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Planning an Insect Pest Management System from the Ground Up
(with examples from organic research)
Planning an Insect Pest Management System from the Ground Up
(with examples from organic research)
Research Institute of Organic Agriculture, FiBL, Switzerland
Geoff Zehnder, Sustainable Agriculture Program, Clemson University
zehnder@clemson.edu
Integrated Pest Management (IPM)
Integrated pest management (IPM) is a pest control strategy that uses a variety of complementary strategies including: biological
and cultural management, mechanical and physical controls, and genetic and pesticides when needed (source: Wikipedia).
Interesting fact: For their leadership in developing and spreading IPM worldwide, Dr. Perry Adkisson (Texas A&M) and Dr. Ray Smith (UC Berkeley) received the 1997 World Food Prize.
Integrated Pest Management
Concept developed in the 1950sEarly proponents emphasized ecological approaches for more permanent solutionsConventional agriculture
Reactive approaches dominatePesticides are relatively cheap (ecological and societal costs not factored)“IPM Continuum” culminates in biologically based strategies
1st Phase Strategies(Foundation of Organic Pest Management)
Cultural practices implemented in the initial stages of organic farm planning
Prevent and avoid problems beforehand
Have roots in traditional agriculture
Strategies Underlying 1st Phase Practices
Strategy Example
Make crop unavailable to pests in space/time
Site selection, crop isolation, timing of planting/harvest, etc
Make crop unacceptable to pests
Intercropping, trap cropping, mulching
Reduce pest survival by enhancing natural enemies
Increase crop ecosystem diversity; farmscaping
Alter crop susceptibility to pests
Host plant resistance/tolerance; soil quality, fertility
Farm Site Selection
Pest management not usually most important consideration, but
Many organic farms are located in regions where climate is unfavorable for pest outbreaks
Example: plum curculio
In general, higher, cooler
and dryer regions support
fewer insect pests
Crop Isolation/Rotation
Most effective against pests that disperse short distances and/or that overwinter near host crop fields.
Carrot fly Colorado potatobeetle Onion maggot
Learn about key pest (insect and disease) host range and biology/behavior to help with crop rotation plan
Woody Borders
Modeling studies indicate that woody field borders influence insect pest populations:
Habitat for natural enemies
Can inhibit movement of pests into fields
Isolation of Susceptible CropsIn Space or Time
Insect transmitted virus diseases
Depending on the virus/vector, new crops should be isolated from sources of inoculum (infested fields, weed hosts, etc)
Rotation with Cover Crops
Beneficial, but be aware of secondary effects
Allelopathy; may suppress crop growthExamples; barley, oat, wheat, rye, canola, mustards, fescues,
May harbor secondary pestsi.e. wireworms attracted to grass cover crops
Rotation with Biofumigation Crops
Brassica crops (mustards, rape, etc.)
Plant defense compoundsGlucosinolates converted to isothiocyanates
Soil concentrations high enough to kill pathogens, weed seeds, soil insects
Organic farming proponents have long held the view that the likelihood of pest outbreaks is reduced in “healthy soil”
Sir Albert Howard. 1940.
