Organic Pest Management

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Organic Pest Management

• Debbie Roos
• North Carolina Cooperative Extension

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Outline

• Organic Pest Management Philosophy
• Insect Management
• Gallery of Beneficial Insects
• Gallery of Pest Insects
• Pest Management Resources

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Organic Pest Management Philosophy
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Appropriate Technology
Organic?
Conventional?
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Organic Pest Management Approach

• pests are indicators of how far a production
  system has strayed from the natural ecosystems it
  should imitate
• insect pests are attracted to a plant that is
  weak or inferior
• in a well-balanced system, massive pest outbreaks
  are rare due to the presence of natural
  predators, parasites, and disease agents

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Organic Pest Management Approach

• prophylactic, holistic approach vs. remedial
  approach
• not just treating symptoms
• pest problem usually indicates sub-optimal
  growing conditions and imbalance
• emphasis on biodiversity and optimal cultural
  practices

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Organic Pest Management Example

• Conventional approach spray insecticide to
  control caterpillars, which often results in a
  secondary outbreak of aphids or spider mites
  because beneficial insects such as lady beetles
  and other predators are also killed
• Organic approach enhance habitat for beneficial
  insects to increase population, reduce stress on
  crop plant, use adapted varieties, and use
  non-chemical methods to control pests (Bt,
  hand-picking, row covers, alternating planting
  dates, traps, etc.)

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Cultural Controls
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Cultural Controls

• Resistant cultivars
• Crop rotation
• Companion planting
• Timing of planting
• Sanitation
• Soil Management

• Mulches
• Composting
• Tillage
• Flaming
• Trap crops

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Resistant Cultivars

• Some varieties may be less attractive to pest
  species or tolerate more damage than others
• Plant size, shape, coloration, leaf hair, cuticle
  thickness, and natural chemicals (attractants and
  repellents) can all affect pest susceptibility

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Resistant Cultivars

• Morphological characteristics include those plant
  structures that interfere with insect movement,
  feeding, or reproduction associated with that
  plant
• Examples include color, thickness of the cell
  walls and plant tissue, surface wax, spines and
  trichomes

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Resistant Cultivars

• Physiological defenses include plant-produced
  compounds that deter certain pests e.g.,
  pyrethrum, is derived from the blooms of an
  African chrysanthemum
• Some plants have specific color-related
  resistance
• Most insects are attracted to leaves in the
  yellow-green color range. Healthy, dark green
  leaves are less attractive than yellowing plants
  under stress.

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Crop Rotation

• insects overwinter in soil and debris, reinfest
  new crop if susceptible and build up populations
• 3 questions to consider when deciding whether
  crop rotation will help manage a pest
• How long can the pest persist in the field
  without any host
• How capable is it of invading from other areas
• How well does it survive on other hosts when the
  crop is not present
• plant non-susceptible crop so pests have no food
• know your botanical families leave as much time
  as possible between related crops

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Companion Planting

• attractant crops - small-flowered - carrot
  family, daisy family, mint family - catnip,
  caraway, dill, fennel, hyssop, lemon balm,
  parsley, rosemary, thyme, yarrow, etc.
• repellent crops - catnip and tansy repel aphids,
  Artemesia repels flea beetles???
• Lots of recommendations out there with little
  scientific evidence need more study before
  recommending some companion plants increase pest
  populations

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Timing of Planting

• keep notes to record pest and disease outbreak
  patterns - the first date you see a problem and
  the coinciding phenological events
• adjust planting schedule accordingly to avoid
  peak pressure
• experiment with different planting dates - e.g.,
  to avoid corn earworm or flea beetle or squash
  bug
• plant crops susceptible to nematodes early or
  late while soil temperatures are cooler

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Sanitation

• select healthy plants
• rogue and prune
• remove crop debris promptly to reduce
  overwintering sites for pests
• eliminate alternate hosts, but be careful about
  timing

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Soil Management

• Healthy soils high in OM and with a biologically
  diverse food web support plant health and
  nutrition better than soils low in organic matter
  and species diversity. Healthy plants are
  generally less susceptible to pest damage.
• Approximately 75 of insect pests spend part of
  their life cycle in the soil. Healthy soils
  contain many natural enemies of insect pests,
  including insect predators, pathogenic fungi, and
  insect-parasitic nematodes.

