Randy’s Varroa Model

I feel that our industry and research community has long needed a useful, accurate, and user-friendly varroa population model–so I spent a year of early mornings and weekends creating this one.  You can use this model to predict what sort of mite management strategy will work in your area.

I’m currently revising this page to insert an interactive model. 

You have four options for using the model:

Option #1:  If you have Excel installed on your computer, download the current version Randys-Varroa-Model-V2024A (I frequently update the link, so always download the current one).

Option #2:  If you don’t have Excel, you can open an interactive web version by going down to the  embedded version in Option #3, and click on the double-rectangle icon in the right corner of the dark bar at the bottom (as indicated in the image below) — it will open a new tab in your browser.  You may need to first install the trial version of Excel (click here).

Once the tab opens, you’ll need to click on the green viewing tab and on “editing” (or the “enable editing” tab.

Option #3:  If neither of the above work, you can use the embedded interactive version below on this webpage, but you will need to do more scrolling (swipe with two fingers or the scrollbar to the right to see the mite treatments, etc), and you will need to type in a zero to delete any inputted treatments (or reload this page).

For Joe Beekeeper, the model is easy to use –read the instructions at the top of the chart.  You simply type inputs into the three green cells to the left to see whether your colony is likely to crash.  In order to avoid such a crash, you can then apply one or more “treatments” (percent mite reductions) on any date in the yellow cells below the graph–each time you click on another cell or hit “enter,” the model instantly runs a new simulation.  By this method, you can test various mite management strategies at your computer.

Note:  In this imbedded model, you can’t delete a mite treatment number in the yellow cells, so to delete an entered treatment,  just click on the cell and enter “0” (zero);  or simply reload the page to go back to the beginning. (Addional instructions for use are further below).  Have fun!

Option #4:  Alternatively, Trish Harness has a simplified online model that you can use on your cell phone at https://www.chickabuzz.com/model.html   (she worked hard to create this, so please donate to her).

Printable Basic Instructions

Once you open the workbook in Excel, click “enable editing.”

In order to prevent inadvertent changes to the wrong cells, I’ve locked all the cells other than those ready for user inputs (the yellow cells).

Then go to the bottom right corner of the window and set to 90% view, then to the “View” tab at the top, and hit “Full Screen” (hit “Escape” on your keyboard if at any time you wish to exit Full Screen view).

I suggest that you first open the “Necessary mite reduction” tab at the bottom to get an idea of the basic concept.  Type in various numbers of months with brood, and different treatment percentages in order to understand how much varroa control you will need for your region.

After you’ve got the concept, then switch over to the “Current Version” tab to use the model itself.

All the instructions that most beekeepers will need are under the “Instructions” on rows 26-34.  There aren’t very many instructions, so please read these first!

I suggest starting with the Default “Colony” (type “d” into cell B29, “100” mites in B31, and “1” for immigration in B33.  If you keep bees in the Southern Hemisphere, type an “x” into P27.

After you’ve played with the Default colony by entering mite treatments, then you’ll want to go to the “Colony” tab, and either choose a colony type for your area, or create your own colony profile (please send me any accurate regional colony profiles, so that I can post them).  View Tutorial #3 before attempting to create your colony!

Those with greater interest can go down to the green cells in the “Advanced” section of the Current Version tab, and type in the word “custom” to investigate the effects of changing key parameters involved in mite population buildup.

Have fun!

Randy