RC Oelhaf. 1978
MC Merrill. 1983
•Belowground and aboveground habitat management is equally important
•Plant resistance is linked to optimal physical, chemical and biological properties of soil
Miguel Altieri (UC Berkeley)
European Corn Borer Infestation Reduced on Plants Grown in Organic Soils
Compared egg-laying on plants grown in soil from organic vs conventional farmsSignificantly more ECB eggs laid on plants in conventional soilEgg-laying was more variable on plants in conventional soils. Variability in egg-laying affected by plant mineral balanceHypothesis: biological buffering in org. soils
Research by Dr. Larry Phelan; Ohio State University
Reduced development of Colorado potato beetle on potato grown in organic soil
Research by Alyokhin & Atlihan, 2005
Mulch: an IPM tool
Can help reduce problems with:
Colorado potato beetle
Aphid and thrips transmitted viruses
May exacerbate some insect problems
Squash bug
Planthopper
Melon-Virus ExperimentsCover crop as camouflage
Annual rye planted between rows in late fall
Virus incidence lower in cover crop treatments
Reflective mulch also reduced virus incidence
0
50
100
2003 2004
Cover
No Cover
% Plants Infected with WMV
Conservation tillage
Favors rich soil biota
Greater abundance and diversity of soil microbes in conservation tillage
Favors greater numbers of predatory arthropods (spiders, beetles)
Host Plant Resistance
Resistance vs. Tolerance
Limited application for control of insect pests in conventional agriculture
Efficacy of synthetic insecticides
Low tolerance for cosmetic damage
Partial plant resistance not acceptable
Whitefly Damage: Hairy vs. Smooth Leaf Cotton
Corn Earworm:
Can’t easily penetrate tight husk varieties
Moderate HPR is preferable in sustainable/organic systems
Low-level pest densities support natural enemy populations
Manipulate planting and harvest dates for optimum effect
Demand may provide commercial incentives for seed companies to expand screening programs
Second Phase StrategiesVegetation Management
Make habitat less suitable for pests; attractive to natural enemies
Terms include:
Habitat enhancement
Farmscaping
Ecological EngineeringConservation biological control
Intercropping
Trap Cropping
Plant Diversification
Provides food and shelter for natural enemies (predators and parasites)
Favorable microclimate
Alternative hosts or prey
Supply of nectar and pollen
Enhances “top-down” action of natural enemies on pests.
Beetle BanksIsland Habitats on Farms
Permanently vegetated raised strips across fields (grasses, perennials). Refuge for
Predatory beetlesSpidersBirdsSmall mammals
Primarily used in large fields (cereal, row crops)Winter home for > 1000 predatory invertebrates per square meter (Thomas et al. 1992)
Conservation Strips
Mixture of forbs and grassesCombines “beetle bank” and “insectary strip” conceptsIncreases rates of predationManagement of weed strips can be used in this context
Flowering Insectary Strips
Provides pollen and nectar
Attracts and keeps natural enemies in area
`Provisioned’ natural enemies have increased longevity, fecundity
Evaluation of Wildflower Strips to Enhance Biocontrol in Cabbage
Pfiffner et al. 2003Treatments
Strips adjacent
Strips 10-90 meters
Cabbage with no strips
Higher rate of parasitism next to strips
Parasitism increased with proximity to strips
Scale/size of strips relative to crops important
Chocolate-box Ecology?
Flowering plants added without prior testingParasitic wasps visit an ave. of only 2.9 plant speciesResearchers now screen plants for optimal speciesFarmers collect info on key pests, natural enemies to design effective farmscapeswww.attra.org
Intercropping
`Resource concentration’ hypothesis (Root 1973)Concentrated areas of host plants are easier for insect pests to find and colonizeInterferes with pests in a `bottom-up’ manner
Trap Cropping
Attractiveness and relative size in the landscape are key factors
Examples:
Blue Hubbard around summer squash; Pumpkins around melons (cuc. beetle)
Cherry peppers around bell pepper (pepper maggot)
Collards around cabbage (DBM)
Top; Sam Pair, USDA-ARS, Lane, OK
Bottom: Randy Blackmer, Dale, CT
Third Phase StrategiesRelease of Biological Control Agents
Predators, parasitoids
Microbial agents
Selectivity
Allow for rapid response to pest problems
Most research in greenhouse systems
Release of Biocontrol Agents in Field-Grown Organic Crops
Experimental Successes
Parasitoidscaterpillars in vegetables, aphids in wheat, leafhopper in vineyards
Mite, ladybug and lacewing predatorsspider mites, aphids and leafhoppers in vineyards and apple orchards
Release of Biocontrol Agents in Field-Grown Organic Crops
Experimental Failures
Cherry fruit fly on sweet cherry
Grape mealybugon grape
Incompatible life histories of pest and biocontrol agent, or disruptionof agents by other natural enemies
Biocontrol LandmarkBacillus thuringiensis
1901; Silkworm “sudden collapse” disease
1911: Named by Ernst Berliner (Thuringia)
Farmer use in 1920s France; Sporine
EPA registration in 1961
Thousands of strains active against caterpillars, beetles, flies
Toxin attacks gut cells Bt spore crystals; Courtesy of Rosemary Walsh, EMF-LSC, Penn State
Biocontrol LandmarkCodling Moth Granulosis Virus
Isolated from codling moth in 1963Europe
1979: Apple Biological Control ProgramThree commercial formulations; widely used
U.S. Two commercial formulations; little use
Why is Use of Biological Control Agents Limited?
