October 11, 2016

Icing or Powdered Sugar for Varroa Control

The use of powdered sugar dusting is a popular non-chemical approach to the control of varroa mite in honey bee colonies and is seen as an effective integrated pest management control (that is, one that does not rely on chemical intervention but good management practices.)

The method has proved to be an effective means of reducing varroa mites in honey bee colonies, having a significant impact on mite reproduction. When the bees are covered with powdered sugar their bodies become slippery causing the varroa to lose their ability to cling to the bees, the granules of sugar interfere with the gripping surfaces of the varroas’ feet and they fall to the floor of the hive.

The powdered sugar also causes the bees to groom themselves more frequently causing more mites to be dislodged. This technique does not appear to have any adverse effect on adult bees or brood.  Unlike chemical methods this technique can be used at any time, even during a honey flow, as it does not contaminate the honey and as frequently as needed to control the mite. It can also be used as a method for detecting and assessing varroa mite infestation, within a colony.

How to apply powdered sugar to your honey bee colony

Take a sugar (or cocoa) shaker like the one pictured and use approximately 125 grams (1 cup) of sugar per single hive box. You should either have an open mesh floor or a sticky board in place, as the sugar does not kill the varroa but merely dislodges them. If not caught or dropped through a mesh floor the varroa will simply climb up into the frames again.

Smoke the colony as usual and put the sticky board in place on the hive floor if you are using one. Smoke the bees down from the top boxes. Remove the boxes and apply the sugar to the bottom box first, working up through the boxes. There is no need to remove the frames from the hive. Sift or dust the powdered sugar over the top bars of the frames and into the bees in the seams. Using a bee brush carefully brush the powdered sugar from the tops of the frames to between them.

The frequency with which you will need to apply this treatment will depend upon the level of varroa mite infestation.

The only down side to the use of powdered sugar for varroa control is if not used carefully it could potentially increase the chances of robbing by other bee colonies, during a nectar dearth and may also encourage ants. Even if you have an open mesh floor it is a good idea to apply a sticky board underneath to catch the sugar, this will also enable you to monitor the level of infestation in your hive.

Sticky boards can be purchased or made from cardboard or thick paper thinly smeared with a sticky substance such as vegetable oil or Vaseline.

More About Colony Management

Colony Collapse Disorder – Parasitic Fly Could be to Blame

A parasitic fly that hijacks the bees’ bodies and causes them to abandon their hives has been put forward as a possible explanation for Colony Collapse Disorder. Northern California scientists say the fly deposits its eggs into the bee’s abdomen, causing the infected bee to exhibit trance like behaviour, walking around in circles and then leaving the hive at night to die. This is what happens with Colony Collapse Disorder, in which all the adult honey bees in a colony suddenly disappear over night.

This research is another step in the right direction in finding the cause of Colony Collapse Disorder which is having a serious effect on the US bee industry. Research so far points to a combination of factors including pesticide contamination, a lack of the right food sources, mites, fungi, viruses and parasites.

Interaction among the parasite and multiple pathogens could be one possible factor in colony collapse, according to the latest study by researchers at San Francisco State University. It says the phorid fly, or apocephalus borealis, was found in bees from three-quarters of the 31 hives surveyed in the San Francisco Bay area. The combination of a parasite, pathogens and other stressors could cause die-off, lead investigator John Hafernik said. The parasitic fly serves as a reservoir that harbours pathogens ; honey bees from parasite-infected hives tested positive for deformed wing virus and other pathogens, the study found.

“We don’t fully understand the web of interactions,” Hafernik said. “The parasite could be another stressor, enough to push the bee over tipping point. Or it could play a primary role in causing the disease.”

The Varroa Mite Life Cycle Inside a Honey Bee Colony

One of the most widespread problems for beekeepers around the world is the mite known as Varroa destructor, previously known as Varroa jacobsoni. The varroa mite originated in Southeast Asia where it is a parasite of the Eastern honey bee, Apis cerana and was first discovered on the western honey bee, Apis mellifera, in 1960. It is thought that these pests came into the United States and Europe through illegally imported queens in the 1980′s and have since then had a devastating effect on some beekeeping operations.

Varroa mites are about the size of a pin head and are copper in colour, crab- shaped, with eight legs to the front and wide oval-shaped bodies. Female mites cling to the adult bees’ abdomen and feed off their haemolymph (blood). They do this by piercing the membrane between the plates of the bee’s abdominal segments. Although small, a varroa female is one of the largest ectoparasites (i.e lives outside the host body) known when considered in relation to the size of its host.

The female will enter a brood cell on a hive frame containing a larva and crawl underneath it, then hidden under the larval jelly she waits until the cell is capped. The female varroa mite then lays an egg every thirty hours. The first egg laid will be a male, with subsequent eggs being female. The maturing mites will feed on the bee pupa often causing developmental problems, such as wing damage.

The male egg develops into an adult in five to six days and a female in seven to eight. The male mates with his adult sisters and once the cell is uncapped and the bee emerges, the mature fertilized female varroa will leave the cell. The male varroa who never eats and any undeveloped females are left behind to die.

The mated females live on the young host bee until they enter cells to reproduce. In the summer varroa mites can live for about two-three months but survive for much longer in the winter. In summer mites usually manage two reproductive cycles which can produce eight daughters if using drone (male bee ) brood.

Developing female worker honey bees remain in a capped cell for twelve days and drones remain for fourteen days. Therefore more mites are able to reproduce in a drone cell than a worker cell and the female mite for this reason will actively seek out drone cells to lay her eggs. It has been calculated that a single varroa mite laying in a worker cell will result in 1.8 mites emerging with the adult bee compared to 2.8 mites from a drone cell.

If infestation is left unchecked the colony will die out within three to five years. As the adult honey bees within the colony become weakened and have reduced life-spans, the normal hive routine will be disrupted which leads to poor hygiene, leading in turn to bacterial and viral diseases thriving.

by Maggie Roberts

To learn more about beekeeping see http://www.beekeepingbeesandhoney.com/