Just a recap of this most interesting problem submitted by a BEE-L lurker...

> I have been using the Jenter kit to obtain larvae of the correct age and
> then use a modified swarm box as a starter for 24 hours after which the
> cells are transferred to the second hive body above an excluder for
> finishing. I've been getting excellent queens that are well adapted to my
> area's harsh conditions and my question is why am I getting a higher than
> normal percentage of dud cells this year. The cells look good when
> transferring them to the finisher and also when counting them on the 4th
> day
> after transfer but when they are harvested, I find up to 20% are not
> viable.
> These cells are capped over and have a brownish tip but otherwise look
> normal. I hold them up to the sunlight and if I cannot see a pupae I cull
> them and open them up to find an off white larvae turning to brown. The
> mess
> does not string out and if left long enough it turns rubbery. If I miss
> one,
> I find it in the nuc when checking mating and It has not been torn down

At the same time I wrote to BEE-L recently, I wrote to Medhat.  Here's his
reply:

--- Medhat's reply ---

Regarding your queen cells loss. There is one or two situations:

1. queen cells on the edges of the bars in the queen cell finisher could be
chilled at night when the temperature gets cold and the bee cluster shrinks.
In this case the brown dried larvae/ pupae could be formed. To cure this
case, you need to strengthen your cell builders and keep the cells away from
the edge of the bars. May be start cells about 1.5"-2.0" from the edge.

2. In case of using Jenter kit, sometimes black queen cell virus will infect
the cells. This virus has tendency to show up when you keep repeating using
the same kit and sanitation conditions are not good. Once the virus infects
the queen cells, the queen larvae/pupae will die out and turn to charcoal
like colour. I would suggest clean up the Jenter kit and you might need to
use Clorox  1% to wash the kit. Make sure that you rinse the kit well with
water. Then, place the kit in the cell builder for the bees to clean it up
again. We found feeding the cell builders with Fumagillin would also help to
suppress the queen cell virus.

Medhat

P.S. Al, you can put this response on Bee-L if you wish

Medhat Nasr, Ph. D.
Provincial Apiculturist
Crop Diversification Centre North

17507 Fort Road
Edmonton, AB, Canada T5Y 6H3
Tel: (780) 415-2314    Fax: (780) 422-6096
Mailto:[log in to unmask]

-- Visit www.honeybeeworld.com/bee-l for rules, FAQ and  other info ---