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Soil Management

• A soils physical condition its level of
  compaction, water-holding capacity, and drainage
  all affect soil and plant health.
• The chemical aspects of soils pH, salt content,
  availability of nutrients, etc. can affect crop
  health and pest susceptibility.

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Strategies for Improving Soil Health

• Increase soil organic matter
• Keep soils covered with cover crops and/or crop
  residue to reduce erosion and protect from
  extremes of moisture and temperature
• Plan tillage operations carefully

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See Example of Seedcorn Maggotson Growing Small
Farms Website
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Mulches

• Plastic mulches that speed early season crop
  growth can enhance plants ability to withstand
  insect feeding
• Reflective mulches can reduce thrips and aphid
  populations in crops
• Straw mulch can reduce problems with Colorado
  potato beetle

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Tillage

• disrupts life cycle of pests and beneficials
• can expose pests to predators, the elements
• till before planting to control weeds that harbor
  armyworms, cutworms, plant bugs, aphids
• till in the fall to destroy overwintering sites
  for flea beetles, corn borers, squash bugs, etc.
• balance with need to maintain groundcover

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Flaming

• Technique aimed at overwintering Colorado potato
  beetle
• Propane burners used to quickly pass a flame over
  young potato plants when beetles are on top
• Does little harm to the crop when the plants are
  less than 4-5 tall

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Trap Crops

• A trap crop is a crop that is planted to lure
  insect pests away from the cash crop.
• Successful use of trap crops can be challenging.
  The trap crop must be more attractive to the pest
  than the cash crop, and care must be given that
  the pests in the trap crop dont later migrate to
  the cash crop. Trap crops are not effective
  against pests that are weak fliers (e.g., aphids)
  or are wind-dispersed (e.g., spider mites).
• In organic systems with fewer insecticidal
  options, pests are often killed through crop
  destruction. But the timing of crop destruction
  is critical
• Research on trap crops has revealed mixed results
  for its use as a pest management strategy.
• Example from NC SARE producer grant in mountains
  trap crops in organic broccoli

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Trap Crop in Organic Broccoli
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Physical Controls
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Physical Controls

• Manual controls
• Physical barriers
• Baits, traps, and lures

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Manual Controls

• Hand-picking
• Mowing
• Pruning
• Shaking
• Water sprays

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Physical Barriers

• Bagging fruit
• Copper strips
• Crawling pest barriers
• Cutworm collars
• Floating row covers
• Mulches
• Trenches
• Trunk bands

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Baits, Traps, and Lures

• Bait traps
• Japanese beetle traps
• Pheromone traps
• Slug and snail traps
• Sticky boards
• Trap crops
• Water traps

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Biological Controls
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Biological Controls

• Beneficial animals and insects
• Beneficial microorganisms - Bt, milky spore,
  Beauveria bassiana (fungus), Nosema (protozoan)

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Biological Control in Action

• Augmentation increase population through
  purchase and release
• Conservation increase existing populations
  through habitat conservation and other means

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Organic PesticidesRescue Treatments
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Pesticides in Organic Production

• When cultural, mechanical, and biological
  strategies are insufficient to prevent or control
  crop pests, weeds, or diseases, a biological or
  botanical substance or a substance included on
  the National List of synthetic substances allowed
  for use in organic crop production may be applied
  to prevent, suppress, or control pests, weeds, or
  diseases
• The conditions for using the substance must be
  documented in the organic system plan

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Pesticides in Organic Production

• If certified organic, must choose pesticide that
  is approved for organic production
• consult with certifying agency
• also consult OMRI

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Botanical Pesticides

• Plant-derived materials such as neem, pyrethrum,
  rotenone, ryannia, and sabadilla
• Characteristics of botanical insecticides
• break down rapidly in the environment
• some are more toxic than synthetic pesticides
• broad spectrum
• must be used carefully
• only neem and pyrethrum are approved for organic
  production

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Pyrethrum

• extracted from a flower in the chrysanthemum
  family
• a contact poison with quick knock down
• controls aphids, beetles, caterpillars, thrips,
  mealybugs
• OMRI-approved products include Pyganic

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Neem (azadirachtin)

• extracted from the fruit of a tree grown from
  India to Africa
• works as a hormone mimic, repellant, stomach
  poison and some fungicidal properties have been
  reported
• controls a wide variety of insects
• OMRI-approved formulations include AZA-Direct,
  Agroneem, Neemix

