Jeff Harris
Extension/Research Apiculturist
Department Biochemistry, Molecular Biology, Entomology & Plant Pathology
Mississippi State University, MS 39762
Mississippi Agricultural &
Forestry Experiment Station

Varroa destructor Anderson & Trueman

3
2
4
1
5
9
6
8
7

Damage to Bees: Viruses!!!

Parasitic Mite Syndrome
(the end is near)

(apply chemicals routinely in spring and late summer)

• No thinking  just doing (assembly line)
• Can be effective early in a pest control program
• Saves labor costs often associated with nonchemical means

Chemicals in bee colonies may lead to: contaminated wax and honey mites that are resistant to chemicals harmful effects to bees

Chemical Control of Varroa
• 1 st legal varroacide; 1987 from Mavrik®
• 1990 as Apistan®; 0.7 g active ingredient per strip
• 10% moves into hive components over 8 weeks
• pyrethroids poison Na+ channels of nerves tau-fluvalinate

tau-fluvalinate
• Varroa mites resistant to chemical by 1995
• Health effects on honey bees
– Smaller queens
– Low survival of drones
– Low body weight of drones
– Reduced sperm counts from drones
• 5 year half-life for residues in hives

Product
Table 3 – Commonly Used Legal Formulations to Control Varroa Mites
Active
Ingredient
Mode of Action Formulation
Health
Effects on Bees
Residue
Time in
Combs impregnated strips yes years Apistan
CheckMite+ tau -fluvalinate poisons voltage-gated sodium ion channels in nerves coumaphos poisons the enzyme acetyl-cholinesterase in nerves
Apivar amitraz binds to octopamine receptors in nerves impregnated strips impregnated strips yes yes years short
ApiLife Var
Mite Away II thymol formic acid binds octopamine and
GABA receptors in nerves a strong acid that disrupts electron transport in mitochondria of cells solid wafer soaked onto pads that release fumes yes yes short short

(let my bees survive without the use of drugs)

• Increase distance between colonies in apiary
• Increase distance between apiaries
• Place colonies in irregular groups and not rows
• Paint hives different colors
• Don’t put sick and dying colonies onto stronger ones
• Drone Trapping
• Use Varroa-resistant bee stock

• My honey and wax are more likely to be free of harmful chemicals
• My bees will not suffer from toxic effects of insecticides

• Bee colonies will die from varroa mites
• Most small scale beekeepers cannot control breeding of their bees
• If a small scale beekeeper is isolated, the risks of inbreeding are high

Sugar Shake
• 300 worker bees from brood-nest
• 1 fluid oz. = 100 bees
• 2 Tablespoons of powdered sugar
• Coat the bees, wait 3-5 minutes, shake out sugar and mites

Alcohol Wash (70% ethanol)
(alternative : 15-30 drops liquid dish detergent per pint of water)

5% threshold for late summer means:

Table 2 – Number of Colonies to Sample for Apiary-Level Treatment Decisions
No. Colonies in Apiary
No.
Sampled
>20
20
10
4
5
3
8
6
• Colonies should be spread throughout apiary
• Use average mite load to decide if whole apiary is treated

Position of Drone Frames
Brood Nest
H H W D W W D W H H
(view from top)

ARS Russian Honey Bees
• from far-eastern Russia
• believed to have longest exposure to Varroa mites
• selectively bred at Baton Rouge lab
• good varroa resistance
• good tracheal mite resistance
• good overwintering

Varroa Sensitive Hygiene

Minnesota Hygienic Bees

sample (1% )
Did treatment work?
sample (5-10%)
Honey
Production
Winter Bee
Production
Jan Feb Mar April May June July Aug Sept Oct Nov Dec
Apistan, Apivar, etc.
Thymol, Formic Acid, etc.

Varroa IPM Summary
• Sample in February and again in
August/September
• Treat with chemicals only when mite populations exceed thresholds
• Use a resistant stock
• Use drone comb as traps
• Use screen floors

Gilles San Martin