Killer disease striking down Honey bees in US

 

By Bernie Mitchell

4 April 2007 -- Pick whichever name you like but at the end of the day honey bees are dying out at a horrendously fast rate in the US.

While it's been called Fall Dwindle Disease by some, others are referring to it as Colony Collapse Disorder (CCD). The essential point is that in 24 US states bees are dying.

CCD is the latest, and most serious, die-off of honey bee colonies across the US. It is characterized by, sudden colony death with a lack of adult bees in front of the dead-outs. Honey and bee bread are usually present and there is often evidence of recent brood rearing.

In some cases, the queen and a small number of survivor bees may be present in the brood nest. It is also characterized by delayed robbing and slower than normal invasion by common pests such as wax moth and small hive beetles.

This phenomenon first became apparent among commercial migratory beekeepers along the East Coast during the last few months of 2006 and has since been reported nationwide.

Importance of Honey Bee Pollination

Honey bees (genus Apis) are the most economically valuable pollinators of agricultural crops worldwide. In the US, bee pollination of agricultural crops is said to account for about one-third of the US diet, and contribute to the production of a wide range of fruits, vegetables, tree nuts, forage crops, some field crops, and other specialty crops.

The monetary value of honey bees as commercial pollinators in the United States is estimated at about $15 billion annually. This estimated value is measured according to the additional value of production attributable to honey bees, in terms of the value of the increased yield and quality achieved from honey bee pollination, including the indirect benefits of bee pollination required for seed production of some crops.

About one-third of the estimated value of commercial honey bee pollination is in alfalfa production, mostly for alfalfa hay. Another nearly 10% of the value of honey bee pollination is for apples, followed by 6-7% of the value each for almonds, citrus, cotton, and soybeans.

A number of agricultural crops are almost totally dependent on honey bee pollination (90-100%), including almonds, apples, avocados, blueberries, cranberries, cherries, kiwifruit, macadamia nuts, asparagus, broccoli, carrots, cauliflower, celery, cucumbers, onions, legume seeds, pumpkins, squash, and sunflowers. Other specialty crops also rely on honey bee pollination, but to a lesser degree. These crops include apricot, citrus (oranges, lemons, limes, grapefruit, tangerines, etc), peaches, pears, nectarines, plums, grapes, brambleberries, strawberries, olives, melon (cantaloupe, watermelon, and honeydew), peanuts, cotton, soybeans, and sugarbeets.

Another study found that pollinators are essential for the production of some US-grown crops, particularly macadamia nuts, squash, and pumpkins.

In the United States, most pollination services are provided by commercial migratory beekeepers who travel from state to state and provide pollination services to crop producers. These operations are able to supply a large number of bee colonies during the critical phase of a crop's bloom cycle, when honey bees pollinate a crop as they fly from flower to flower collecting nectar and pollen, which they carry back to the nest.

Each year, an estimated more than 2 million bee colonies are rented for US crop pollination. Available limited information indicates that the greatest number of honey bee colony rentals are for apple and almond production, followed by clover seed, cherries, and pears.

About the disease

The current phenomenon was first called "Fall-Dwindle Disease," but has been renamed CCD because of the unusual characteristics of the honey bee colony declines. First, the condition is not only seasonal but manifests itself throughout the year. Second, the term "dwindle" implies a gradual loss; CCD onset is sudden. Third, the term "disappearance" has been used to describe other types of conditions, which differ from the symptoms currently being associated with CCD. Finally, the term "disease" is usually associated with a biological agent but none has yet been identified.

The first report of CCD was in mid-November 2006 by a Pennsylvania beekeeper overwintering in Florida. By February 2007, large commercial migratory beekeepers in several states reported heavy losses associated with CCD. Reports of losses vary widely, ranging from losses of 30-90% of their bee colonies; some beekeepers fear loss of nearly all of their colonies in some cases. Surviving colonies are reportedly weakened and may no longer be viable to pollinate or produce honey.

Honey bee colony losses also have been reported in Canada and Europe.

Symptoms of Colony Collapse Disorder

One of the key symptoms of CCD in collapsed colonies is that the adult population is suddenly gone without any accumulation of dead bees.

The bees are not returning to the hive but are leaving behind their brood (young bees), their queen, and maybe a small cluster of adults. What is uncharacteristic about this situation is that the honey bee is a very social and colony-oriented insect.