## 4 Discussion  
### Olfactometric Bioassays  
Previous studies have demonstrated that olfactory signals from damaged and fermented fruits play a crucial role in food source recognition by SWD [52; 53]. These flies are \begin{table}
\begin{tabular}{c c c} \hline \hline
**Variety** & **WVM Bait (fly/ha)** & **Control (fly/ha)** \\ \hline Regina & 16,104 * & 1944 \\ Lapins & 22,491 * & 8330 \\ Stella & 13,050 * & 3887 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Number of flies captured per hectare (flies/ha) in traps with WVM bait and in the control for three fruit tree varieties (Regina, Lapins, and Stella). The asterisk (*) indicates significant differences (\(p<0.05\)) between the bait treatment and the control within each variety. Figure 6: Total number of individual _Drosophila Suzuki_ captured with the WVM bait in delta-type traps placed in different cherry varieties (Stella, Regina, and Lapins) at the Maquehue Experimental Field, La Araucania region. * Indicates a significant difference between treatment and control according to Student’s t-test (\(p\leq 0.05\)) (**A**). Sex ratio of females and males captured with the WVM bait during the duration of the trial. * Indicates a significant difference between females and males captured, according to the Poisson distribution (\(p\leq 0.05\)) (**B**). typically attracted to fermented sweet substrates, such as decaying fruits. However, their attraction has also been reported to increase in response to the aromas of wines, vinegas, and fermentation volatiles, including acetic acid and ethanol [23; 54; 55]. For instance, studies employing gas chromatography coupled with electroantenographic detection (GC-EAD), along with laboratory bioassays and field capture experiments, were conducted to identify the volatile compounds from wine and vinegar involved in the attraction of SWD [22; 52]. In addition to acetic acid and ethanol, consistent GC-EAD responses were observed for 13 volatile compounds from wine and 7 from vinegar, with all active GC-EAD compounds from vinegar also present in wine. In a field capture experiment, both the 9-component vinegar blend and the 15-component wine blend were equally attractive when compared to a blend of acetic acid and ethanol, but they were less attractive than the combined wine and vinegar blend [52]. The above is consistent with the results obtained in the olfactometric assays presented in this study, where flies exhibited a significant preference for the WVM stimulus (Figure 1), a blend of wine and vinegar. Furthermore, this attraction response is consistent with findings reported by [PERSON] et al. [56], who studied the same dipteran species using olfactometric techniques and volatiles from _Osyris wightiana_, a wild host plant classified as a secondary host of SWD. The authors reported a significant attraction of SWD to the fruits and volatile extracts of _O. wightiana_ compared to the control (65-85%), which aligns with the attraction range observed in this study (70%). In all cases, as in our study, SWD were strongly attracted to the stimuli, likely due to the characteristic fermentation aromas [57]. Interestingly, SWD exhibited a \"repellent\" behavior to SAG I and SAG II baits under laboratory conditions, contrary to what happens under field conditions. A possible explanation for this behavior could be due to the volume used in the olfactometric tests (10 \(\mu\)L) compared to the traps used for monitoring, which contain over 250 mL of bait [48]. Research with mosquitoes (Diptera) refers to the care that must be taken when replicating the concentration of compounds in olfactometric tests to which the insect is accustomed in nature [58]. In addition, SWD's olfactory receptors may not adapt to these baits in such low volumes or concentrations. On the contrary, SWD may be able to adapt its olfactory receptors to the WVM bait because this bait is also composed of wine, which has a high content of volatile organic compounds, increasing the possibility of receiving them.