DETERMINING MITE LEVELS

READING THE RESEARCH Oogenesis of Varroa mites remains arrested in the previtellogenic stage during the phoretic phase on the adult bees and is activated shortly after the invasion of a brood cell.

Outline Introduction Topic: Determining Varroa Mite Levels What is IPM Basic Knowledge of Mites Why Test? Which Test(s) to Use? When to Test? How to Test? What are Thresholds in IPM When to Treat? IPM treatment strategies

IPM – Integrated Pest Management Dewey M. Caron I=INTEGRATED – ideally use of more than pesticide chemical control P=PEST – mites sure but applicable to any of the 3 P’s M=MANAGEMENT – as you mange the bee population you manage the P’s “Several techniques are employed simultaneously to solve specific pest problems” Alternative BMP’s Best Management Practices names: Alternative Treatments (non-pesticide)

IPM Dewey M. Caron 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!

Four Fundamental Strategies for Pest Management Dewey M. Caron Do nothing Reduce numbers of pest Reduce susceptibility of the host Use combinations of the last two

IPM Essentials MONITORING We MUST -Understand bee/mite life cycle - be able to ID mite & predict # Mite levels fluctuate within & between: seasons, bee yards and colonies. We must carefully test and then use best estimates to determine risk level IF RISK LEVEL WARRANTS – THEN TREAT

enters larval cell as it completes development. She hides on side wall 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

In 60 hours she lays 1st egg (male). After 24 hours she lays female egg one every 24 hours

Her son (male) develops feeding on pupa & mates w/ sister as she matures

When adult bee emerges 1.3 adult female mites are mature – if eggs on drone 3X are mature

THINGS TO KNOW WE CAN ONLY ESTIMATE VARROA LEVELS VARROA LEVELS VARY WITH TIME OF YEAR SIZE OF COLONY AMOUNT OF BROOD PREVIOUS VARROA TREATMENT NO ONE TEST FOR VARROA WILL FIT ALL SITUATIONS SOME TESTS ARE MORE ACCURATE

WHY TEST? OBVIOUS: NOT SO OBVIOUS: PREVENT COLONY LOSS MITE RESISTANCE KNOW WHAT’S COMING UP PREVENT OVERTREATMENT SAVE MONEY

WHICH TEST TO USE? MITE DETECTION METHOD SUMMARY METHOD COST TIME VISITS *SENSITIVITY ** RELIABILITY Visual Inspection zero 2 min 1 very low very low Opening Drone Cells zero 5 min 1 high low Ether Roll low 5 min 1 low medium Washing low 5 min 1 high high Sugar Shake low 5 min 1 high high Tobacco Smoke moderate 30 min 1 low low Natural Drop moderate 24 hrs 2 low high Miticide high 24 hrs 2 very high? very high? *SENSITIVITY: ability to detect very small numbers of mites **RELIABILITY: can depend on the test results ? Are the mites resistant to the miticide?

WHEN TO TEST? OBVIOUS ANSWER: In time to prevent colony loss NOT SO OBVIOUS: Brood = Mites and each area/climate varies Mite levels: lower in spring to higher in fall Test in time to allow treatment before honey flow Remove honey asap and test.

HOW TO TEST 1. Natural Drop 2. Sugar Shake

HOW TO TEST Alcohol Wash Visual - Drone Brood

IPM THRESHOLD Monitoring can supply a number - a “guesstimate” One or more numbers can be obtained - use number(s) to evaluate mite population - one mite in sample = X mites in colony 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 Basics of the rational of IPM. It assumes a pest situation (host honey bee) can function with some base level of pests (mites) and still function normally. We determine a threshold, test the threshold and then can assign some level of risk to exceeding the threshold level of pests.

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

MITE NUMBERS & TREATMENT TIME OF YEAR NATURAL DROP ALCOHOL WASH SUGAR SHAKE VISUAL DRONE BROOD SPRING AHEAD OF HONEY FLOW 1-2 (8d) 1% of sampled bees NA/ SUMMER /FALL END OF HONEY FLOW 10 (30d) 5% of sampled bees 7% of sampled bees 1% of drones sampled (100) WINTER OCT-NOV 1-2 N/A This numbers on this chart are the averages of my research. They are likely on the conservative side. ** NUMBERS AND PERCENTS ARE GUIDELINES FOR TREATMENT ** BLACK NUMBERS ARE TREATMENT THRESHOLDS ** RED NUMBERS ARE DAMAGE THRESHOLDS

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 These threshold numbers seem high

Let’s Not Lose Control - Chapleau THANK YOU - Lance