Insect Management Options in Organic Farming

1
Insect Management Options in Organic Farming

• Phil Mulder
• Professor, Interim Dept. Head, Dept. Extension
  Coordinator and Extension Entomologist
• Department of Entomology and Plant Pathology
  Oklahoma State University
• Oklahoma Cooperative Extension Service

2
Limitations under the USDAs National Organic
Program (NOP)

• Ingredients must be natural substances, or
  synthetics included on the National List (7CFR
  205.600-205.607).
• Some natural substances are also prohibited
  (inert ingredients may be prohibited in some
  cases See EPA List 4A or 4B).
• All substances must be approved by the Organic
  Materials Review Institute (OMRI) and/or the
  state certification agency.
• Further restrictions require preventative,
  cultural, and physical methods (includes release
  of beneficial insects) must be the first choice
  for pest control. If ineffective, a botanical,
  biological or synthetic on the national list may
  be used, if conditions are documented in the
  organic farm plan.
• This requirement reflects an historic practice
  relying on the use of biological and cultural
  practices such as crop rotation,
  diversification, habitat management, beneficial
  organism releases, sanitation, and timing before
  resorting to limited use of permitted pest
  control substances.

3
Procedures and Methods in Adopting an Organic
Management Plan

• Understand the pests and beneficial organisms
  that usually occur in the crop and anticipate the
  pest problems likely to occur.
• Pests more effectively controlled when numbers
  are low and early in their life cycles.
• Pay attention to crop rotations and crop residue
  incorporation, to avoid buildup in pest species.
• What varieties or crops to grow
• When to plant, to avoid pest problems
• Good recordkeeping on pest problems builds a
  foundation for next seasons pest control
  strategies.

4
Procedures and Methods (continued)

• Correctly identify the pests and beneficial
  organisms present and note when they occur most
  commonly.
• Helps alert a grower to potential problems before
  crop losses occur.
• Use pheromones and other trapping methods when
  available for key pests, to determine timing of
  population cycles and predict local increases in
  activity.
• Some cases where mating disruption can be used to
  prevent successful mating, and reduce subsequent
  damaging populations (e.g. fruit and nut pests).
  

5
Procedures and Methods (continued)

• Make frequent or at least weekly checks for pest
  activity.
• Use a sweep net, hand lens, drop cloth.
• Inspect the underside of leaves.
• Identify tolerable levels (action thresholds) for
  pest activity in specific crops.
• Pests feeding directly on the consumable product
  can be tolerated much less than defoliators in
  most cases.

6
Specific Methods for Managing Arthropod Pests
Organically

• Cultural control
• Mechanical control
• Biological control
• Chemical control

7
Cultural Control

• Coordinate planting and harvest dates to avoid
  certain pests.
• Sweet corn and corn earworm
• Plant later crops upwind of early crops or plant
  them in isolated fields.
• Use non-susceptible cover crops to improve
  fertility and provide a source of organic matter.
  
• Incorporate a grass species into a rotation,
  these tend to be resistant to many insect and
  disease pests of common cash crops.

8
Cultural Control (continued)

• Plant field borders or strips within the field of
  species or varieties that are different from the
  main crop
• Flowering plants along borders of fields can
  provide habitat and food for beneficial insects.
• Maintain a trap crop in a vigorous state, so
  pests may never want to leave
• Spray the trap crop if they start to leave (e.g.
  pearl millet)
• Manage overwintering sites for many of the true
  bugs (stink bugs, squash bugs, alfalfa weevils,
  etc.)
• Lumber, box piles, storage buildings, weedy field
  borders, etc.

9
Mechanical Control

• Soil Tillage and organic matter decomposition
• Allow a longer fallow period before planting,
  exposes insects to predators (e.g.- birds) or
  removes food supply for cutworms, wireworms, root
  maggots and certain mites.
• Handpicking and vacuuming certain insect pests in
  small plantings is quite effective
• Tomato hornworms, lygus bugs, squash bugs, etc.
• Pest barriers can help in high value crops.
• Floating row covers, plastic tunnels, reflective
  mulches

10
Biological Control

• Many beneficial organisms help regulate pest
  numbers in nature without the aid of chemicals.
• When naturally occurring biological control is
  not adequate for maintaining a pest below levels
  that cause losses, biological control can
  sometimes be increased .
• Classical biological control, Augmentation,
  Conservation and enhancement.

