Beyond the Hive

Oxalic Acid Fogging

Commercial beekeeping

This beekeeper discovered a Varroa infestation in his hives following which he decided to use oxalic acid fogging as his primary treatment. The beekeeper soon discovered this particular treatment used in this way did not deliver the results he expected.

Profile 

Name: Anonymous

Years in the Industry: 10 years

Number of Hives: 400

Operation type: Honey production and pollination 

Varroa Discovery

This beekeeper first discovered Varroa at the end of December 2024. When working his hives he came across a weaker hive and discovered it was overrun by mites. This was the first time the beekeeper had encountered mites and he found it quite distressing to have an infestation in his hives. 

Fogging as primary treatment 

After researching treatments the beekeeper decided to try oxalic acid fogging. He fogged his hives, waited 7 days then fogged them again. He did this twice. He placed sticky mats in the bottom of the hive to monitor results and got a big mite drop after the first round of fogging. But he also saw bee numbers decline.  

‘I was willing to take that loss if it worked as good as I thought it would.’

Although there was a mite drop this beekeeper found that the fogging was only killing mites on bees not in brood. Fogging again after 7 days he didn’t see a significant increase in mite numbers, however, numbers steadily increased over the following months when he used the treatment for a second time.  

The beekeeper soon discovered that this treatment was not giving him the results he had hoped for and the method is best used in colder conditions when the bees are broodless.  

Fogging should be used as a flash treatment even with brood present. The method can extend the time frame between other chemical use.  

Expectations 

The beekeeper chose to use fogging as their primary treatment due to the ease of use and seemingly great results after researching its use and effectiveness overseas. After trialling the treatment he discovered it wasn’t as effective as he thought it would be.  

He had wall to wall brood so the fogging couldn’t reach mites within the brood and he found that he was losing too many bees to the treatment.  

‘In peak times when I’ve got wall to wall brood fogging hasn’t been as effective as I would like’. 

Looking to the future 

This beekeeper is feeling positive about his future in beekeeping. 

‘It’s not all doom and gloom. If you’re willing to do the work I don’t see anything changing.’