Nursery IPM for Insect Control

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Nursery IPM for Insect Control

• K.V. Tindall
• University of Idaho
• Twin Falls, ID

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Insect Control for Nurseries

• Difficult situation for insect control
• Physical conditions of greenhouses
• Absence of natural enemies
• Few insecticides for nursery plants
• Scout for problems and keep records
• Take action when necessary
• Watch for trends
• Can aid in variety selection

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Management Techniques

• Integrated Pest Management (IPM)
• Management of pests that incorporates many
  practices for environmentally friendly and
  economically feasible control of pests
• Physical/Mechanical screens, squashing
• Cultural plant varieties, plant health
• Biological arthropods, pathogens, nematodes
• Chemical larvicides vs adulticides, deterrents

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Physical and Mechanical Control
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Greenhouse Screens

• Calculate volume of greenhouse
• Select mesh size of screen for target pest
• Determine the approach velocity
• Divide greenhouse volume by approach velocity
  required area of screen
• Divide the required area of screen by the length
  of the house the screen area required per foot
  of building

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Greenhouse Screens

• 100' x 100' house w/ a 10' eave height 100,000
  ft3
• Select mesh size for the target pest 52 mesh

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Greenhouse Screens

• 100' x 100' house w/ a 10' eave height 100,000
  ft3
• Select mesh size for the target pest - 52 mesh
• Determine the approach velocity - 52 mesh 264

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Greenhouse Screens

• 100' x 100' house w/ a 10' eave height 100,000
  ft3
• Select mesh size for the target pest - 52 mesh
• Determine the approach velocity - 52 mesh 264
• Required area of screen greenhouse volume /
  approach velocity - 100,000 264 380 ft2
• Required screen area per foot of building
  required area of screen / length of house - 380
  100 3.8 ft2 per foot - almost 4 ft2 per ft
• Smaller approach velocity tighter screen
  greater the area of screen required for adequate
  airflow

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Monitor Sticky Traps

• Build or purchase (8 ½ X 12)
• Bright yellow on both sides
• Warning Yellow or Safety Yellow
• Attractive to aphids, whiteflies, leafminers,
  leafhoppers, thrips
• Blue and white but yellow is best
• Traps covered with a nondrying sticky material
  (commercial insect adhesives)
• Cleaned/replaced if dusty or high insect
  populations

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Monitor Sticky Traps

• Hang 10-12" above crop canopy
• At least one trap for every 1,000 sq ft of floor
  space
• BUT the more the better
• Place near all doors vents to detect entry
• Traps should not be visible from outdoors

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Monitor Non-Greenhouse

• Small diverse blocks of plants containers
• Make a map, walk across field
• Examine 10 plants of each variety
• Record problem determine infested
• Rate severity of infested plants
• Mark 3-5 infested plants with flag
• Indicator plants
• Monitor spread and treatment efficacy

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Monitor Non-Greenhouse

• Large uniform blocks of single plant type
• Large uniform blocks (gt1 acre, or gt1000 pots)
  different techniques
• Scout 3 widely spaced locations
• Examine 10 plants at each location
• Indicator plants for each problem
• Monitor plants for insect populations

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Insect Cages
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Cultural Control
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Healthy Plants Best Defense

• Usually able to withstand insect damage
• Avoid stressed plants
• Water
• Light
• Nutrients
• Competition
• Disease
• Some insects prefer stressed plants

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Plant Defenses Variety Selection

• Three ways plants are resistant
• Tolerance
• Plants able to withstand injury better
• Antixenosis
• Not-preferred
• Too hairy, too waxy
• Odorous
• Antibiosis
• Toxic to the insect
• Plant compounds with in the plant

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Trap Crops

• Highly attractive plant
• May have cash value - may not
• Attracts insects early
• Manage insects in trap crop before they move to
  plant of interest

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Trap Crops

• Highly attractive plant
• May have cash value - may not
• Attracts insects early
• Manage insects in trap crop before they move to
  plant of interest

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Biological Control
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Whiteflies

• Parasitic wasp, Encarsia formosa
• Lays eggs in whitefly nymphs
• Larvae feed on the nymphs WF death
• Introduce into greenhouse when low populations
• Too late unsuccessful control
• Up to 3,000 pupae per 1000 m2 of plant area
  evenly distributed
• Temperatures requirements gt70o to outbreed the
  whitefly

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Whiteflies

• Safers insecticidal soap concentrate - rate of 1
  part per 100 parts of soft water ( 0.05
  solution)
• Can be used in combination with parasites

