Randy: said:

Medhat has developed a vaporizer that uses forced air to open the cluster 
so
that the vapors can penetrate.  He has much more data of efficacy of OA
vapor.

The evaporizer that was developed was originally done by Cor DeWit. 
However, beekeepers did not like the size of the machine,specially 
bringing it to the field and moving around the bee yard. I worked with Cor 
to upgrade the system to make it portable, optimized and efficient. Thus, 
the machine can be used as a single, double or 4 unites. This design gives 
flexibility for beekeepers to buy a unit that suit the # of bee hives. one 
unit can be good for 200 or less hives operation. 2 units for 50 hives' 
operation 4 unites for 1000 hives' operation.
Treatment time is 60-90 sec not 20 sec. This is not a buff of cigarette. 
let us be real. A yard of 40 hives takes 30-40 min when you use 4 units 
applicator.

Efficacy was 93%+/- 3% when little brood or no brood by mid Nov. in 
Alberta.
Efficacy in early October was 65% +/- 17%  due to brood presence.
ambient temperature is no longer a factor in determining efficacy as for 
other applicators. The OA vapor delivered onto the hive is about 20C. This 
helps to break the cluster and give better exposure of bees and varroa to 
OA.

You can treat two times in October and mid Nov, efficacy can be >95%.
The important question is protecting winter bees. If Varroa mites are too 
high (>10%) in August-September winter bees will be damaged from varroa 
before even treatment. Therefore, beekeepers should be monitoring their 
mites and make proper decision and use the proper options for varroa 
treatment.



Medhat
 
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]

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