• Nick Taylor

Set up to Succeed with Your Varroa Treatments – Tips from a Supplier


By Nick Taylor, general manager New Zealand Beeswax

If you are feeling like varroa is getting a little bit tougher to manage every year, you are not alone. The number one question we were asked at Apiculture New Zealand’s conference this year was, ‘it’s tough out there, what’s the winning recipe?’.

Both New Zealand Beeswax and the wider industry response has been ultra-consistent for the last 20 years in NZ: The core treatments in spring and autumn are the most critical; full dose; full treatment period; alternate chemical class; monitor. Despite two decades of this mantra, the majority of NZ beekeepers are wilfully deviating from the basics.

Nick Taylor

The Colony Loss Survey in 2021 clearly highlights this variation in decision making. Some of the lowlights include:

· About a half of flumethrin (Bayvarol) users don’t apply the recommended 4 strips per brood box, and about half don’t keep them in for the full 8-week treatment period.

· While amitraz based products (e.g. Apivar) are registered for 6 to 10 weeks, less than 15% of users treat for 10 weeks. The expression ‘set up to succeed vs set up to fail’ comes to mind.

· Despite the above, 84.4% of survey respondents deemed their flumethrin (Bayvarol) treatment completely or mostly a success and 88% for amitraz (e.g. Apivar).

There are 100 different variables that contribute to fluctuating varroa levels in any given season/year. While it is important to be cognisant of these potential variables, it shouldn’t distract from your own decision making. Remember ‘control what you can control’, that being: monitoring, timing, treatment choice, dose, duration and alternating treatments. Choose setting up to succeed.

All varroa treatments in New Zealand (and globally) have the same weakness: the higher the mite load going into the treatment, likely the higher mite load coming out the other end.

What are the treatment trends that are working more consistently across the motu?

1) Get the core sorted. That’s ‘1st tier’ treatments such as Apivar and Bayvarol.

2) Varroa management is a 12-month task, utilise suppression tools with the goal of slowing varroa build-up. That’s incorporating ‘3rd tier’ treatments in-between spring/autumn. The days of only two treatments a year, set to the calendar, resulting in consistent success, are all but gone (with the exception of a few remote/neighbour-less pockets).

Not all New Zealand beekeepers are using the common varroa treatments as effectively as possible and there are some simple improvements that should be made, says NZ Beeswax’s Nick Taylor.

‘3rd Tier’ Options

There are a wide range of varroa suppression options, all candidly come with their own unique pros and cons. Some being: low treatment cost but high labour/travel cost, hard on both the mites and the bees, variability in efficacy, temperature constraints, hard on bee gut health etc.

Ultimately each beekeeper needs to weigh up these pros and cons, and how to integrate one or more of these into their operation. Options include

· adding another traditional strip treatment

· Formic acid (e.g. Formic Pro)

· Oxalic acid (vaporising, with glycerine, or trickle method)

· Thymol

Seek advice from your fellow beekeepers and/or a trusted supply company, take that advice with a pinch of salt and remember none of the ‘cons’ are as bad for the bees as doing nothing at all – something Dr Jamie Ellis stressed while presenting at the ApiNZ conference recently.

Miticide sales over the past 10 years show they are being used earlier and earlier in both spring and autumn.

Whatever you do – Time it Right

Timing is an important factor in success, with 20 years of experience distributing varroa treatments, we have observed the steady shift towards treating earlier and earlier.

Using the last 10 years of Apivar sales as the benchmark, peak spring sales were once mid-September, but that is now six weeks sooner in early-August. We’ve seen the same trend in autumn, with the peak 10 years ago in March now moved to the last week of January or first week of February.

Something Else to Consider…

The rapid colony growth in spring hides a multitude of sins. It’s the autumn switch that is most likely to reveal issues. The snowball effect of 12 months decision making (and a multitude of variables) rolls towards the autumn and the exponential wave of mites overwhelms the tapering population of adult bees.

This can hit like a light switch. I’ve lost count of the times I’ve heard ‘they looked good two weeks ago, but…’. The most common solution offered by beekeepers is to use a quality treatment asap after honey supers come off, and utilise a suppression tool during the summer to minimise the build-up in the first place.

One More Tip

Here’s a simple tip to boost your strip treatment efficacy… Let’s get back to the basics: the leading strip treatments work by contact only. The more bees that get in contact with the strips, the more active ingredient they will collect from the surface. That is why the strips always need to be placed in the centre of the brood: this is where we can observe the highest activity in the hive, resulting in the highest number of potential contacts, and it’s also here that varroa mites will emerge from the brood cells.

During a long action treatment e.g. 6-10 weeks for Apivar and 8 weeks for Bayvarol, it is not rare to see the strips covered by wax and propolis after several weeks. However, the propolis/wax will decrease the accessible surface on the strips for bees and therefore reduce the number of potential contacts. Moreover, after a few weeks, the bees’ cluster may have moved within the brood box. Thus, during your site visits, we advise scraping the strips systematically at mid-treatment (with a hive-tool) and repositioning them in the centre of the bee cluster.

Don’t just take my word for it… in France a study (by ADAPI, the French Association for the Development of Beekeeping) found this simple habit of cleaning and repositioning strips resulted in a 1 to 4% improvement in treatment efficacy. Any varroa mite modelling will tell you, the hive health and honey production gains resulting from a 99% vs 95% efficacy result, is well worth achieving.