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Microbial Pesticides

• Microbials tend to not be as toxic as botanicals
  and are more selective and softer on beneficials
• Limitations of microbials
• Slow host death
• Need favorable environment
• UV light and temperature affect persistance
• Bacillus thuringiensis (Bt)
• parasitic fungi - e.g., Beauveria bassiana
• parasitic nematodes e.g., Heterorhabditis
• Spinosad

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Bacillus thuringiensis (Bt)

• contains a toxin made by a soil bacterium
• has been incorporated into commercial plants to
  make them insecticidal (not allowed in organic
  production)
• sprayed formulations sensitive to UV light best
  applied late in the day
• must be ingested to work
• Several OMRI-approved formulations

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Parasitic Fungi

• e.g., Beauveria bassiana
• The spores of the fungus germinate once they come
  into contact with the insect pest, then the
  fungus must penetrate the cuticle and infect the
  body cavity to kill the pest
• Effective on many insects including aphids,
  thrips, whiteflies, and grasshoppers
• Work best when applied at onset of infestation
• Takes a week or more after application to see
  evidence of control
• OMRI-approved formulations include Mycotrol,
  Naturalis L

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Parasitic Nematodes

• semi-aquatic live and move in soil water
• sensitive to UV radiation and desiccation
• Heterorhabditis (Hb) vs. Steinernema (Sc)
  nematodes
• application - spray or irrigation drip,
  fertigation aerial, watering can application
  should be followed by irrigation dont apply
  during hottest part of day but soils should be
  gt60º

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Spinosad

• Derived from a soil-dwelling bacterium
• Controls beetle larvae, caterpillars, thrips,
  etc.
• Most effective when ingested rather than as a
  contact insecticide
• Fast-acting, better than Bt on caterpillars
  supposedly not as soft on beneficials so use in
  targeted areas
• Entrust - Formulation approved for organic
  production in many vegetables

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Inorganic Pesticides

• Diatomaceous earth
• Kaolin
• Insecticidal soap
• Horticultural oil

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Okay, Now Its Time to Look at Some Insects, so
First, A Little Entomology 101
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Insect Classification

• Kingdom - Animalia
• Phylum - Arthopoda
• Class - Insecta
• Order - Coleoptera
• Family - Coccinellidae
• Genus - Coleomegilla
• Species - maculata

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Some Insect Orders

• Coleoptera beetles
• Diptera flies
• Homoptera aphids, scales, whiteflies
• Hymenoptera bees, wasps, ants
• Hemiptera - bugs
• Lepidoptera butterflies, moths
• Neuroptera lacewings, antlions

• Mantodea praying mantis
• Odonata dragonfly, damselfly
• Orthoptera crickets, grasshoppers
• Thysanoptera thrips
• Isoptera termites
• Siphonoptera fleas
• Dermaptera earwigs

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Structure of a Typical Insect
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Insect Features
Wings
Antennae
Mouthparts
Legs
Ovipositors
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Insect Development Metamorphosis

• Complete
• Metamorphosis
• 4 distinct stages egg, larva, pupa, adult
• Examples beetles, butterflies, flies, wasps,
  lacewings, fleas
• Incomplete
• Metamorphosis
• 3 stages egg, nymph, adult
• Examples bugs, aphids, thrips, grasshoppers,
  termites, earwigs

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Gallery of Some Common Beneficial Insects
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What are Natural Enemies?

• Organisms that kill, decrease reproductive
  potential, or otherwise reduce the numbers of
  another organism
• How do they do this? Through predation,
  parasitism, herbivory, competition, antibiosis
  (when organisms secrete substances that inhibit
  vital activities of other organisms)

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Beneficial Organisms

• Predators larva or adult hunts, attacks, and
  consumes prey examples include lady beetles,
  lacewings, praying mantids, syrphid flies,
  assassin bugs, minute pirate bugs, spiders, and
  predatory mites
• Each one eats many insects in its lifetime
• Not picky eaters

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Beneficial Organisms

• Parasitoids immatures develop on or inside a
  host, killing it as they mature they emerge as
  adults and continue the cycle examples include
  parasitic flies and wasps
• Each one eats only one insect in its lifetime
• Usually very picky eaters

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Beneficial Organisms

• Pathogens colonize and kill host examples
  include nematodes, bacteria, viruses, fungi and
  protozoa
• Weed Feeders weeds can be attacked by
  arthropods, vertebrates, and pathogens (fungi,
  viruses, bacteria, and nematodes)