11
Classical Biological Control

• Deliberate introduction and establishment of
  exotic natural enemies into areas where they did
  not exist.
• Usually against invasive species.
• Several steps in doing this properly include
• ID the pests native range, search its native
  range for candidates, ship them into quarantine
  facilities for study to exclude contaminants and
  confirm that no negative impacts exist in the new
  country, then finally increase their numbers
  before release.
• Only Government agencies or University
  Experiment Stations
• 100s of insect and weed examples have been
  successful.
• Vedalia beetle on cottony cushion scale, musk
  thistle weevil on musk thistle, cactus moth on
  prickly pear cactus, etc.

12
Augmentation

• Supplementing the numbers of naturally occurring
  natural enemies with releases of lab-reared or
  field collected natural enemies.
• Inoculative release building up populations of
  natural enemies earlier than normal, or
  establishing it where it is not present.
• Releasing predatory mites in almonds or
  strawberries, mosquito fish in rice fields to
  control mosquitoes, release of bindweed mites to
  control bindweed in wheat, etc.

13
Augmentation (Continued)

• Supplementing the numbers of naturally occurring
  natural enemies with releases of lab-reared or
  field collected natural enemies.
• Inundative release periodic releases of natural
  enemies with no expectations of establishment.
  So. additional releases will be required
  throughout the season
• Releasing Trichogramma wasps for controlling
  caterpillar pests, release of whitefly
  parasitoids (Encarsia) in the greenhouse,
  entomopathogenic nematodes used against several
  soil dwelling insects, etc.

14
Tips for Releasing Beneficials

• Be sure to release a sufficient amount.
• Make sure adequate water is available before the
  release.
• Release organisms at sundown, to allow them time
  to find a safe harborage
• Release in specific locations where infestations
  are present.
• Use cages and/or beneficial insect meal to keep
  insects around if pests are not present in
  sufficient numbers.
• Provide additional habitat when possible
  (includes flowering plants and clover mixes).

15
Conservation and Enhancement

• Modifying or enhancing the local environment to
  conserve beneficial species or enhancing their
  activities.
• Increasing plant diversity in the ecosystem (e.g.
  reduce monocultures). Requires careful
  consideration of the complex interactions between
  plant and animal populations.
• Habitat manipulation with cover crops, alternate
  hosts, insectary plants, and soil supplements to
  conserve native natural enemies.

16
Chemical Control

• If organic growers choose to consider chemical
  treatment they may need to consider several
  factors including
• Mammalian toxicity, effects on beneficial
  species, adequate coverage and volume, residual
  activity.
• All organic materials, many of which are
  botanicals, are not exclusively safer than
  conventional pesticides (e.g. Nicotine is one
  the most dangerous substances known, yet it is
  considered a botanical insecticide, others like
  sulfur are good at suppressing certain disease
  problems, but may cause skin and/or eye
  irritation).
• For the organic grower wishing to conserve
  beneficial organisms, botanicals and soap-based
  products should be a last resort because of their
  broad spectrum capabilities.

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Chemical Control (continued)

• Effects on beneficial organisms
• Indirect effects through starvation of
  beneficials, which could prompt their migration
  out of the field.
• Adequate Coverage
• Requires high volumes of water (100-200 gallons
  or more per acre) with thick canopies and with
  certain materials.
• May require more nozzles and high pressure to
  produce the desired droplet size for optimum
  coverage (Electrostatic or airblast sprayers).
• Proper Timing is essential regardless of
  equipment.
• Must hit a susceptible organism at its most
  vulnerable stage.

18
Chemical Control (continued)

• Residual capacity of most organically approved
  materials is limited degrade rapidly in the
  environment.
• Repeated applications may be necessary, so
  concern over resistance, but not as great with
  short residual materials.
• In addition, pests are unlikely to develop
  resistance to materials such as oils and soaps
  that use physical actions such as suffocation and
  entrapment.

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Chemical Control (continued)

• Pests controlled by organically approved
  materials include
• Aphids oils, soaps, pyrethrum/rotenone
  combinations, kaolin clay, Pyola(canola oil
  pyrethrins) GE-derived?, garlic sprays,
  diatomaceous earth, Beauveria bassiana (Mycotrol
  O).
• May affect beneficials that are attracted to
  honeydew. Allow time for lag in beneficial
  populations before controlling aphids (e.g.
  greenbugs rarely need control past March 15 in
  southwest Oklahoma).

20
Chemical Control (continued)

• Pests controlled by organically approved
  materials include
• Whiteflies soaps and oils (many applications),
  sticky traps, seaweed powder, Beauveria bassiana
  (Mycotrol O).
• Thorough coverage under plant leaves necessary.
• First look for parasitized whitefly pupae.

21
Chemical Control (continued)

• Pests controlled by organically approved
  materials include
• Leafminers Pyrethrins, rotenone, azadirachtin
  (Neem), Entrust (spinosad).
• Sprays will slow the buildup of native wasp
  parasitoids.

