Planning an Insect Pest Management System from the Ground Up (with examples from organic research)

1. Planning an Insect Pest Management System from the Ground Up(with examples from organic research) Geoff Zehnder, Sustainable Agriculture Program, Clemson University zehnder@clemson.edu Research Institute of Organic Agriculture, FiBL, Switzerland

2. 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.

3. Integrated Pest Management • Concept developed in the 1950s • Early proponents emphasized ecological approaches for more permanent solutions • Conventional agriculture • Reactive approaches dominate • Pesticides are relatively cheap (ecological and societal costs not factored) • “IPM Continuum” culminates in biologically based strategies

4. Organic Pest Management:Emphasizes Preventative Practices

5. 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

6. Strategies Underlying 1st Phase Practices

7. 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

8. Crop Isolation/Rotation • Most effective against pests that disperse short distances and/or that overwinter near host crop fields. Colorado potato beetle Carrot fly Onion maggot Learn about key pest (insect and disease) host range and biology/behavior to help with crop rotation plan

9. Woody Borders • Modeling studies indicate that woody field borders influence insect pest populations: • Habitat for natural enemies • Can inhibit movement of pests into fields

10. 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)

11. Rotation with Cover Crops • Beneficial, but be aware of secondary effects • Allelopathy; may suppress crop growth • Examples; barley, oat, wheat, rye, canola, mustards, fescues, • May harbor secondary pests • i.e. wireworms attracted to grass cover crops

12. Rotation with Biofumigation Crops • Brassica crops (mustards, rape, etc.) • Plant defense compounds • Glucosinolates converted to isothiocyanates • Soil concentrations high enough to kill pathogens, weed seeds, soil insects

13. Soil Quality ManagementDoes it affect above-ground pest damage?

14. 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)

15. European Corn Borer Infestation Reduced on Plants Grown in Organic Soils • Compared egg-laying on plants grown in soil from organic vs conventional farms • Significantly more ECB eggs laid on plants in conventional soil • Egg-laying was more variable on plants in conventional soils. • Variability in egg-laying affected by plant mineral balance • Hypothesis: biological buffering in org. soils Research by Dr. Larry Phelan; Ohio State University

16. Reduced development of Colorado potato beetle on potato grown in organic soil Research by Alyokhin & Atlihan, 2005

17. 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

18. 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 % Plants Infected with WMV

19. Conservation tillage • Favors rich soil biota • Greater abundance and diversity of soil microbes in conservation tillage • Favors greater numbers of predatory arthropods (spiders, beetles)

20. 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

21. `Prince Hairy’ PotatoFrom Cornell Breeding Program

22. 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

23. Second Phase StrategiesVegetation Management • Make habitat less suitable for pests; attractive to natural enemies • Terms include: • Habitat enhancement • Farmscaping • Ecological Engineering • Conservation biological control • Intercropping • Trap Cropping

24. 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.

25. Beetle BanksIsland Habitats on Farms • Permanently vegetated raised strips across fields (grasses, perennials). Refuge for • Predatory beetles • Spiders • Birds • Small mammals • Primarily used in large fields (cereal, row crops) • Winter home for > 1000 predatory invertebrates per square meter (Thomas et al. 1992)

26. Conservation Strips • Mixture of forbs and grasses • Combines “beetle bank” and “insectary strip” concepts • Increases rates of predation • Management of weed strips can be used in this context

27. Int’l. Organic Research Institute in Switzerland

28. Flowering Insectary Strips • Provides pollen and nectar • Attracts and keeps natural enemies in area • `Provisioned’ natural enemies have increased longevity, fecundity

29. Evaluation of Wildflower Strips to Enhance Biocontrol in CabbagePfiffner et al. 2003 • Treatments • 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

30. Chocolate-box Ecology? • Flowering plants added without prior testing • Parasitic wasps visit an ave. of only 2.9 plant species • Researchers now screen plants for optimal species • Farmers collect info on key pests, natural enemies to design effective farmscapes • www.attra.org

31. Intercropping • `Resource concentration’ hypothesis (Root 1973) • Concentrated areas of host plants are easier for insect pests to find and colonize • Interferes with pests in a `bottom-up’ manner

32. 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

33. Third Phase StrategiesRelease of Biological Control Agents • Predators, parasitoids • Microbial agents • Selectivity • Allow for rapid response to pest problems • Most research in greenhouse systems

34. Biocontrol Agent Success in Commercial GreenhousesPredatory Mites & Orius spp.

35. Release of Biocontrol Agents in Field-Grown Organic CropsExperimental Successes • Parasitoids • caterpillars in vegetables, aphids in wheat, leafhopper in vineyards • Mite, ladybug and lacewing predators • spider mites, aphids and leafhoppers in vineyards and apple orchards

36. Release of Biocontrol Agents in Field-Grown Organic CropsExperimental Failures Cherry fruit fly on sweet cherry Grape mealybug on grape Incompatible life histories of pest and biocontrol agent, or disruption of agents by other natural enemies

37. 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

38. Biocontrol LandmarkCodling Moth Granulosis Virus • Isolated from codling moth in 1963 • Europe • 1979: Apple Biological Control Program • Three commercial formulations; widely used • U.S. • Two commercial formulations; little use

39. Of Less ImportanceEntomopathogenic Fungi and Nematodes

40. 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 techniques • Small companies; limited technology • Suboptimal quality in past but improving • But used regularly in organic farming • Research needed on how to integrate use of biocontrol agents with other strategies

41. 4th Phase Strategies • Insecticides of biological, mineral origin • Pheromones • Repellents • Mineral oils, insecticidal soaps • Non-synthetic origin (except pheromones)

42. Organic Insect Control ProductsCurrent 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 materials • Fermentation product of bacterium Saccharopolyspora spinosa • Successfully tested worldwide against a variety of pests/crops

43. 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

44. Kaolin Clay • Surround WP™ • Used as a repellent; alters feeding, oviposition behavior of insect pests • Most use in tree fruit, grapes

45. 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

46. Limits of OMRI-Approved Insecticides, etc • Degrade quickly; low potency; short residual activity • Must integrate with other strategies • More research needed • Develop treatment thresholds for organic systems where natural enemies are prevalent • Commercial development • EPA; fast-track registration • Limited by markets

47. Organic Insect Pest Management:Future Directions Integration of tactics; i.e. 2nd and 3rd phase strategies; Example: Egg parasite: Longevity and survival enhanced by nectar plants Pest: Brown apple moth

48. Attract & Kill • Products mix pest attractants (pheromones) with insecticide

49. Attract & Reward • Attract (4th phase) • Lures with synthetic plant volatiles • Attract beneficial insects • Reward (2nd phase) • Pollen, nectar plants • Enhance level of pest control

50. 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).