Friday, November 19, 2010

LESSON 87: PESTS & DISEASES PART 3 VARROA MITES

smalldavidatbarnHello from Long Lane Honey Bee Farms in central Illinois. We’re David and Sheri Burns and now the 2011 bee season preparation has started. Package bee orders are pouring in. Orders for woodenware and bee supplies all point to the bee season is underway. in 5 days we sold 1/4 of our available packages. Unbelievable! I so much enjoy answering the phone and meeting other beekeepers or beekeepers-to-be.
family1Here’s a picture of our family. Sheri and I have six children ranging in age from 28 years old to 3 years old. Three girls and three boys. Almost everyone in the picture has helped us in our bee business, even Grandma and Grandpa in the back row. We’ve worked hard to establish Long Lane Honey Bee Farms and we want to thank all of you who have blessed us with your business.
Throughout most of the US beekeepers have put their bees to bed for winter. That is merely a figure of speech because bees do not hibernate during the winter. Instead, they cluster, remain calm and eat small amounts of honey and pollen to make it through the cold winter months.
nucWe have heard back from so many customers who love our queens, nucs, packages and woodenware, and we appreciate that. So many people are requesting our 4-frame nucs for spring.
These are little colonies that we make up in the spring with our queens on 4 frames of honey, pollen, brood and bees. A day does not go by without someone wanting to order nucs in advance.
nucs
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LESSON 87: PESTS & DISEASES PART 3 VARROA MITES
Today I want to educate you on the varroa mite, but I do not want you to become discouraged or defeated by this honey bee parasite. We can keep bees even with varroa mites. Mites are everywhere in our world. You’ve probably got a few in your house and probably on you at one time or another, such as chiggers or dust mites. So do not become a hypochondriac about your bees having mites. Do not freak out or overreact. There are many approaches to dealing with mites. But, for  you to be a successful beekeeper, you need to be well informed about Varroa destructor.
HISTORY OF VARROA DESTRUCTOR
The varroa mite was first introduced into our country in 1987, although the literature identifies the spotting of one varroa mite in Maryland in 1979. Since 1987 mites have spread rapidly throughout the US.
The mite was first identified as Varroa Jacobsoni but later correctly identified as Varroa destructor (Anderson and Trueman 2000). It is the number one killer of honey bees in the US. As an ectoparasite  (lives outside of the honey bee) it is one of the largest parasite on the planet compare to its host.
It is not a natural parasite to our honey bee, Apis mellifera. It’s original host was Apis cerana. But, like many pests, it jumped species and Apis mellifera was not able to cope well and most feral colonies, wild hives, were destroyed by the mites in the early 1990s.
LIFE CYCLE
Miteondrone1Varroa mites are tiny but visible with the naked eye. In this photo, I pulled out a drone pupa and you can see the tiny mite on the lower abdomen of the drone. The mites that we see on our bees are the adult, female mites also called the foundress mite. These adult females are dark, reddish brown in color. Male mites are never seen outside the cells and they never turn dark but remain white or a light color. Mites only reproduce in the sealed cells of a bee hive, never outside the hive.
The varroa mite enters a hive through the front entrance, riding on other bees. Drones are allowed to enter any hive and drones are common carriers of mites, transferring them from hive to hive. Once in the hive, the adult, foundress mite will look for a young nurse bee and climb on her back and will latch on to the thorax where the wings attach or just behind the head. Mites feed on bee blood, known as hemolymph.
Because the bee is exoskeleton, the mite cannot penetrate the outer plates of the bee so it moves to the overlapping segments of the abdomen to the soft tissues and pierces through with its mouth parts. These areas on the honey bee are known as the innersegmental membranes.
When the bee larva is 8 days old it gives off distinct pheromone signal to adult bees who begin to seal the cells. However, that same pheromone signal is picked up by the varroa mite as an indication that it is time to enter the cell.
The mite makes her way into the bottom of the cell and buries herself beneath the royal jelly in the base of a cell.  Mites have a snorkel like apparatus that they use to breathe while hiding under the royal jelly. These specialized tubes are called peritremes and are thin, pale-colored tubes located just between the last two pairs of legs.
Once the cell is capped and the bee larva has spun its cocoon the mite will feed on the larva and will begin laying eggs about 3 days after the cell is capped. Most female mites lay between 4-6 eggs, the first being a male mite, and the remaining 4 being females that mate with their one brother in the cell.
