# Surface Application of Different Insecticides Against Two Coleopteran Pests of Stored Products
## 4 Discussion
\begin{table}
\begin{tabular}{l l l l l l} \hline
**Days** & **Surface Type** & **Control** & **Alpha-** & **Primiphos-** & **Spinosad** \\  & & & **Cypermethrin** & **Methyl** & **Spinosad** \\ \hline
3 & Test-statistic & 5.38 & - & 16.17 & 12.09 \\  & \(p\) & 0.146 & - & \textless{}0.001 & 0.007 \\ \hline  & Concrete & 7.5 \(\pm\) 3.3 a & 100.0 \(\pm\) 0.0 & 98.3 \(\pm\) 1.0 & 100.0 \(\pm\) 0.0 \\  & Metallic & 30.8 \(\pm\) 7.2 b & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 99.1 \(\pm\) 0.8 \\
7 & Plastic & 3.3 \(\pm\) 1.6 a & 100.0 \(\pm\) 0.0 & 98.3 \(\pm\) 1.6 & 100.0 \(\pm\) 0.0 \\  & Ceramic & 22.5 \(\pm\) 3.3 b & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 97.5 \(\pm\) 2.5 \\  & Test-statistic & 16.27 & - & 3.77 & 2.09 \\  & \(p\) & 0.001 & - & 0.286 & 0.553 \\ \hline  & Concrete & 85.8 \(\pm\) 2.3 a & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 \\  & Metallic & 96.6 \(\pm\) 1.6 b & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 \\
14 & Plastic & 71.6 \(\pm\) 5.1 a & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 \\  & Ceramic & 100.0 \(\pm\) 0.0 b & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 \\  & Test-statistic & 18.59 & - & - & - \\  & \(p\) & \textless{}0.001 & - & - & - \\ \hline  & Concrete & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 \\  & Metallic & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 \\
21 & Plastic & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 \\  & Ceramic & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 & 100.0 \(\pm\) 0.0 \\  & Test-statistic & - & - & - & - \\  & \(p\) & - & - & - & - \\ \hline \end{tabular} Within each exposure interval and insecticide, means followed by the same letter do not differ significantly according to Kruskal-Wallis _H_-Test at \(p<0.05\). Where no letters exist, no significant differences were noted.  
\end{table} 
Table 3: _Cont._were found by [PERSON] [32], who found that chlorfenapyr was more effective for the control of _Tribolium_ spp. when applied to concrete than onto wood and ceramic surfaces. Another factor that is crucial during the post-exposure period is the presence or absence of food. The presence of food is positively correlated with survival, as mentioned by [PERSON] [17,25] and [PERSON] et al. [33]. In our study, petri dishes were without food, and the most logical explanation of the mortality of some insect species on surfaces may be attributed to the lack of food [19]. This study notably investigated the delayed effect, as in \"real world\" scenarios, where certain areas may be treated, partially treated, or untreated. This implies that insects may encounter a treated surface and subsequently be transferred to an uncontaminated surface. In our study, the species had a delayed mortality rate of 100%, indicating that exposure to treated surfaces can be lethal over extended observation periods and that the insect species do not exhibit recovery. It also implies that the active substances utilized have long-term hazardous effects, and the insects are unable to recover from the first exposure. As a result, this study supports the ability of surface treatments to provide long-term control even when insects are not constantly in contact with the treated areas. This study highlights the significant effects of surface type, exposure time, and insect species on the efficacy of three commercial insecticides applied as surface treatments. Alpha-cypermethrin and spinosad exhibited rapid and consistent insecticidal activity, while pirimiphos-methyl required a longer duration to achieve full mortality (7 days). Surface type played a crucial role, with non-porous materials (metal and ceramic) enhancing insecticide effectiveness compared to porous surfaces like concrete. Among the tested formulations, the pyrethroid was greater across multiple surfaces and multiple time points in both species.