Bees are critical to our ecosystem – everything from the flowers we love to the foods we eat relies on these remarkable little pollinators. But like every other living thing, bees can be vulnerable to disease. Varroa mite is one of these diseases which affect bees.
What is Varroa Mite?
Among the worst enemies of the honeybee, this mite is a tiny external mite. It originated in Asia, and was first discovered in Java, Indonesia more than a century ago. Local Indonesian bees have, over millennia, developed ways to overcome the mite, however, when European settlers brought Western honeybees to Asia, they fell prey to the Varroa mite. These infested colonies were returned to Europe and, thereafter, the mite has spread worldwide.
The Varroa mite is an arachnid (it has eight legs) with a mouth made for piercing and sucking. It grips onto the body of the bee (usually on its back or belly) and feeds on its hemolymph (bee blood).
How does Varroa Destructor Affect Bees?
- Weakens the bee’s immune system
- Transmits viruses
- Kills colonies
- Worker bees come in contact with the mite via bees from other colonies.
- Worker bees usually carry these little mites back into the hive.
- The mites (which are blind and deaf) invade the brood chambers of the hive. They sneak into the cells with the bee larvae and are capped in here by the unsuspecting worker bees.
- Mites lay eggs in the cells and feed on the liquid brood food, then on the bee pupae.
- The Varroa population in a beehive can double every four weeks.
- The baby bee hatches in a severely weakened and diseased state.
Varroa mites can also attach to and infect adult bees, and an adult Bee mite can live on an adult bee for three months. An infestation causes extreme levels of loss to the beekeeping industry worldwide.
Millions of honeybee colonies have been destroyed by these parasites which also carry viruses (including Deformed Wing Virus), harmful bacteria, and fungal infections. The risk from these infections transmitted to honeybees by these mites will further weaken bee colonies. Bees that are infected will have a shortened lifespan and can be unable to fly, may become paralyzed, and may experience brain dysfunction.
A bee colony that has been infested with this mite will die within three years if effective treatment is not carried out.
Signs of Varroa Mites in Your Beehive
There will initially be few symptoms of an infection with the mite.
Signs and symptoms of infestation when they do occur include:
- Scattered or abnormal brood pattern
- Brown, black, or red spots on white bee larvae
- Deformed baby bees (especially wings and legs)
- Mites visible on adult bees
- Crawling or crippled bees
- Impaired flight
- Lower return rate to the hive
- Reduced weight in worker bees
- Reduced lifespan
- Sunken or chewed cappings in the hive
- Slumped larvae in the side or bottom of cells
- Death of colony
Best Varroa Mite Treatment and Prevention Tips
Treating the mite infection promptly is critical to mitigating its risks.
- Monitor your beehives closely and regularly.
- Breed mite-resistant bees.
- Split your colony into new hives.
- Use screened bottom boards for better hive ventilation (only suitable in warmer areas) and to enable mites to fall from the hive.
- Use a heating chamber – They can’t survive at above 47C and bees can withstand this temperature for some time.
- Paint hive boxes a dark color to make the hive hotter.
- Use small foundation cell frames.
- Use a drone foundation sheet to trap Varroa mites.
- Apply mint and thyme essential oils – soak strips of absorbent material in these and leave them between the beehive frames. Leave for at least three days but no more than seven days. Repeat this treatment after three weeks. Use screened bottom boards in the hive.
- Plant mint and thyme around or near your hives.
- Place bee grooming aids at the entrance to the hive.
- Powdered sugar encourages bees to groom themselves and each other and remove mites. Make your own powdered sugar (do not use a commercial product as it contains starch, bees do not like this).
Pulverize white cane sugar in a blender on low and use half a cup per hive. Apply it to the uppermost box and distribute it evenly through the frames through a Varroa treatment screen. Use your smoker if bees try to leave the hive during treatment. Use a screened bottom board.
- There are various commercial treatment product options, including Mite Away Quick Strips, Synthetic chemical Varroa Mite Treatments, and various vaporizer kits.
Bees are very intelligent and will naturally suspect Varroa mite in their hive if there is any indication it is present. If they suspect this, they will uncap and cannibalize their pupae if there is a proliferation of mites in the hive.
Prevention is better than cure – so inspect your hives frequently so you can take the required steps to protect your little bees.