Unlike bees, mites do not go through larva and pupa stages, instead they go through 4 developmental stages: egg, protonymph and deutonymph stages and finally adult. From egg to adult takes 6-7 days for females and 5-6 for males.
Mites will pierce an opening in the prepupa honey bee larva and the whole family of mites will feed from that one wound. As the family grows and the bee emerges, the foundress mite will leave the cell with one or more new female daughters. The males die and never leave the cell and the bees clean them out. The adult females will then attach to adult bees for an average of 7 days before finding a new cell to enter and reproduce again. During her lifetime the foundress mite will go through 3 reproductive cycles.
IMPACT ON THE COLONY
The impact of varroa mites on a colony varies depending on the level of infestation and the level of diseases the mites may carry. Several mites in one cell can seriously cripple the developing bee, through the loss of blood, injury or spread of disease. Mites can also negatively impact adult bee. An adult bee can have trouble flying and Deformed Wing Viruscarrying out normal work when they have more than 2 mites on them at one time. Mites vector several diseases as they feed on bee hemolymph. A common disease that is spread is Deformed Wing Virus (DWV).  Bees with deformed wing virus are easy to identify and gives evidence to the high level of mite infestation in the hive. The wings appear burnt or deformed.
NATURAL TREAMENT
liquidnitrogenWe prefer not to use chemicals in treating for mites. Instead our first line of defense is raising queens that are VSH, Varroa Sensitive Hygienic. These bees detect mites below the sealed brood and remove the pupae and mites, taking them outside the hive. In the photo,  Liquid Nitrogen is used to kill a circle of brood and then it is measured in 24 hours to see how much of the dead brood was removed. This identifies a VSH trait in a colony.
GreendronecombThe next natural line of defense is trapping. Green drone comb can be placed in the hive. Since drones are the longest to develop, 24 days before they emerge, mites prefer drone cells so they have longer to try and reproduce more female mites. Once the drone comb frame is sealed, it can be removed and frozen for 24 hours killing all the mites, and drones too of course. Then, the comb can be placed back in the hive to be cleaned out by the bees and the process repeated.
The third level of natural defense against mites is the use of a screen bottom board. Since mites are parasites, they do lose their grip. Sometimes they are groomed off of bees by other bees and when they fall, they fall through the screen bottom board. It is effective, just observe the number of mites that fall through the screen. Once out of the hive, they do not move and therefore cannot feed and die below the hive. Not all mites will fall out of the hive, but those that do will decrease the colony’s mite load.
A fourth plan of attack is to treat the hive with powdered sugar or confectionery sugar. Shake one cup of powdered sugar per deep hive body. Let it fall between the frames. The powdered sugar causes the bees to groom mites off and some mites just lose their grip and fall. This should be repeated once a week for at least 3 weeks.
A final natural defense against mites is to break their own brood cycle. By pulling out the queen for 2 weeks, the mites cannot reproduce and are greatly reduced. The lack of bee brood removes the mite’s hosts.
CHEMICALS
More and more chemicals are available. Some chemicals in the past have show to have negative effects on the drones and queens reproductive organs. However, newer chemicals have shown to be more effective with less side effects. We recommend that you carefully research each chemical that is available and make your own decisions about using chemicals in your hives.
Now you probably know more about mites than you ever wanted to know, but keep this teaching handy because it can give you greater knowledge to help your bees not succumb to the mites.
These Words Might Be New To You…
Hemolymph  -  Bee blood
Exoskeleton – Bees have a hard outer covering rather than an internal
                     skeleton.
Ectoparasite – A parasite that lives on the outer surface.
Phoretic stage  -  Adult Varroa mite
Protonymph – A newly hatched mite
Deutonymph – The last stage prior to the adult stage.
Foundress – Female egg laying mite

TESTING FOR MITES
Some suggest placing a mite collection sheet, sticky board, beneath the screen bottom board for 1 day and then counting to see if more that 25 mites can be counted, exceeding the economic threshold requiring additional action or treatment.
However, I have found visually inspecting phoretic mites on adult bees and inspecting mites on drone purpae gives a better picture as to the extent of mite infestation. Obviously, we must also inspect the bees for mite damage or vectored diseases from mites that show up in the colony.

Thanks for joining us today and please check out our contact information and contact us soon! We’d love to hear from you:
Long Lane Honey Bee Farms
14556 N 1020 E Rd
Fairmount, IL 61841
217-427-2678

www.honeybeesonline.com
Until next time, Bee-Have Yourself!
David & Sheri Burns





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