Varroa Biology and Control. Introduction to the Varroa Mite. Damage 2/28/2014

Transcription

1 Varroa Biology and Control Dr. Dan Schmehl University of Florida Entomology and Nematology Department Harvey L Cromroy Introduction to the Varroa Mite Varroa destructor (Anderson and Truemann) is a pest of the Western Honey Bee (Apis mellifera L.) Thought to be V. jacobsoni Oudemans until Spread to the United States in the mid-1980s One of the largest ectoparasite to host ratios Feed on the hemolymph of immatures and adults Damage Shorten lifespan of adults and kill immatures Spread numerous diseases, including Deformed Wing Virus (DWV),and Israeli Acute Paralysis Virus (IAPV) Reduction in feral colonies Many areas of the United States have exclusively managed colonies Hard to estimate colony loss Likely have killed hundreds of thousands worldwide Billions of dollars in economic loss 1

2 Ubiquitous Distribution Spread of Varroa Native to Asia Apis cerana- native host Not a pest Only affects drones restricted in capped cell Workers kill mites in mandibles Spread of Varroa In 1970s, Varroa was discovered in Apis mellifera Originally introduced to Europe 2

3 Spread of Varroa Robbing Drifting Introducing bees to coloniessplits, strengthening, etc. Migratory Beekeepers Reproduction (Swarming) Maryann Frazier Varroa Life Cycle Tony Linka Illustration Life Cycle COLOSS 3

4 Life Cycle Huang 2013 Monitoring Powder Sugar Shake Quick, easy, relatively non destructive Mason jar (1/8 mesh), powder sugar, pan Collect ~1/2 cup adult bees from brood frames Threshold ~ 15 mites Disadvantage: Small subset of bees Monitoring Ether Roll Quick, easy subset of bees sampling Mason jar (1/8 mesh), ether Collect ~1/2 cup adult bees from brood frames Disadvantage: Small subset of bees, destructive Threshold: ~ 15 mites 4

5 Monitoring Alcohol Wash Accurate sampling on a subset of bees Place ½ cup bees in a closed container Wash bees with alcohol and use a sieve to collect mites Disadvantage: Small subset of bees, destructive Threshold: ~ 15 mites Monitoring Sticky Sheet Comprehensive look at colony Sticky sheet, bee guard Threshold ~ 60 mites Disadvantages: time consuming Varroa Control Threshold to treat colonies: 3000 mites Several types of control Chemical control (in-hive) *Do not use during honey flow! Always wear gloves! Mechanical control Others 5

6 Varroa Control Chemical control (in-hive) Apistan (fluvalinate- pyrethroid), Checkmite (coumaphosorganophosphate) Thymol- (Apilife Var) Recently Apivar (Amitraz) Varroa Control Mechanical control Drone Comb Screened bottom boards Powder sugar packages Others Varroa-resistant honey bees Honey bee breeding- hygienic and grooming behaviors RNA Interference (RNAi) Apistan tau-fluvalinate (pyrethroid) Registered in 1990 for honey bee use Use 1-2 strips per brood chamber Leave strips in hive for 6-8 weeks 6

7 2/28/2014 Checkmite Coumaphos (organophosphate) Registered in 1998 for honey bee use Use 1-2 strips per brood chamber Leave strips in hive for days Very effective against small hive beetle Apivar Amitraz (formamidine) Registered in 2013 for honey bee use Use 1-2 strips per brood cover Leave strips in hive for 42 days, remove Apilife Var Thymol Best in early spring or late fall (between 68 and 86 ) Place tablet (broken into four pieces) on brood nest Replace every 7-10 days for a total of 3 applications Apiguard also available (not discussed here) 7

8 Brushymountainbeefarm.com/ 2/28/2014 Other chemical controls Oxalic acid Hops (Hopguard) Formic Acid (Mite-Away) Other Essential Oils Mainebeekeepers.org anacortescenterforhappiness.org Essential Oils EO does not confirm safety Generally considered less toxic, but still may pose a risk Lack of standardized procedures Including testing, application descriptions, and re-application times Hive residues Fantastic option, but needs more investigation anacortescenterforhappiness.org Mechanical Drone comb Varroa preferentially attracted to drone brood Place combs in colony Wait until drone brood is capped Remove frame and place in freezer Kills brood and Varroa Replace comb in colony and repeat Workers will remove dead brood, Varroa 8

9 Mechanical Screened bottom boards Reduces Varroa numbers in colonies (~ 14%) Natural mite fall exits hive and is unable to reenter. Mechanical Powder sugar Pour ~1 cup powder sugar on new packages Wait a few minutes and shake packages for ~ 1 minute to dislodge any mites attached to bees Not terribly effective Varroa Resistant Honey Bees Colony monitoring strategy select for the strongest bees Record honey yields, brood patterns, survival, swarming behavior Breed queens from strong colonies to begin new colonies Survival of the fittest Disadvantage: time consuming 9

10 Hygienic Honey bees Breeding programs aimed at hygienic and grooming behaviors Not only helps to eliminate Varroa, but other brood related maladies AFB, EFB, chalkbrood, etc. Varroa Sensitive Hygiene (VSH) Developed at USDA-ARS Baton Rouge Bee Lab Particularly good at removing Varroainfected brood Breeding resistant lines appears very promising extension.org beeinformed.org RNA Interference Control at the molecular level sirnas interfere with Varroa physiological processes. Targets can include: Reproduction Pesticide resistance For more information visit: UFhoneybee.com Follow us on 10