IPM for Beekeepers: Managing Varroa Populations. Landi Simone Essex County Beekeepers Society June 12, 2007 (rev. 6/9/09)

Transcription

1 IPM for Beekeepers: Managing Varroa Populations Landi Simone Essex County Beekeepers Society June 12, 2007 (rev. 6/9/09)

2 Review of IPM Principles IPM means managing pest populations, not eradicating them. Understand pest life cycle. Monitoring is critical. Know treatment thresholds. Timing of treatments (when needed) is critical.

3 Components of an IPM Program IPM Components Pest Identification Understand Life Cycle Monitor Pest Levels Determine Treatment Level Determine Treatment Stragegy Direct Methods (Usually chemical) Apply Treatment Indirect Methods (Physical, mechanical, biological, cultural) Evaluate and Redesign

4 Varroa: Pest Identification Small pin-head size 8-legged brown to reddish brown parasite sucks hemolymph from bees Present in almost all U.S. colonies and in most countries LEFT UNTREATED, WILL CAUSE COLONY COLLAPSE WITHIN TWO YEARS.

5 Life Cycle of Varroa destructor Adult female mite feeds on bees 5-13 days then enters brood cell 24 to 60 hours before capping. Lays first egg 60 hours after capping, then every 30 hours thereafter First mite to emerge is male. Subsequent mites are female, which mate with male and feed on pupa Mature females emerge with bee; immatures and male remain in cell and die Mites are transferred bee to bee in brood nest; prefer nurse bees for cell access

6 Effects of Varroa: Individual Bee Workers Life span reduced by 50% (especially bad for overwintering bees) Food and wax glands damaged Reduced disease resistance Drones Reduced sperm count Less likely to mate successfully BAD QUEENS

7 Effects of Varroa: Colony Level Pierced exoskeleton permits entry of multiple viruses normally present but dormant in the hive PMS: Parasitic Mite Syndrome. Easily confused with foulbrood Colony collapses under viral load, usually in late summer-fall

8 Seasonal Population Dynamics Varroa is phoretic on adult bees in winter (ride + meal) Breeds in brood come spring, esp. drone brood. For every mite you see on a bee, there are two in the brood. Populations peak in July and August

9 Understanding Varroa Population Dynamics

10 So How Do I Know if my Bees Have Varroa Mites????

11 Monitoring Pest Levels: Powdered Sugar Roll Add 400 bees from the brood nest (about 2 fingers) in a quart mason jar with hardware mesh screen on top Add 1 Tbsp. powdered sugar & shake Pour out sugar onto white paper or in pail of water Count mites Release bees

12 Monitoring Pest Levels: Sticky Boards Easiest to use with a screened bottom board (SBB) but can be used without Use commercial sticky board or use homemade tileboard or plastic smeared with petroleum jelly Do NOT use PAM, shortening, or vegetable oils. They do not give the same result. Place below screen for 1 to 3 days Count mites Convert to equivalent 24 hour count

13 Determine Treatment Thresholds At a minimum, sample from late July to early August: 24-hour natural fall on sticky board: Take action if >50 mites Powdered sugar roll: Take action if > 10 mites

14 Treatment Thresholds in Winter/ Spring Late Winter Sampling (early to mid-march) 24 hour natural fall on sticky board: Take action if >2 mites Spring Sampling (late March to mid-june) 24 hour natural fall on sticky board: Take action if >10 mites Powdered sugar roll: Take action if >3 mites NOTE: Honey supers cannot be on hives at the same time as mite treatment.

15 IF YOUR BEES NEED TREATMENT, GET IT ON BEFORE THE END OF JULY! Unless you d rather have dead bees.

16 Prior to the winter of , we recommended August 31 as the treatment deadline but poor nectar flows in 2008 combined with early onset of cold weather led to many mite-related losses because the bees did not have time to raise enough healthy bees to overwinter successfully. We have changed the recommendation to July 31.

17 It bears repeating. Don t be a mutt! Treat your bees before July 31 or you won t have bees next spring!

18 What about fall honey?? How do I treat my hives and still get a fall crop? How do I keep wax moths out of my supers in late summer and early fall without using chemicals?

19 One Beekeeper s IPM Schedule Start removing honey supers in July, one apiary at a time. As you leave with the honey, slip sticky boards under hives screened bottom boards. Extract honey. Return 2-3 days later and count mites on sticky boards. Determine which colonies need treatment.

20 IPM Schedule, cont d. Return extracted honey supers to original colonies, if possible, for bees to clean out for a few days. (IPM technique for AFB) When supers are dry, stack all dry supers on colonies not needing mite treatment. These hives will bring in a fall crop. Treat colonies that need it. Repeat for the next apiary. In October, remove all supers for storage. Extract any fall honey the bees have collected.

