots o’ diligence• Mulch!• Cover crops• Crop rotationCrop rotation • Whenever possible prevent weeds from
going to seed
Weed Management
• Weeds are easier to kill when they are very small – “white thread” to 2-3 true leaves.
• Mechanical weeding is more effective during warm, dry, windy weather. Plants can re-root in cool et eathercool wet weather.
• In the Vegetable Garden or Home Orchard-– Control weeds early in crop growth
– Cover crops can reduce subsequent weed pressure
Weed Management
• Weeds are easier to kill when they are very small – “white thread” to 2-3 true leaves.
• Mechanical weeding is more effective during warm, dry, windy weather. Plants can re-root in cool et eathercool wet weather.
• Control weeds early in crop growth
• Cover crops can reduce subsequent weed pressure
Physical Control: Sticky barrier
• Can prevent pests from climbing and colonizing tree.
• Can prevent pests from climbing down tree to pupate in soil
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Copper Barriers for Molluscs
Brown Garden Snail
Physical Control: Collars and Cages
Tin CollarCutworm Control
Plant Cage on RadishesCabbage Maggot Control
Physical Control: Row Covers
• Covers many plants, or entire rows
• Protection for seedlings, or during other lnerable timesother vulnerable times
• Light, thermal and air environment will be modified
Handpicking
Place insects in soapywater to kill them
Spray plants with water to dislodge aphids.
Aphids
Water Sprays
Spider
Mites
Spider mites
p
Must be sprayed regularly to prevent recolonization.
Aphids
Pruning
Tent caterpillars
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Boxelder Bug Flea
Vacuuming
Asian Ladybug Beetle
Tilling
Tilling
Garden symphylan
Physical Control: Bug Zappers
Royal Walnut Mothsitting on a bug zapper
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)(conservation) or applied (augmentative).
The 3 P’s: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 il ti• Enhance soil properties
• Aesthetic value
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Braconid emerging from moth cocoon
Ichneumonid
Ichneumonid
Parasitoid Wasps
Image Source:AMNH
Braconid pupae on tomato hornworm
Ichneumonid
Parasitoid Wasps
Eulophid Wasp
Aphelenid Wasp Encyrtid Wasp
Ptermomalid Wasp
Parasitized Insects
Aphid Mummies
Parasitized Cabbage Moth Larvae
Parasitized Beetle Larvae
Parasitoid Emerging from
Aphid Mummy
Augmentative Biological Control
• Increase local abundance of predators and parasitoids by releasing the biological control agents into the garden
• Use of biological control agents as you would a h i l ti idchemical pesticide
Stapling EggCards Egg Cards
Lacewing Eggs
Conservation Biological Control
• Increases the abundance of natural enemies where the habitat has been manipulated (Langellotto and Denno 2004)
• Spatial scale of conservation biological control area influences success (Langellotto and Rosenheim in prep)
Beetle BanksBeetle BanksHedgerow
Field Margin
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Conservation Biological Control Strategies
• Reduce Disturbance– Reduce Pesticide Use on the Lawn and in the
Garden
– Leave an area of the garden undisturbed – no or low mowing, raking or pruning
Conservation Biological Control Strategies
• Provide Basic Needs– Food
– Water
– Shelter
Insectary Plants for Biological Control
• Coreopsis, Parsnip,
• Mints
• Buckwheat
• Yarrow
• Sunflowers, Asters, Coneflowers
• Lobelia
• Goldenrod
Chemical Control in IPM
• IPM permits integrated use of chemical pesticides, but also actively seeks to minimize applications
• REDUCE – spray when needed, and not according to scheduleg
• REPLACE – use other, less toxic alternatives to pesticides
• REDESIGN – correct past landscape design issues to reduce pest problems
Organic and Synthetic
• Organic: Derived from an organic source– Botanicals (pyrethrum
• Baking soda (K)This is a peach tree grafted with two curl resistant cultivars. Cultivar 'Q 1-8' on the left and the cultivar 'Mary Jane' (with lots of curl) on the right.
Materials Allowed for Organic Disease Management- PNW Disease
Do not translocate– Do not translocate– OK for annuals– Perennials- hmmm
• Corn gluten– Pre-emergent– Not effective– Good N fertilizer
Chemical Control
• Although chemical control should be the last tactic considered, it may be the only way to quickly and effectively keep a particular pest in check.
• Used correctly pesticides are indispensable• Used correctly, pesticides are indispensable tools of an IPM program
• Incorrect use of pesticides can lead to:– pest resistance to the pesticide – outbreaks of secondary pests– adverse effects on nontarget organisms – direct hazards to the user
Minimizing the Negative Effects of Chemical Control
• Avoid applying pesticides on a windy day.• Choose narrow over broad spectrum
insecticides.• Spot treat, rather than broadcast a p
pesticide.• Always read the label, follow directions and
do not apply more than is recommended.• Wear protective clothing and eyewear.• Dispose of unwanted pesticides and empty
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