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Spider Mites

• Outbreaks often occur with localized infestations
• bronzing of leaves, webbing, etc.
• Several predacious mites are available
• Phytosielus persimilis attack red mites
• P. punctum and Amblyseius fallacis attack both
  red and two-spotted spider mites
• Introduce when populations are low
• Less effective at high temps

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Leafminers

• Natural parasites may enter
• May establish if insecticide applications are
  stopped
• Questionable efficacy w/o continual or
  supplemental release
• Parasitic flies commercially available
• Diglyphus isaea and Dacnusa sibirica (Minex)

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Aphids

• Many biological controls
• Naturally occurring soil fungi
• Verticillium lecanii (Vertalec)
• Metarhizium anisopliae (Bioblast or BioPath)
• Predatory gallmidges
• Aphidoletes aphidimyza (Aphex)
• Deposit eggs near aphids
• Larvae emerge, paralyze, feed on, and kill
  aphids
• Pupate in the soil
• Releases must occur when populations are low

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Aphids

• Ladybugs - general feeders
• Green brown lacewing
• Put out eggs, larvae emerge
• General feeders on soft-bodied insects
• 1,000 lacewing eggs per 200 ft2 of greenhouse
  space

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Aphids

• Several species of Brachonids
• Lays egg in an aphid
• Larva feed inside aphid and emerge from the body
  as an adult
• Healthy Brachonid population dry, brown aphid
  bodies with a circular hole cut in their back
• Applications of chemical insecticides are harmful

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Thrips

• Parasitic wasp,
• Thripobius semiluteus
• Several predacious mites
• Amblyseius cucumeris Hypoaspis spp.
• Each adult mite eats 2-3 thrips per day
• Female mites lay 3 eggs/day

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Mealybugs

• Ladybug
• Cryptolaemus montrouzieri
• Feeds heavily on mealybugs and some scales
• Chalcid wasps
• Leptomastix dactylopii, Leptomastidea abnormis,
• Attack large nymphs female adults
• 200 or more eggs/day in mealybug
• Larvae feed inside leaving a mummy
• Release 2-5 wasps per 1m2 of plant area at least
  twice per year

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Fungus Gnats

• Fungus gnats are more fragile looking, have
  longer legs, dark wings, and a funguslike body
  covering.

• Shore flies can be distinguished by their compact
  bodies, short legs, and short antennae

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Fungus Gnats

• 1st defense cleanliness in and out of the
  greenhouse
• Eliminate rotting nearby vegetation
• Clean wet areas that support growth of algae
• Bacillus thuringiensis israelensis (Gnatrol)
• Water necessary to get it to insects
• Larvae stop feeding within 24 hrs
• Not effective against adults
• Should not be mixed with fertilizer or fungicides
  containing copper or chlorine

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Fungus Gnats

• Predacious mites
• Hypoaspis spp.
• For early control of fungus gnats
• 3-4 weeks to see reduction
• Beneficial nematodes
• Steinernema carpocapsae and Hetero-rhabditis
  bacteriophora, (BioSafe, Exhibit)
• Apply directly to the soil (water)
• Work well in moist soils (50-85oF)
• One box covers 225-250 ft2

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Tips for Release of Natural Enemies

• Dont leave in a hot vehicle or in the sun
• Dont apply during the hottest part of the day
• Apply when pest is present but before the pest
  population gets out of hand
• 2nd app. 2 wks after the 1st - newly hatched eggs
• Different predatory mites require different
  levels of humidity.
• Consult labels or instructions prior to use
• Results may not be seen for 1-3 weeks
• Dont assume it didnt work and spray

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Chemical Control
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Compatibility with Beneficial Insects

• Azatin EC (azadirachtin)
• natural insect growth regulator made from neem
  tree
• Insecticidal Soap (Safers, Biopax, M-pede,
  Naturell)
• Contact insecticide from biodegradable fatty
  acids
• Can be mixed with other pesticides
• Kinoprene (Altodel, Enstar, and Enstar II)
• organic compound used an as insect growth
  regulator

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Compatibility with Beneficial Insects

• Rotenone
• Botanical insecticide
• Broad spectrum, kills most predators parasites
• Pyrethrum
• Botanical insecticide
• Broad spectrum - toxic to most predators
  parasites
• Bacillus thuringiensis, or Bts
• Bacterial insecticides that attack certain pests
• Safe to predators, parasites
• Active on immature NOT adults

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General Insecticide Info

• Always read and follow the label for specific
  instructions for all insecticides.
• Never use insecticide for uses other than on the
  label.

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