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

Organic Pest Management:Emphasizes Preventative Practices

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

Soil Quality ManagementDoes it affect above-ground pest damage?

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

`Prince Hairy’ PotatoFrom Cornell Breeding Program

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

Int’l. Organic Research Institute in Switzerland

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

Biocontrol Agent Success in Commercial Greenhouses

Predatory Mites & Orius spp.

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

Of Less ImportanceEntomopathogenic Fungi and Nematodes

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 & Kill

Products mix pest attractants (pheromones) with insecticide

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