The following is directly from my notes taken at the meeting. I have done my best to be accurate in recording but I must warn you that my notes may not be 100% accurate. Therefore any errors or omissions are my own and not the speakers’.
OBA Summer Beekeepers’ Meeting 12 July 2008
(photos courtesy of Mark Lauterbach)
Winter losses of honey bees in 2007 were reported at 37%. This is three times more than the expected rate of approximately 12%.
This represents 28,000 dead colonies and 3,300 lbs of honey lost, thousands of tons of crops not pollinated, representing approximately 50 million in losses.
Causes for the losses are attributed to Parasitic mites, viruses, IAPV (Israeli Acute Paralysis Virus) in particular, microsporidians, internal parasites Nosema apis and Nosema cerane, stress, malnutrition, and pesticides to control diseases (which are absorbed in the wax) and climate change. Losses are also attributed to inadequate management practices in the fall which is a critical time to treat hives. Colonies that are weak in the fall do not survive the winter.
184 beekeepers participated in their study, representing 27,669 colonies of bees. Of those in the study 9.081 colonies died, equaling a 32.8% mortality rate.
They monitored 413 colonies in the province of Ontario last fall (2007) and weighed hives, examined reserves and the number of frames per hive covered in bees and workers were sampled for levels of mites.
Of these 413 samples in the fall of 2007, 27% were dead in the spring of 2008. They found there were mites on adult bees.
There is a natural decline of Varroa Mites in the spring because colonies had no brood being raised where the Varroa mite breeds.
In studying samples of bees, they found up to 3 million Nosema spores in bees in the spring. This level has proven to be the maximum tolerable amount and these hives died.
Tracheal Mites – 5% in the fall which increased to 7% in the spring.
Hives that weighed 33 kilos in the fall died in the spring. Hives that weighed 35 kilos in the fall were still alive in spring.
Treat in the fall and spring, fumigate equipment and combs with acidic acid. (The Nosema spores in the combs are causing infection in the nurse bees).
How much chemicals remain in the wax is unknown and how much it is affecting bees is unknown. There are Penn State studies underway on this. Honey is hydrophilic – so chemicals would tend to be more in honey than wax (this would be the honey the bees eat in the deeps since chemicals are not used on hives when honey supers are on the hives).
It takes 5 micrograms to kill a bee with nicotinoid.
Beekeepers should be sure to monitor after treatment of mites to see if the treatment was effective.
One third of the bees in Ontario died in 2007/2008 which was similar to the year before.
Dr. Yanping (Judy) Chen from Beltsville, MD
There are two modes of transmission – Horizontal and Vertical. Horizontal transmission is food borne, through honey, pollen or feces. Horizontal transmission is through food, Varroa Mite vector and Mom to tot vertical transmission.
Six viruses have been detected in pollen: ABPV (900bp), BQCV (700), CBPV (455), DWV (702), KSV (417), SBV (2??)
The digestive tract of the queen and feces were exampled. BQCV and DWV were found in queen feces.
Virus transmission when mating – venereal disease, VM vector to transmit viruses.
KBV most prevalent using Varroa Mites as a vector. Virus also transmitting mite to mite.
Virus on surface – bleach wash – detected ovarian transmission.
USA CCD in 2006/2007: Disappearances in hives resulted in 50% losses of colonies. There was an absence of adult bees, capped brood and stored food. The hives had been abandoned. The collapsing hives had a lowered work force to carry on the hive.
Suspects are poor nutrition, pesticides, pathogens, lack of genetic diversity, and parasites such as Varroa Mites.
A micodial study found a correlation of IAPV which had not been reported in the USA previously). This virus was introduced to the USA from Australian imports of bees to the USA. Bee samples in the USA 2002/2003 have found that IAPV has been in the USA for a while, before the Australian imports. IAPV has a different evoluntionary rate in USA than in Isreal.
Multiple viruses, yet there are no treatments for viruses.
