Control or preventive measures and treatment
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Monitoring
editSeveral methods exist for monitoring levels of Varroa mites in a colony.[1] For a powdered sugar roll,[2] the sampler collects about 300 bees using a 1/2-cup measuring cup and places them in a jar with a wire mesh screen lid (1/8") along with 2 tablespoons of powdered sugar. They then gently swirl the bees for about a minute before turning the jar upside down and shaking for two minutes over a tray to capture the mites as they fall. Those mites are then counted, and the count is divided by three to find the number of mites per 100 bees. The sugar roll is typically done with the intent to prevent killing the sampled bees, but whether the vigorous shaking causes damage is not known. For an alcohol wash, which is the most effective method, the sampler collects about 300 bees using the same cup. The bees are submerged in alcohol with a concentration of 70% or higher. A lid is placed over the jar to seal it, and the mixture is shaken vigorously for two minutes before it is poured over a 1/8" wire mesh screen into a tray. The mites are then counted, and the resulting number is also divided by three. This method kills all sampled bees. The sticky board method does not kill any bees. For this method, a sticky board with a thick coating of petroleum jelly is placed under the brood chamber under a screened bottom board (or similar 1/8" wire mesh screen). The board is retrieved after three days, and the beekeeper takes a count of the mites on the board. This number is divided by three to find the average 24-hour mite drop. This method does not kill any bees, but takes longer for results.[citation needed]
Other strategie used are dust, which are useful in some ways but the effectiveness can be limited. Another form of controlling V. destructor is known as Mite trapping by using drones brood removal. Varroa Destructor tend to be in drone broods because they are capped longer than worker bees giving the mites more time to reproduce. Adding a drone comb to the hive increases the production of drones which acts as a trap to attract more mites. Removing the drone comb before the drones uncapped is very efficient to removing varroa mites that are reproducing in the cells.[3]
Reproduction, feeding, infection, and hive mortality
editMites reproduce on a 10-day cycle. The female mite enters a honey bee brood cell. As soon as the cell is capped, the Varroa mite lays eggs on the larva. The young mites, typically several females and one male, hatch in about the same time as the young bee develops and leave the cell with the host. When the young bee emerges from the cell after pupation, the Varroa mites also leave and spread to other bees and larvae. The mite preferentially infect drone cells, allowing the mite to reproduce one more time with the extra three days it takes a drone to emerge compared to a worker bee. This can cause genetic defects such as useless wings or viruses and fungi in the bee.[citation needed]
Varroa destructor typically reproduce during spring and summer by fall the mite population have grown. [4] some honeybees strains have the ability to reduce the population of the mite such as Russian honey bee. Varroa sensitive hygiene can recognize and remove mite-infested pupae. Bees that remove dead brood quickly are hygienic and are thought to be better at removing mites from the hive, as well. [3]
References
edit- ^ "Varroa mites: A step-by-step guide to monitoring in New York" (PDF). Pollinator Network at Cornell University.
- ^ Milbrath, Meghan (January 2018). "Varroa Mite Monitoring: Using a Sugar Roll to Quantify Infestation of Varroa Destructor in Honey Bee Colonies". Michigan Pollinator Initiative, Michigan State University.
- ^ a b "Methods to Control Varroa Mites: An Integrated Pest Management Approach". Penn State Extension. Retrieved 2021-05-11.
- ^ "Shibboleth Authentication Request". login.proxy181.nclive.org. Retrieved 2021-05-11.