EconomicEconomicThresholdsThresholds

&&IPMIPM

StrategyStrategy

Dewey M. CaronDewey M. CaronUniversity of DelawareUniversity of Delaware

IPM – Integrated Pest IPM – Integrated Pest ManagementManagement

““Several techniques are employed Several techniques are employed simultaneously to solve simultaneously to solve

specific pest problems”specific pest problems”

I=INTEGRATED – ideally use of more than pesticide I=INTEGRATED – ideally use of more than pesticide chemical controlchemical control

P=PEST – mites sure but applicable to any of the 3 P’sP=PEST – mites sure but applicable to any of the 3 P’s

M=MANAGEMENT – as you mange the bee population M=MANAGEMENT – as you mange the bee population you manage the P’syou manage the P’s

Alternative BMP’s Best Management Practices names: Alternative Treatments (non-pesticide)

IPMIPMIPM is a decision-making process for IPM is a decision-making process for control of PESTScontrol of PESTS

PEST = pathogens, parasites, predators of PEST = pathogens, parasites, predators of honey bees, their colonies &/or productshoney bees, their colonies &/or products

Bee Mites have changed the face of Bee Mites have changed the face of beekeeping – no longer bee-haversbeekeeping – no longer bee-havers

We are management specialists!We are management specialists!

Four Fundamental Four Fundamental Strategies for Pest Strategies for Pest

ManagementManagementDo nothingDo nothingReduce numbers of pestReduce numbers of pestReduce susceptibility of the hostReduce susceptibility of the hostUse combinations of the last twoUse combinations of the last two

Goals to Focus on Goals to Focus on When Developing a When Developing a

Pest Management PlanPest Management Plan

Reduce pest statusReduce pest statusConserve environmental qualityConserve environmental qualityAccept tolerable pest densitiesAccept tolerable pest densitiesImprove net profitsImprove net profitsTiming…NOT calendar treatmentsTiming…NOT calendar treatments

Implementation of Pest Implementation of Pest Management StrategiesManagement Strategies

Pest identificationPest identificationPest population assessmentPest population assessmentEconomic evaluationEconomic evaluation**

Timing of controlsTiming of controls

* Is economic damage possible/imminent?* Is economic damage possible/imminent?

How to Achieve These How to Achieve These GoalsGoals

Efficient sampling methodsEfficient sampling methodsValid decision guidelinesValid decision guidelinesIntegrating a number of effective Integrating a number of effective tactics for an overall plan of tactics for an overall plan of attackattackAcceptance of higher mite levelsAcceptance of higher mite levels

IPM in PracticeIPM in PracticeMONITORINGMONITORINGMite levels fluctuate within & between Mite levels fluctuate within & between seasons. We must carefully sample seasons. We must carefully sample (=scout or monitor)(=scout or monitor)and then use best estimates to and then use best estimates to determine risk level – if risk elevated we determine risk level – if risk elevated we control!control!

We MUSTWe MUST-- Understand bee/mite life cycleUnderstand bee/mite life cycle-- be able to ID mite & predict #be able to ID mite & predict #

Varroa mite – a pest or vector?

K-Wing or Wingless bees of value?

Illustration series from MartinIN: Mites of Honey BeesDadant & Sons, Inc 2001

Adult female miteenters larval cell as itcompletes development.She hides on side wallas pre-pupa spins cocoon

In 60 hours she lays1st egg (male).After 24 hours she laysfemale egg one every 24 hours

Her son (male) develops feedingon pupa & matesw/ sister as she matures

When adult beeemerges 1.3 adultfemale mites are mature – if eggson drone 3X are mature

SOLUTION?

Control Collapse w/ PesticidesControl Collapse w/ Pesticides

“Resistant” mites increase with each generation

Due to:

(1)selection pressure

(2)Sub-optimal exposure

EIL

ETAveragedensity

Time

Pest

den

sity

80

70

60

50

40

30

20

10

0

Economic Threshold

Apply controls

Avoid exceeding economic injury level

Mite NumbersMite Numbers

Increase seasonally

Mite NumbersMite Numbers

Vary between colonies & years

High mite yr

Low miteyr

MonitoringMonitoringOn broodOn brood - worker- worker - drone- drone

On beesOn bees - ether roll- ether roll - powdered sugar- powdered sugar

- alcohol wash- alcohol wash

In colonyIn colony- Sticky board- Sticky board

IPM THRESHOLDIPM THRESHOLDMMonitoring can supply a numberonitoring can supply a number

- a “guesstimate” - a “guesstimate”OOne or more numbers can be obtainedne or more numbers can be obtained

- use number(s) to evaluate mite population - use number(s) to evaluate mite population- one mite in sample = X mites in colony- one mite in sample = X mites in colony

(1=50 in U.S. -- 1=100 Europe)(1=50 in U.S. -- 1=100 Europe)

DDetermine an appropriate risk leveletermine an appropriate risk level- one mite vs 100 vs 1000?- one mite vs 100 vs 1000?

