## 3 Results
### Section D: Antimicrobial Use for Varroa Control  
A similar percentage of the respondents from the Americas (81%) and Europe (80.4%) stated that they had treated colonies with medicines against varroa mites in the last 2 years. On the contrary, about 20% of the beekeepers did not treat their bees at all. Figure 2 shows the different approaches concerning the varroa treatments: soft acaricides [1] (thymol, oxalic acid, formic acid, hop acid, and lactic acid) and hard acaricides (Amitraz, Flumethrin, Tau Fluvalinate, and Coumaphos) administered alone or combined. Most of the beekeepers in both continents reported using mainly low-environmental-impact products (55.1% in the Americas and 53.1% in Europe) instead of high-environmental-impact products alone (3.4% in the Americas and 7.8% in Europe). A much lower percentage of beekeepers (17.7% in the Americas and 15.8% in Europe) used a mixture of the two types. \begin{table}
\begin{tabular}{c c c} \hline
**Hives Inspection** & **The Americas (\%)** & **Europe (\%)** \\ \hline More than four times a month & 4.1 & 13.1 \\ Four times a month & 21.8 & 38.9 \\ Two to three times a month & 51.7 & 36.8 \\ Once a month & 21.1 & 7.1 \\ Never & 1.4 & 4.2 \\ \hline \end{tabular}
\end{table} 
Table 1: Number of inspections during the active season both in the Americas and in Europe. The values are expressed in percent (%). Columns exceed 100% due to rounding. Figure 3 shows the name of the active ingredients used by the respondents during the previous year to treat varroa mites. The highest percentage of beekeepers in Europe (53.9%) reported using soft acaricidal products containing oxalic acid as the active ingredient, followed by those who used thymol (28.8%) and formic acid (27.2%). In the Americas, the highest percentage used formic acid (46.9%), oxalic acid (39.5%), and thymol (29.9%). Another difference in the use of low-environmental-impact products is that only American beekeepers (8.8%) use hop acids. Concerning the use of hard acaricides, instead, about the same percentage of both American and European beekeepers used Amitraz (about 20%), and a lower percentage in each continent used Flumenthrin (2%), followed by Tau Fluvalinate (5% in the Americas and 0.7% in Europe). Only 0.8% of the European beekeepers used Coumaphos (Figure 3). \begin{table}
\begin{tabular}{c c c c} \hline
**Varroa Prevention** & **The Americas** & **Europe** & **Relevance** \\
**and Control Measures** & & & \\ \hline Maintaining the number of varroa below the harmful threshold in each colony & 1.87 & 1.85 & \\ \hline Having good knowledge of the signs of varroosis and virosis & 1.67 * & 1.81 * & \\ \hline Treating swarms (no brood) just after harvest & - & 1.68 *** & \\ \hline Adopting diagnostic tools for measuring varroa infestation levels after & 1.72 ** & 1.55 ** & \\ treatments and during the year & & & \\ \hline Selecting and breeding queens that are more varroa tolerant/resistant & 1.57 & 1.48 & \\ \hline Treating swarms (no brood) just after harvest & 1.32 *** & - & \\ Nuclei and swarms should originate from colonies with no clinical signs of & 1.29 & 1.36 & Medium \\ diseases related with varroa & & & \\ \hline Adopting/providing hives with screened bottom boards & 1.00 *** & 1.35 *** & \\ \hline Providing sufficient number of healthy spare bees at the right time & 0.86 & 0.81 & Low \\ \hline \end{tabular}
\end{table} 
Table 2: Mean values of usefulness of varroa prevention and control measures both in the Americas and in Europe. Figure 2: Percentages of use of “Soft” and “Hard” acaricides from respondents both in the Americas and in Europe to treat varroa. With regard to the number of annually applied treatments for varroa control, a plurality of European (45.2%) and American beekeepers (49.7%) used more than one active ingredient, while a significant percentage of the beekeepers in Europe (31.6%) and in the Americas (26.5%) commonly used only one active ingredient.