Economic Thresholds

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EconomicThresholdsIPMStrategy

• Dewey M. Caron
• University of Delaware

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IPM Integrated Pest Management
IINTEGRATED ideally use of more than pesticide
chemical control PPEST mites sure but
applicable to any of the 3 Ps MMANAGEMENT as
you mange the bee population you manage the Ps

• Several techniques are employed
  simultaneously to solve specific pest
  problems

Alternative BMPs Best Management Practices
names Alternative Treatments (non-pesticide)
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IPM

• IPM is a decision-making process for control of
  PESTS
• PEST pathogens, parasites, predators of honey
  bees, their colonies /or products
• Bee Mites have changed the face of beekeeping
  no longer bee-havers
• We are management specialists!

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Four Fundamental Strategies for Pest Management

• Do nothing
• Reduce numbers of pest
• Reduce susceptibility of the host
• Use combinations of the last two

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Goals to Focus on When Developing a Pest
Management Plan

• Reduce pest status
• Conserve environmental quality
• Accept tolerable pest densities
• Improve net profits
• TimingNOT calendar treatments

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Implementation of Pest Management Strategies

• Pest identification
• Pest population assessment
• Economic evaluation
• Timing of controls
• Is economic damage possible/imminent?

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How to Achieve These Goals

• Efficient sampling methods
• Valid decision guidelines
• Integrating a number of effective tactics for an
  overall plan of attack
• Acceptance of higher mite levels

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IPM in Practice

• MONITORING
• Mite levels fluctuate within between seasons.
  We must carefully sample (scout or monitor)
• and then use best estimates to determine risk
  level if risk elevated we control!
• We MUST
• - Understand bee/mite life cycle
• - be able to ID mite predict

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Varroa mite a pest or vector?
K-Wing or Wingless bees of value?
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Adult female mite enters larval cell as
it completes development. She hides on side
wall as pre-pupa spins cocoon
Illustration series from Martin IN Mites of
Honey Bees Dadant Sons, Inc 2001
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In 60 hours she lays 1st egg (male). After 24
hours she lays female egg one every 24 hours
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Her son (male) develops feeding on pupa
mates w/ sister as she matures
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When adult bee emerges 1.3 adult female mites are
mature if eggs on drone 3X are mature
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SOLUTION?
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Control Collapse w/ Pesticides
Resistant mites increase with each generation
Due to (1)selection pressure (2)Sub-optimal
exposure
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Economic Threshold
80
Avoid exceeding economic injury level
70
EIL
60
Apply controls
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Pest density
ET
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Averagedensity
30
20
10
0
Time
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Mite Numbers
Increase seasonally
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Mite Numbers
High mite yr
Low mite yr
Vary between colonies years
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Monitoring

• On brood
• - worker
• - drone
• On bees
• - ether roll
• - powdered sugar
• - alcohol wash
• In colony
• - Sticky board

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IPM THRESHOLDMonitoring can supply a
number - a guesstimateOne or more
numbers can be obtained - use number(s) to
evaluate mite population- one mite in sample X
mites in colony(150 in U.S. -- 1100
Europe)Determine an appropriate risk level-
one mite vs 100 vs 1000?Assumption 3000 mites
in fall represents a minimally acceptable
conservative risk??? Balance of costs vs
benefits
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Valadation of mite sample bars to actual
numbers background Not perfect but good
correlation
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Threshold

• An acceptable level of pests mites determine
  necessity of further controls
• A number to use to evaluate mite control efficacy
  efforts
• Allows estimation of risk if no pesticide
  chemical is integrated into the control
• The basis for IPM a decision process utilizing
  modern pest control practices

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Threshold

• Spring/summer (April or May or Mid-June)
• Sticky boards over 5-10
• Adult bees over 3-4
• Brood over 5
• Exceeding threshold means additional control may
  be useful
• Pre-fall (mid-August, Sept too late!)
• Sticky boards over 50-60 means additional
  control
• Adult bees over 10-12
• Brood over 5-10
• Exceeding threshold means additional (chemical)
• control needed

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IPM Mite Control Triangle
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Varroa Mites cultural control

• Apiary site location
• Comb culling
• Small-sized cell base
• Requeening w/ Resistant (tolerant) stock
• Hygienic queen stock
• SMR (surpressed mite resistance)
• Russian stock

From Martin In Mites of the Honey Bee
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Varroa Mites physical control

• Screened bottom boards (season long)
• Drone brood trapping (1X to 8X)
• Heat (104-110?F for 4 hrs)

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Varroa Mites physical control
Screened bottom board
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Varroa Mites biological control

• No identified control agent so far
• Best choice seems to be a virus or fungus

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Varroa Mites Chemical control

• Miticides - Apistan Checkmite Amitraz
• Formic acid - Apicure Mite-Away II
• Other acids (acetic oxalic)
• Essential oils
• Thymol Api Life VAR thymol others ApiGuard
  
• Others -thyme, citronella, clove, camphor,
  eucalyptol
• Semiochemcials Nasanov gland pheromones
  others
• Mineral/vegetable oil (FGMO), esters
• Grease patties oil machines, Sucrocide
• Drying agents
• Diatomaceous earth, talc, powdered sugar

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Varroa Mites - Chemical Control

• Pesticides natural/synthetic need to be
  approved (registered) for legal use
• Emergency registration (i.e. Checkmite) means
  emergency temporary answer
• Natural doesnt mean less toxic
• DUMB chemicals (less toxic, not pre-packaged)
  need SMART beekeepers

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