The completion of the honey bee genome will contribute to finding solutions. There is a vaccination for viruses for humans but not for bees.
They are working on a study to see if mites are transmitting IAPV.
It is difficult to determine the difference between viruses when dealing with multi viruses.
Spring 2008 Nosema Survey:
2006/2007 bee losses were 37% and in 2007/2008 they were 32%.
It was found that hive top feeders were much more efficient at distributing treatments to hives (increasing survival rates) than barrel feeding.
The Tech Team used a bee vacumm to collect older bees (field bees) and stored them in ethanol. They had 948 samples, did 67 operations covering 23 counties in Ontario. They counted Nosema spores. They crushed the samples and counted them with a microscope with a counting grid.
All the counties tested (Bruce, Dufferin, Elgin, Essex, Hamilton-Wentworth, Lambton, Middlesex, Niagara, Norfolk, Ottawa, Oxford and Wellington) were found to have Nosema cerane.
343 samples had Nosema cerane of the 948 collected, representing 36%. 231 samples were found to have more than 1 million spores per bee, representing 67% with over 1 million spores. The level of concern is 1 million spores.
529 colonies were barrel fed in 2007 - 0 to 40,350,000 spores
1,346,503 was the average spore count in spring samples. These bees were medicated and fed in the fall with fumigulin B.
How the fumigulin B is put in the barrel varied considerably between beekeepers. Hobby beekeepers (treated and fed) they had 64 samples that showed 0 to 3,775,000 spores. Non treated hived, 219 samples showed 1 to 30,550,000 spores.
Nosema Spore Counts:
Treatment Samples Spore Count
Barrel 529 40,350
Hive Top 64 3,775
Not Treated 219 30,550
Spore Count 3,385,274
Barrel fed bees were also moved a lot.
Bee Yard Stats:
Weak 2,825,000 1,250,000
Average 2,325,000 1,395,000
Strong 7,275,000 3,890,000
It was noted that a strong bee yard was not necessarily disease free. They noted that if hive spore counts showed on YOUNG bees then the hive was about to crash.
Three barrel fed bee yards were examined:
1 Fall 2007/2008 Spring 1,250,000 spores
2 Fall 2007/2008 Spring 110,000 spores
3 Fall 2007 No Spring Treatment 2,100,000 spores
Fumigilin spring treatment is important and beekeepers need to monitor spore levels.
Barrel feeding issues: Sunlight degrades the medication, mixing – when to mix; the medication settles to the bottom; it degrades over time; the timing of the treatment.
Resistance management – DO NOT DOUBLE DOSE!
Hive top feeding is better for treatements and has been put into the provincial recommendations for beekeepers.
Nosema apis & Nosema ceranae Indicators
Nosema is a silent killer.
Slow spring build up, disjointed wings, bloated belly, yellow steaks on hive, walking bees
It is a single cell parasite fungae microspirialia
The bees ingest spore matter through their food and water. They collected Nosema ceranae from many USA states. 16% infection of bees. Nosema ceranae is not new, it transferred from Asian honey bees to US honey bees.
The Nosema ceranae spore is smaller than the Nosema apis spore.
Polar filament coils 18 to 21 in Nosema ceranae. Nosema apis has 30.
Nosema ceranae was in all tissue of tested bees, except the muscles. Not much in the bee’s fat.
Nosema ceranae spores are extruded in feces and it was detected in their hypophynearl and salivary glands – so it is transmitted to the queen in feeding.
Nosema apis indicators are crawling and dysentery, and a milky coloured gut. These are not the indicators of Nosema ceranae.
Ribosomal RNA genome info – comparison between Nosema ceranae. and Nosema apis. Difference between the two spores is 92.7 – 2 extra roots in Nosema ceranae. Nosema ceranae and Nosema apis are not closely related. Nosema ceranae is closer to a wasp parasite. The host has jumped from the Asian bee to European bees.
They have sequenced the full genome of Nosema ceranae. It is noted that Nosema ceranae and Nosema apis compete for the same niche on their host.