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BeetlesOrder Coleoptera
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Beetles

• 1/3 of all animals 40 of all insects are
  beetles
• Hard opaque wing covers are called elytra
• Beetles undergo complete metamorphosis
• Larvae and adults have chewing mouthparts
• Larvae have well-developed heads and 3 pairs of
  legs

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Lady BeetlesOrder ColeopteraFamily
Coccinellidae
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Lady Beetles

• Larvae and adults eat
  soft-bodied insects such as aphids, mealybugs,
  spider mites, caterpillars, insect eggs
• Voracious aphid feeders!
• Two main body types
• Round (hemispherical)
• Oval

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Round Lady Beetles
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Seven-spotted Lady Beetle
2 white spots on thorax
7 spots in a 1-4-2 pattern
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Seven-spotted lady beetle lunches at the aphid
café
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Seven-spotted lady beetle larvae like aphids
too!
Larvae hatching
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Multicolored Asian Lady Beetle
Black spots form M
larva pupa
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Oval Lady Beetles
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Convergent Lady Beetle
Thorax has two converging white lines and a white
margin
larva and eggs
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Pink Spotted Lady Beetle
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Plant-feeding Lady Beetles
Squash beetle
Mexican bean beetle
larvae and pupa
parasitized mummy
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Other Predatory Beetles Order Coleoptera
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Ground Beetle
Larvae and adults attack aphids, slugs, snails,
cutworms, caterpillars nocturnal foragers
larva feeding on caterpillar
adult
adult feeding on snail
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Rove Beetle
Adults attack aphids, nematodes, flies some
larvae are parasitic on maggots
short elytra
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Soldier Beetle
Adults feed on grasshopper eggs, aphids, and
various caterpillars larvae feed on a variety of
insects and snails and slugs
dead fungus-infected soldier beetle
look-alike lightning bug
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Tiger Beetle
Adults attack many different insects
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Blister Beetle
Larvae feed on grasshopper eggs, adults feed on
foliage and fruits
striped blister beetle
margined blister beetle
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True BugsOrder Hemiptera
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True Bugs

• Two pairs of wings usually present
• Forewings modified to hemelytra, hindwings
  entirely membranous
• Mouthparts enclosed in a piercing-sucking beak
  that curves beneath the body
• Incomplete metamorphosis egg, nymph, adult
• Some groups (e.g., stink bugs) have scent glands
  on the sides of thorax
• Order includes both plant feeders and predators

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Predatory BugsOrder Hemiptera
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Minute Pirate Bug
adult feeding on egg
Adults and nymphs attack aphids, mites, thrips,
small caterpillars, and insect eggs
adult feeding on aphid
nymph
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Bigeyed Bug
adult
Adults and nymphs attack mites, thrips, flea
beetles, small caterpillars, and insect eggs
egg
nymphs
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Bigeyed Bug Look-Alikes
Boxelder Bug
Bigeyed Bug
Tarnished Plant Bug
Pestsmall head and eyesbright coloration
Pestsmall head and eyesdull coloration
Beneficialwide head, big eyesdull brown or
black
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Damsel Bug
Adults attack aphids, thrips, leafhoppers, flea
beetles, plant bugs, and small caterpillars
Adult (left) and nymph
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Assassin Bug
adult
eggs
Adults and nymphs attack many insects, including
flies, tomato hornworms, and other large
caterpillars
nymph
adults attacking caterpillar
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Bee Assassin
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Assassin Bug Look-Alike
Leaf-footed bug
Assassin bug
Pestleaf shape on back legthin, hidden beak
Beneficiallong, thin, unadorned legsshort,
thick, curved beak
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Assassin Bug Molting
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Predatory Stink BugsFamily Pentatomidae
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Spined Soldier Bug
Adults and nymphs attack caterpillars, Colorado
potato beetle larvae, Mexican bean beetle larvae
Podisus adult attacking beetle larva
nymph attacking Colorado potato beetle larva
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Other Predatory Stink Bugs
Twospotted stink bug (Perillus bioculatus)
Anchor bug (Stiretrus anchorago)
Anchor bug feeding on asparagus beetle larva
nymph
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Pest and Beneficial Stink Bugs
beak structures of predaceous (left) and
plant-feeding (right) stink bugs
beak structure of brown stink bug and spined
soldier bug
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LacewingsOrder Neuroptera
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Green Lacewing
larva feeding on aphids
larva
Larvae attack soft-bodied insects including
aphids, thrips, mealybugs, scales, mites, and
caterpillars
larvae emerging from eggs
stalked eggs
adult
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Brown Lacewing
larva
adult
egg
pupa
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Other Predators
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Parasitic WaspsOrder Hymenoptera
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Parasitic Wasps

