PDA

View Full Version : Science and rational Varroa control



fatshark
26-03-2018, 08:54 PM
It's a bit quiet here, but I'll use this as an opportunity to mention a talk I'm giving tomorrow night (http://peeblesbeekeepers.org.uk/?p=1076) - 27th March - at Peeblesshire BKA, 7.30pm Drill Hall, Walkersheugh, Peebles on rational Varroa control and how science can help.

busybeephilip
23-04-2018, 10:12 PM
Did you mention Lithium Chloride - new varroa wonder drug ?

fatshark
24-04-2018, 08:46 AM
No ... and it's not ;) It's an observation made from a negative control during a different attempt to control Varroa. Time will tell whether it becomes the new wonder drug, but there's a helluva way to go.

We've got pretty good treatments already ... if they were used properly. They're often not.

Thymallus
25-04-2018, 08:46 AM
Did you mention Lithium Chloride - new varroa wonder drug ?

I hear it may kill larvae.....all the work I can find has been done with individual bees or swarms or brood-less bees. Me wonders why!

busybeephilip
25-04-2018, 05:13 PM
We may wait and see what happens, i'm sure its being investigated as we ..type.. Meanwhile bet you see the price of LiCl, something very cheap, rocketing in price.

By the way, perhaps of interest to followers of Randy Oliver's oxalic acid towels, tried this - conclusion it seems to work during the summer months in strong colonies but autumn and winter/spring forget it as I have learn't from loosing many boxes treated this way - back to vaping and strips.

mbc
25-04-2018, 07:55 PM
By the way, perhaps of interest to followers of Randy Oliver's oxalic acid towels, tried this - conclusion it seems to work during the summer months in strong colonies but autumn and winter/spring forget it as I have learn't from loosing many boxes treated this way - back to vaping and strips.

Laying towels over the top bars of single brood box colonies has not really touched the blighters for me either, but hanging cardboard strips (I've been trying different types and have settled on cut up cereal packets as seeming to do the trick) on frames bordering the nest as the colony expands in the spring seems to be very effective, most of the strips are chewed up in two to three weeks in my experience and I've struggled to find varroa afterwards, by drone fork or the shaky pot thing, apart from one or two colonies which for some reason I cannot fathom the varroa has still got hold.

Thymallus
27-04-2018, 12:04 PM
We may wait and see what happens, i'm sure its being investigated as we ..type.. Meanwhile bet you see the price of LiCl, something very cheap, rocketing in price.

The lethal effects on larvae are not in the the original paper but are described in the patent application. (https://patents.google.com/patent/WO2017042240A1/en) Essentially LiCl, as applied in their experimental paradigm is kills bee larvae with 3 days.
I quote from the patent.
"In order to assess the effect of LiCl on larval development in vitro, larvae were obtained by caging the queen for 24 h on broodless combs in the colony. After 5 to 6 days when the larvae reached the age of about 48 h they were transferred to petri dishes filled with larval food. The petri dishes were placed in plastic boxed filled with 8 % sulfuric acid in order to prevent fungi infection and kept in a chamber at 34C and 95% relative humidity. The larvae were fed as needed with a mixture consisting of 53% royal jelly, 4% glucose, 8 % fructose, 1% yeast extract and water (control). For samples treated with LiCl, 10 mM, 25 mM or 50 mM LiCl were added to the mixture. Prior to the pupa phase, the larvae were placed on a tissue for defecating which occurred approximately on day 9. Afterwards larvae were placed in well plates until hatching. Larvae mortality was monitored on a daily basis.

Table 5 summarizes the results expressed as survival rate of larvae or pupae. All larvae were lost within 72 hours implicating a strong lethal effect of LiCl on larvae. Since 25 mM LiCl is tolerated by bees very well but larvae viability is crucially impacted already at 10 mM LiCl, it follows that LiCl should ideally be applied when egg laying is decreased. Such a phase naturally occurs between the calender start of summer6 and the overwintering period.

Paul_
30-04-2018, 10:07 AM
I've been putting lithium batteries in my hives, was that a waste of time?

Seriously, I started doing alcohol washes two seasons ago and it revolutionised how I look after mites. I've bought one of those easy check devices at the honey show last year, so hopefully, it'll be less messy now.

Has anyone used Randy Olivers mite model spreadsheet - http://scientificbeekeeping.com/randys-varroa-model/ - I'm going to give it a whirl this season.

Adam
08-05-2018, 05:06 PM
I tend to miss threads down the main page - or under 'Local Associations' in this case...

What's best method for checking for mites; alcohol wash or sugar shake?

Paul_
08-05-2018, 06:03 PM
I tend to miss threads down the main page - or under 'Local Associations' in this case...

What's best method for checking for mites; alcohol wash or sugar shake?

This is a good summary of the various methods: http://scientificbeekeeping.com/sick-bees-part-11-mite-monitoring-methods/

I use the alcohol because it's just easier for me - although it smells alot when you poor it in your bee tool bag by mistake

Greengage
17-05-2018, 07:35 AM
nice link tks