Commercial development restricted only to those with potential market for large acreage crops
Many effective agents for less important pests never pass beyond developmental stage
Mass rearing techniquesSmall companies; limited technologySuboptimal quality in past but improving
But used regularly in organic farmingResearch needed on how to integrate use of biocontrol agents with other strategies
4th Phase Strategies
Insecticides of biological, mineral origin
Pheromones
Repellents
Mineral oils, insecticidal soaps
Non-synthetic origin (except pheromones)
Organic Insect Control Products
Current Trends in Organic Farming
Reduced pyrethrin use; non-target effects
Azadirachtin (neem) use is increasing Successful experiments against several pests including aphids and some chewing insects
Spinosad one of few new approved materialsFermentation product of bacterium Saccharopolyspora spinosa
Successfully tested worldwide against a variety of pests/crops
Quassia Extract (bitter wood)Quassia amara
Many active compunds; alkaloids, triterpenes and bitter principles (quassin)
50X more bitter than quinine; herbal remedy
Used mostly in Europe:Mosquito larvacide
To control aphids in cereal crops
To control wooly apple aphid in tree fruit
Kaolin Clay
Surround WP™
Used as a repellent; alters feeding, oviposition behavior of insect pests
Most use in tree fruit, grapes
Specialized Application
Dropleg application of Bacillus thuringiensis var. kurstaki against lepidopterans in leek. The application from top and
bottom increases efficacy of Bt applications. Photo: Eric Wyss, FiBL
Limits of OMRI-Approved Insecticides, etc
Degrade quickly; low potency; short residual activity
Must integrate with other strategies
More research neededDevelop treatment thresholds for organic systems where natural enemies are prevalent
Commercial developmentEPA; fast-track registrationLimited by markets
Organic Insect Pest Management:Future Directions
Integration of tactics; i.e. 2nd and 3rd phase strategies; Example:
Pest: Brown apple moth
Egg parasite: Longevity and
survival enhanced by nectar plants
Attract & Reward
Attract (4th phase)Lures with synthetic plant volatiles
Attract beneficial insects
Reward (2nd phase)Pollen, nectar plants
Enhance level of pest control
Valuing Ecosystem Services
“Ecosystem services are the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life (Daily 1997).”
The value of global Ecosystem Services estimated at $33 trillion (Costanza et al., 1997).
Dr. H.S. SandhuLincoln University, New Zealand
1. Assessing the predation rate of aphids (Acyrthosiphon pisum Harris)
2. Assessing the predation rates of blow fly eggs (Calliphora vicina R.D.) simulating carrot rust fly eggs (Psila rosae Fab.)
Experimental assessment of ES in arable fields
29 Study Sites (14 Organic and 15 Conventional fields)
(a) (b)
Fig. (a) Map of New Zealand study area (Canterbury). (b) Location of selected arable organic ( ) and conventional fields ( )
N
Ashburton
Rakaia river
Leeston
Lincoln
Predation rates of aphids and fly eggs in
selected arable fields
Fig. Predation rates (%removal/24h) of aphids and fly eggs in selected fields
Ground living polyphagous predators:
Are they any value?
Dollar value of biological control of aphids in selected organic fields
More Information
More information on insect management for organic farms can be found at:
•http://attra.org/pest.html
•http://www.extension.org/article/18593
•http://www.sare.org/publications/insect.htm
Acknowledgements
This presentation address general organic production practices. It is to be to use in planning and conducting organic horticulture trainings. The presentation is part of project funded by a Southern SARE PDP titled “Building Organic Agriculture Extension Training Capacity in the Southeast”Project Collaborators•Elena Garcia, University of Arkansas CESHeather Friedrich, University of ArkansasObadiah Njue, University of Arkansas at Pine BluffJeanine Davis, North Carolina State UniversityGeoff Zehnder, Clemson UniversityCharles Mitchell, Auburn UniversityRufina Ward, Alabama A&M UniversityKen Ward, Alabama A&M UniversityKaren Wynne, Alabama Sustainable Agriculture Network
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