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Chemical Control (continued)

• Pests controlled by organically approved
  materials include
• Leafhoppers Pyrethrins, rotenone and kaolin clay
  on nymphal stages, Beauveria bassiana (Mycotrol
  O).
• Kaolin clay (Surround ) acts as a deterrent,
  coats the plant. Leafhoppers dont like to feed
  through it or get it on their body.

23
Chemical Control (continued)

• Pests controlled by organically approved
  materials include
• Flea beetles Soaps, pyrethrin/rotenone
  combinations, sabadilla, garlic sprays,
  onionmint, Pyola(canola oil pyrethrins)
  diatomaceous earth.

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Chemical Control (continued)

• Pests controlled by organically approved
  materials include.
• Stinkbugs Difficult to control as adults with
  any materials. First two instars can be managed
  with soap sprays or Beauveria bassiana (Mycotrol
  O). Dont let these build up or cannot be
  controlled. Can use traps to monitor.

25
Chemical Control (continued)

• Pests controlled by organically approved
  materials include
• Mites sulfur sprays or dusts, mineral,
  vegetable-based, or neem seed oils, kaolin clay
  (Surround), garlic oil. Many concoctions
  including glue and buttermilk sprays.
• Oil sprays watch out if temperature and RH add
  up to more than 140 to avoid phytotoxicity.

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Chemical Control (continued)

• Pests controlled by organically approved
  materials include
• Caterpillars Bacillus thuringiensis var.
  kurstaki (Btk) Smaller worms and use thorough
  coverage practices, since ingestion of the
  material by the insects is required. Entrust,
  spinosad product quite expensive, but very
  effective.

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Brief Lesson on Bt formulations

• Make certain you are obtaining the correct
  formulation for the task.
• BtK For Lepidoptera caterpillars immature
  moths and butterflies. 2-5 prolegs including anal
  prolegs. Thuricide cost16 oz. 15.46
• Dont confuse with Hymenoptera caterpillars
  immature sawflies (wasps). More than 5 prolegs.
  Btk will not control these insects.
• Bts must be ingested (foliar feeding
  caterpillars), paralyzes and destroys the cells
  of the insect gut wall, causes septecemia.
  Degrades rapidly in sunlight.

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Brief Lesson on Bt formulations

• Make certain you are obtaining the correct
  formulation for the task.
• Bti var. israelensis for Diptera immature
  flies, primarily mosquitoes. (Mosquito Dunks).
• May also have some effect on other fly species.
• Cost 6 pack of dunks17.95
• 40 lb granular150

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Brief Lesson on Bt formulations

• Make certain you are obtaining the correct
  formulation for the task.
• Btt var. tenebrionis or san diego for
  Coleoptera larvae immature beetles.
• Marketed for elm leaf beetles, Colorado potato
  beetle and may work on others.

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Brief Lesson on Bt formulations

• Make certain you are obtaining the correct
  formulation for the task.
• Bp Bacillus popillae (Milky spore) for Japanese
  beetle larvae.
• Not generally effective on annual white grubs or
  other scarab beetles.
• Cost 40 oz. 80

31
Drawing a distinction between Farming vs.
Gardening

• Many organic strategies are more applicable on a
  small scale (home garden) but may not be
  practical or affordable in large acreage
  situations (farming).
• Organic strategies involve a personal commitment
  to doing things differently for the preservation
  of the ecosystem for the next generation.
• Organic strategies generally require more money,
  time and dedication to detail than conventional
  methods, therefore, for the farmer, there must be
  an economic benefit.
• IPM practitioners are always looking for
  compromises that incorporate organic alternatives
  and more eco-friendly materials into the arsenal
  of tools available to the farmer. These
  compromises (often unacceptable as organic),
  represent safe, eco-friendly and more
  economically sound approaches to pest management.
• May incorporate insect growth regulators and
  other highly specific insecticides not certified
  as organic.

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List of Resources for Organic Growers

• Handout with various website and handbook
  resources from general information to insect
  guides, and insect, weed and disease management.
• Several organics catalogs available (e.g.
  Arbico organics).
• Several resources for IPM practitioners, which
  utilize several possible mechanisms for managing
  pests below economically established thresholds
  (e.g. Great Lakes IPM).
• Excellent tutorial with detailed information on
  much of this presentation is available through
  the North Central Regional Extension Publication
  401, Alternatives in Insect Management
  Biological and Biorational Approaches by Rick
  Weinzierl and Tess Henn Available on-line at
  http//www.aces.uiuc.edu/vista/abstracts/aaltinsec
  .html