Assumption: 3000 mites in fall represents a Assumption: 3000 mites in fall represents a minimally acceptable conservative risk???minimally acceptable conservative risk???

BBalance of costs vs benefitsalance of costs vs benefits

Valadation of mite sample [bars] to actual numbers [background]Not perfect but good correlation

ThresholdThreshold

An acceptable level of pests [mites] An acceptable level of pests [mites] – determine necessity of further – determine necessity of further controlscontrolsA number to use to evaluate mite A number to use to evaluate mite control efficacy effortscontrol efficacy effortsAllows estimation of risk if no Allows estimation of risk if no pesticide chemical is integrated into pesticide chemical is integrated into the controlthe controlThe basis for IPM – a decision The basis for IPM – a decision process utilizing modern pest control process utilizing modern pest control practicespractices

ThresholdThresholdSpring/summer Spring/summer (April or May or Mid-June)(April or May or Mid-June)

Sticky boards – over 5-10 Sticky boards – over 5-10 Adult bees – over 3-4Adult bees – over 3-4 Brood – over 5%Brood – over 5%Exceeding threshold means additional control may be usefulExceeding threshold means additional control may be useful

Pre-fall Pre-fall (mid-August, Sept too late!)(mid-August, Sept too late!) Sticky boards – over 50-60 means additional controlSticky boards – over 50-60 means additional control Adult bees – over 10-12Adult bees – over 10-12 Brood – over 5-10%Brood – over 5-10%Exceeding threshold means additional (chemical)Exceeding threshold means additional (chemical)

control neededcontrol needed

IPM Mite Control TriangleIPM Mite Control Triangle

Varroa Mites – cultural controlVarroa Mites – cultural control

Apiary site locationApiary site locationComb cullingComb cullingSmall-sized cell baseSmall-sized cell baseRequeening w/ Resistant Requeening w/ Resistant (tolerant) stock(tolerant) stock Hygienic queen stockHygienic queen stock SMR (surpressed mite resistance)SMR (surpressed mite resistance) Russian stockRussian stock

From Martin: In Mites of the Honey Bee

Varroa Mites – physical controlVarroa Mites – physical control

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

Varroa Mites – physical controlVarroa Mites – physical control

Screened bottom board

Varroa Mites – biological controlVarroa Mites – biological control

No identified control agent so farNo identified control agent so farBest choice seems to be a virus or Best choice seems to be a virus or fungusfungus

Varroa Mites – Chemical controlVarroa Mites – Chemical controlMiticides - Apistan®; Checkmite+®; Amitraz®Miticides - Apistan®; Checkmite+®; Amitraz®Formic acid - Apicure®Formic acid - Apicure®; ; Mite-Away II® Mite-Away II® Other acids (acetic; oxalic)Other acids (acetic; oxalic)Essential oilsEssential oils Thymol Api Life VAR® Thymol Api Life VAR® [thymol + others];[thymol + others]; ApiGuard® ApiGuard® Others -thyme, citronella, clove, camphor, eucalyptolOthers -thyme, citronella, clove, camphor, eucalyptolSemiochemcials – Nasanov gland pheromones Semiochemcials – Nasanov gland pheromones + others+ othersMineral/vegetable oil (FGMO), estersMineral/vegetable oil (FGMO), esters Grease patties; oil machines, Sucrocide ®Grease patties; oil machines, Sucrocide ®Drying agentsDrying agents Diatomaceous earth, talc, powdered sugarDiatomaceous earth, talc, powdered sugar

Varroa Mites - Chemical ControlVarroa Mites - Chemical Control

Pesticides – natural/synthetic need to be Pesticides – natural/synthetic need to be approved (registered) for legal useapproved (registered) for legal useEmergency registration (i.e. Checkmite+) Emergency registration (i.e. Checkmite+) means emergency – temporary answermeans emergency – temporary answerNatural doesn’t mean less toxicNatural doesn’t mean less toxicDUMB chemicals (less toxic, not pre-DUMB chemicals (less toxic, not pre-packaged) need SMART beekeeperspackaged) need SMART beekeepers