• Hymenoptera is the second largest group of
  insects
• Over 16,000 species, most of which are
  beneficial, are found in the U.S. and Canada
• Many parasitic wasps are so tiny that many new
  species are discovered each year!
• They range in size from over an inch to almost
  microscopic
• Parasitic wasps are the most important group of
  natural enemies of pest insects
• All Hymenoptera undergo complete metamorphosis

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Parasitic Wasps

• In parasitic wasps, the larval stage develops in
  and kills a single host insect most adults have
  a very high reproductive capacity, which makes
  them efficient at suppressing pests
• The behavior of parasitic wasps is quite complex
  many attack only one species of host insect, or
  a narrow range of similar hosts
• Adult females are very efficient at locating the
  specific hosts
• Hosts include almost all groups of terrestrial
  insects
• Depending on the parasite species, virtually any
  host stage can be attacked egg, nymph, larva,
  pupa, adult
• Most parasitic wasps are incapable of stinging
  humans

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Braconid Wasps
Parasitize armyworms, cabbageworms, codling
moths, gypsy moths, European corn borers, beetle
larvae, flies, aphids, and other caterpillars and
insects
Braconid parasitizing a corn earworm
mummy of an aphid parasitized by Braconid wasp
Aphidius
Braconid larvae emerging from parasitized moth
larva
Braconid pupae on tomato hornworm
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Ichneumonid Wasps
Parasitize caterpillars, wasps, and beetle larvae
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Scelionid Wasps
adult ovipositing in a stink bug egg cluster
Parasitize eggs of
caterpillars and bugs
parasitized stink bug eggs
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Encyrtid Wasps
Encarsia formosa parasitizes greenhouse whiteflies
Parasitize eggs, larvae, and pupae of aphids,
scale, beetles, caterpillars, and whiteflies
whitefly nymphs (black ones have been parasitized)
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Encyrtid Wasp (Copidosoma floridanum)
adult parasitizing a cabbage looper egg
Parasitize eggs of
caterpillars polyembryonic
adults emerging from a mummified cabbage looper
host
looper parasitized by Copidosoma curls into
S-shape after spinning its coccoon
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Trichogramma Wasp
adult parasitizing a moth egg
Parasitize eggs of many pests, especially moths
and butterflies
commercial Trichogramma wasps are shipped as
parasitized moth eggs glued to a card note
emerged adult near pencil point
parasitized eggs are darker
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Parasitic FliesOrder Diptera
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Parasitic Flies

• Flies are second only to the Hymenoptera in their
  importance as parasites
• An estimated 16,000 species of flies are
  parasitic, about 20 of all known parasitic
  insects
• Unlike parasitic wasps, most species of flies do
  not have a well-developed ovipositor that can
  insert eggs into their host many parasitic flies
  lay their eggs on plants which are then consumed
  by the host

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Tachinid Fly
Parasitize cutworms, caterpillars, Japanese
beetle, squash bug, green stink bugs,
grasshoppers, and other pests
adult approaching a beetle larva
eggs deposited on top of Japanese beetle and tent
caterpillar heads
Tachinid larva emerging from caterpillar
adult laying an egg
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Predatory FliesOrder Diptera
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Predatory Flies

• At least 20 fly families have species that are
  predaceous as larvae or adults
• In species with predaceous larvae, adults lay
  their eggs singly or in scattered groups on
  plants near colonies of mites or aphids

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Hover Fly
adult
Larvae attack aphids, scales, and other insects
hover fly larvae feeding on aphids
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Robber Fly
Adults and larvae attack a variety of
soft-bodied insects
adult
Aphid Midge
Larvae attack aphids
midge larva feeding on aphid
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Long Legged Fly
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The Fabulous Underworld
of a Tomato Canopy
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PestsSee Photos on GSF Website at
http//chatham.ces.ncsu.edu/growingsmallfarms/i
nsects.html
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Growing Small Farms Website

• Organic Pest Management
• Other Resources

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Other Resources(see handout)