21 Remove Varroa Treatments After the Specified Time Unless you want to lose more treatment options due to mite resistance.

22 Hard Chemical Treatment Options - Smart Chemicals for Dumb Beekeepers Dr. Medhat Nasr Apistan (fluvalinate) Pyrethroid Low toxicity to beekeeper Was highly effective (99%) in killing mites Widespread resistance due to misuse. Accumulates in beeswax. Now known to be toxic to bees. Check-mite (coumaphos) Organophosphate High toxicity to beekeeper Was highly effective (99%) in killing mites Widespread resistance due to misuse. Accumulates in honey and in beeswax. May affect developing queens.

23 Hard Chemical Treatment Options, cont d. Amitraz Amidine - affects nerve receptors Relatively low toxicity to beekeeper; higher bee toxicity Queens stop laying while in use. Not licensed for use in the U.S. Not commercially available. Some resistance reported in Europe. Degrades quickly in honey and beeswax. Fenpyroximate (Hivastan) *NEW* Affects mitochondial electron transport Toxicity to humans and bees similar to Amitraz. High toxicity to aquatic life. (Disposal issues.) Accumulates in beeswax. Not currently available under Section 18 in NJ, but NY has a Sec. 18.

24 Fluvalinate Toxicity NEWS FLASH!!! New research by Mary Ann Frasier at Penn State in 2008 indicates that Apistan (fluvalinate) is significantly more toxic to honey bees than previously thought. PENN STATE RECOMMENDS AVOIDING APISTAN COMPLETELY.

25 Chemical Resistance Mites which survive a chemical treatment due to a mutation live to parent subsequent generations, passing on the resistance gene. Such mutations usually come with a down side resistant mites do not reproduce as well as nonresistant mites if no chemical treatment is present. Therefore, left untreated for a period, mite populations will often revert to a non-resistant state and chemical treatment will again become effective (though not at previous level.) ROTATE TREATMENTS!

26 Testing for Resistance Refer to USDA Beltsville Bee Research website: for detailed directions Summary: Staple a 3/8 x 1 piece of strip to be tested to a piece of index card and place in a wide mouth pint-size mason jar with screened lid cut to fit. Collect 1/4 cup of bees from brood nest (not queen!) and add to jar. The hive must have >5 mites on an ether roll to do this test.

27 Testing for Resistance, cont d. Store jar at 86º F (30º C) for 6 hrs. Invert jar 10 cm above a white piece of paper and hit base 3 times with your hand. Count mites on paper. Call that # P. Knock bees down, remove card with strip, add 1 cup of windshield washer fluid. Replace screen with solid lid. Shake 5 minutes. Replace screen & pour fluid onto filter cloth (e.g. nylon curtain fabric) held over a bucket. Add another cup of fluid, swirl and pour through again.

28 Testing for Resistance, cont d. Count the mites on the filter cloth. Call that number F. The percentage of mites killed by the chemical tested is: % Kill = P X 100 (P + F) Note: If the total number of mites P + F is less than 5, The test is invalid. Pick another hive with more mites.

29 Hard Chemicals: Check-Mite Plastic strips with chemical: Use one for every 5 frames of brood/bees (2 per deep brood box.) % efficacy if no resistance Leave strips in 42 to 45 days, then REMOVE. Honey supers must be off hives during treatment. Wait two weeks after treatment before supering. No temperature restrictions. Neurotoxin. Wear chemical resistant nitrile gloves, NOT bee gloves. Requires Pesticide Applicator License.

30 Hard Chemicals: Apistan Plastic strips with chemical. Use one for every 5 frames of brood/bees (2 per deep brood box.) 97-99%+ efficacy if no resistance Temperatures should be at least 50º. Leave in 42 to 56 days, then REMOVE. Honey supers must be off hives during treatment. Wait two weeks after treatment before supering. Wear latex gloves, not bee gloves.

31 Soft Chemical Treatment Options: Dumb chemicals for Smart Beekeepers Dr. Medhat Nasr Thymol-Based: Apilife Var Apiguard Organic Acids Formic (Mite-Away II) Oxalic Trickling Method Fogging Sugars Sucrocide Powdered Sugar ( Dowda Method)

32 Apilife Var Essential oil-based treatment: thymol, eucalyptus, camphor, menthol in vermiculite tablets or wafers. Each package contains two wafers. Break a wafer into 4 pieces and put on top bars of brood nest. Repeat treatment 3 to 4 times 7-10 days apart % efficacy. Average 75%. Temperature dependent. Range should be 64º - 86º. Do not use above 90º. No resistance reported. Honey supers should be off during treatment and not put back on for 30 days following treatment. Use disposable latex gloves. Eye hazard. Can burn skin.

