## 3 Results  
Tables 1 and 2 summarize the main results of the reporting and analytical activities carried out from 2015 to 2020, following the introduction of the Ministerial Guidelines of 31 July 2014 for the management of honey bee-killing incidents relating to honey bees and other matrices, respectively. As shown in Table 1, the pyrethroid tau-fluvalinate is certainly the most commonly found substance, followed by chlorpyrifos (referred to as chlorpyrifos-ethyl), chlorpyrifos-methyl (both organophosphates), and piperonyl butoxide (a synergism component of pesticide formulations). The active substances were detected in a wide range of concentrations. Observing the results in Table 1, we see that a potentially dangerous concentration, not only for honey bees, was detected for one active substance only, namely, permethrin, a pyrethroid found in a sample of dead bees in 2016 at a concentration of 1346.65 mg/kg, i.e., about six times its oral LD50 value (c220 mg/kg). In 2020 a significant concentration, albeit lower than the LD50 value, was again detected, as were residues of metonyml (a carbamate) in 2017 (7.65 mg/kg) and cypermethrin (a pyrethroid) in 2015 (76.02 mg/kg). Table 2 reports the results of the other matrices linked to honey bee-killing incidents received at our laboratory. Other matrices were usually honeycombs, pollen, honey, vegetable materials (leaves, flowers, corn seedlings, maize), and other samples, including liquid dripping from the bottom board, suspected material collected on propolisis, and hive debris. Again, tau-fluvalinate was the most frequently detected active substance, followed by coumaphos (an organophosphate). In general, the detected concentrations were much lower than the LD50 values, with the exception, in 2018, of a vegetable matrix sample (leaves) found to be positive for methiocarb (a carbamate) at a concentration of 70.65 mg/kg (oral LD50 20 mg/kg) and, in 2020, of a sample of a suspect material deposited on propolisis inside the beehive, testing positive for cypermethrin at a concentration of 569.91 mg/kg, \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Year**} & **No. of** & **Positive** & **No. ASs** & **Most Frequent ASs** & **Range** & **Oral LD50** & **Most Concentrated** \\  & **Samples** & **Matrix** & **(\%)** & **Identified** & **(Prevalence \%)** & **(mg/kg)** & **(mg/kg)** & **AS** \\ \hline
2017 & 23 & & 57 & 10 & tau-fluvalinate (31) & 0.010–4.59 & \(>\)3000 & tau-fluvalinate 4.59 \\  & 11 & comb & 91 & 9 & chlorpyrifos (23) & 0.011–0.10 & 135 & \\  & 7 & pollen & 43 & 3 & tau-fluvalinate (60) & 0.17–4.59 & \(>\)3000 & \\  & 5 & honey & 0 & 0 & - & & & \\ \hline
2018 & 36 & & 83 & 26 & tau- & 0.031– & \(>\)3000/20 & folpet 511.10 \\  & & & & & (50) & 1.91/0.010–70.65 & \(>\)3000/20 & (LD50 \(>\) 10,000) \\  & & & & & & cournambos (27) & 0.011–0.72 & 7.1 & \\  & 11 & comb & 91 & 10 & tau-fluvalinate (100) & 0.031–1.91 & \(>\)3000 & \\  & 10 & pollen & 90 & 14 & tau-fluvalinate (67) & 0.034–0.68 & \(>\)3000 & \\  & 7 & honey & 71 & 1 & methiocarb (100) & 0.011–0.68 & 20 & \\  & 8 & vegetable & 75 & 12 & delathemrth (67) & 0.046–0.12 & c135 & \\ \hline
2019 & 73 & & 56 & 27 & tau-fluvalinate (58) & 0.017–95.90 & \(>\)3000 & tau-fluvalinate 95.90 \\  & 32 & comb & 78 & 16 & tau-fluvalinate (68) & 0.017–0.40 & \(>\)3000 & \\  & 14 & pollen & 78 & 11 & fluvalinate/pyrimethanil (Z7) & 34.20– & \(>\)3000/4150 & \\  & 25 & honey & 12 & 2 & tau-fluvalinate (67) & 0.029–0.048 & \(>\)3000 & \\  & 2 & vegetable & 100 & 6 & - & & & \\ \hline
2020 & 79 & & 60 & 37 & tau-fluvalinate (69) & 0.013–3.93 & \(>\)3000 & cypermethrin 569.91 \\  & & & & & cournambos (31) & 0.013–0.65 & 7.1 & \\  & 48 & comb & 71 & 24 & tau-fluvalinate (82) & 0.013–3.93 & \(>\)3000 & \\  & 8 & pollen & 25 & 6 & - & & \\  & 5 & honey & 0 & 0 & - & & \\  & 15 & vegetable & 60 & 17 & - & & \\  & 3 & other * & 67 & 5 & - & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: \(Cont.\)i.e., more than twice its oral LD50 value (c250 mg/kg).