A Potential New Acaricidal Compound for Varroa Mite Management

Thursday 14 March 2024

There is a global need for chemical treatments to manage the honey bee pest Varroa destructor. However, due to an over-reliance on some of these chemical treatments, especially synthetic products, miticide resistance has occurred with products such as Check Mite, Bayvarol and Apistan. Currently Apivar is the only recommended synthetic product for treating Varroa mites. This means there is a need for more product options so that beekeepers can alternate their chemical treatments, and potentially avoid miticide resistance. In today’s blog we will discuss a potential new acaracide, which has been studied by Dr. Steve Pernal (Agriculture and Agri-Food Canada) and Dr. Erika Plettner (Simon Fraser University).

A Potential New Acaricidal Compound for Varroa Mite Management

A project conducted in British Columbia and Alberta from 2019-2022 has determined that the compound 1-allyloxy-4propoxybenzene, also known as 3c{3, 6}, has strong acaricidal activity against Varroa destructor. Additionally, the project leads, Dr. Pernel and Dr. Plettner, determined the product has no appreciable toxicity towards bees. In 2023, the team generated additional data supporting the safety and efficacy of the product, with the intention of having the product registered in the future.

The compound 3c{3, 6} was first discovered to deter larval feeding in 2010 on a study involving the cabbage looper (Trichoplusia ni)1. In 2014, it was discovered that this compound can synergize with the active deterrent in neem, Azadirachtin A, with regard to larval feeding deterrence of T. ni2. More recently, in 2016, it was reported that 3c{3,6} repels malaria mosquitoes (Anopheles gambiae) with similar efficacy to DEET (N,N-diethyl-meta-toluamide)3. This led to another study to investigate if the compound would deter the Varroa mites’ ability to detect a honey bee host4. The study found that 3c{3,6} affects the ability of Varroa mites to detect and reach a honey bee host4, and following this field trials were conducted by Dr. Pernel and Dr. Plettner starting in 20195.

The effect of hexane control or 3c{3,6} treatment on the choice of Varroa mites between nurse and forager bees. Bars represent the percentage of mites selecting a nurse (white) or a forager (stippled) after 60, 120, and 180 min. (a) Control: hexane. (b) Treatment with compound 3c{3,6} at 10 μg in 1 μL hexane. From study by Singh et al. 2020.

In 2023, two field trials were conducted over differing time frames: one in Beaverlodge, AB during the spring, and the other in the lower mainland of BC during the late summer/fall5. Both experiments involved the same duration of treatment application (6 weeks) as well as the same amount of 3c{3,6} (10g) applied to honey bee colonies. There were twenty colonies used in each test location.

The treatment itself was delivered using a wooden applicator with 10g of 3c{3,6} dissolved in isopropanol with 2g of glycerol, administered using three treated wood slats hanging between brood frames5. In 2023, the amount of 3c{3,6} applied to colonies was increased from the 8g used in 2022.

At the start of the experiment the team performed an alcohol wash to establish phoretic mite loads on adult bees, and they examined 100 cells of capped brood to determine levels of mite reproduction. After the treatment period, a second alcohol wash was conducted to determine the efficacy of treatment. Each colony had a removable sticky board placed beneath a screened bottom board to collect falling mites, which were collected and counted throughout the experiment. Additionally, samples of honey and wax were drawn from brood chambers and supers to assess any potential 3c{3,6} residue risks.

The results of the 2023 field trials are not yet published. However, results to date indicate high efficacy of both spring and fall treatments of 3c{3,6}. In 2019, the field trials concluded that 3c{3,6} causes mortality of phoretic mites in bee colonies, as measured by the numbers of mites dropping onto sticky boards5. In 2019, the efficacy of this compound in the field was 51.2 ± 6.2% in BC and 81.1 ± 2.9% in AB5.


  1. Akhtar, Y., Yu, Y., Isman, M.B. and Plettner, E., 2010. Dialkoxybenzene and dialkoxyallylbenzene feeding and oviposition deterrents against the cabbage looper, Trichoplusia ni: potential insect behavior control agents. Journal of agricultural and food chemistry58(8), pp.4983-4991.
  2. Cameron, L.M., Rogers, M., Aalhus, M., Seward, B., Yu, Y. and Plettner, E., 2014. Feeding deterrence of cabbage looper (Lepidoptera: Noctuidae) by 1-allyloxy-4-propoxybenzene, alone and blended with neem extract. Journal of economic entomology, 107(6), pp.2119-2129.
  3. Hodson, C.N., Yu, Y., Plettner, E. and Roitberg, B.D., 2016. New repellent effective against African malaria mosquito Anopheles gambiae: implications for vector control. Medical and Veterinary Entomology, 30(4), pp.369-376.
  4. Singh, N.K., Eliash, N., Raj, S., Kim, J., Yu, Y., Plettner, E. and Soroker, V., 2020. Effect of the insect feeding deterrent 1-allyloxy-4-propoxybenzene on olfactory responses and host choice of Varroa destructor. Apidologie, 51, pp.1133-1142.
  5. Dawdani, S., O’Neill, M., Castillo, C., Sámano, J.E.M., Higo, H., Ibrahim, A., Pernal, S.F. and Plettner, E., 2023. Effects of dialkoxybenzenes against Varroa destructor and identification of 1-allyloxy-4-propoxybenzene as a promising acaricide candidate. Scientific Reports, 13(1), p.11195.

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