33 Apiguard 85-95% efficacy. Honey supers must be removed but can be returned immediately following treatment. Temperature range 60º-105º. Leave open tray of gel on brood nest for 14 days (2 in a double deep). Repeat treatment once. Also kills tracheal mites. Eye damage/skin irritant. Manufacturer recommends wearing nitrile gloves. Reverse inner cover or use spacer to provide 1/4 space above gel tray.

34 Organic Acids Formic Acid Oxalic Acid Original U.S. formulation was a gel, Apicure, but packaging problems led to its being pulled from the market. Now available as liquid-soaked pad, Mite-Away II. Trickling Method Fogging (Not practical for most hobbyist/sideliners.) Lactic Acid - used in Europe; not available in the U.S.A.

35 Formic Acid: Mite-Away II Temperatures should be between 50º-80º. If temperatures exceed 82º in the first 7 days of treatment, pads should be removed % efficacy. 21 day treatment. Honey supers may go on immediately after treatment but should not be harvested for 2 weeks. Remove outer plastic bag but not inner. Use spacer rim and shims under pad. Apply pad hole-side down. Inhalation and contact hazard. Stand upwind and use nitrile gloves. (Respirator requirement recently rescinded.)

36 Mite-Away II Screened bottom boards should be closed during treatment. Entrance reducers should be removed.

37 Oxalic Acid, Trickling Method Not a stand-alone treatment. Colony must be broodless (Late October - December.) Bees should be reduced to 2 deeps, or equivalent. Use acid-resistant gloves. Knocks down mite population phoretic on wintering bees.

38 Oxalic Acid: Trickling Method, cont d. Make a 3.2% solution by adding 3 level tablespoons (34 gms) oxalic acid crystals (dip + sweep method of measuring) to 1 liter of 1:1 sugar syrup. (Make syrup by putting 5 pounds of sugar in a 1 gallon container. Fill with hot water & stir.) Use a syringe to trickle about 5 ml. of acid solution in every space between frames occupied by bees. (Dr. Medhat Nasr s rule of thumb was 50 ml total for strong colonies, 40 ml for weak, divided between the brood boxes.)

39 Sugar Treatments Sucrocide Safe for bees (open brood?) and beekeeper. Inexpensive. Labor intensive Dowda Method See May 2007 ABJ article by Randy Oliver. Good, safe way to control Varroa populations during honey flow. Efficacy depends on frequency of application.

40 Sucrocide (Sucrose Octanoate esters) Mix 1.5 Tablespoons per gallon Spray each and every frame of bees, both sides. Repeat at weekly intervals 3x to cover full 21 day brood cycle. Very labor-intensive. No restrictions on honey supers. Temporary eye irritant.

41 Powdered Sugar Dusting Use 1 cup sugar per deep. Place frame with metal screen stretched over it over frames and shake sugar on screen. Use bee brush to dust through screen. Repeat for second deep. Approx. 1/3 of phoretic mites will drop off with each treatment but not die. Repeat as often as desired weekly, bi-monthly or monthly. Must be used with screened bottom board. No honey super restrictions. Does not kill mites. Must Be used with screened BB.

42 Other Methods: Mineral Oil Food Grade Mineral Oil (light viscosity: 70 FG. Available from STE Oil, Texas. Fogging (Pedro Rodriguez method) has been shown not to work. Trickling on frames - mixed results. Some beekeepers report good control with very frequent use (R. Harvey) ; others have not found any benefit. No good scientific studies available. Beekeepers using this method successfully do not overwinter in cold climates. Oil treatment seems to work best in warm weather and with frequent repetition.

43 Other Methods: Drone Trapping Deliberately introducing and culling drone comb can be a highly effective method of Varroa control. Can use commercial drone foundation or introduce an empty frame, which the bees will almost always draw out into drone comb. Remove the comb when brood is capped and dispose of brood + mites by freezing. Return to bees for cleaning and/or reuse.

44 Drone Culling One drone brood frame per month can delay necessity for other treatments. Two frames may be able to eliminate other treatments. Drawbacks: If you fail to remove in time, you re breeding mites. Requires an organized beekeeper! Long-term effects of reducing an alreadydepleted honey bee gene pool.

45 Follow-Up Monitoring All Dumb Chemical treatments, mechanical & biological methods need Smart Beekeepers to follow-up by rechecking mite levels after treatment. Failure to do so can cost you your bees. Smart Beekeepers use a variety of techniques in combination with one another. Find a system that works for you and use it.

46 Hope you learned something!! Photo credits: MAAREC, Dr. Dewey Caron, Bayer, Chemicals LAIF, Wellmark International, NOD Apiary Products, Ltd., Carol Margulies, Landi Simone