Sugar-Induced Modulation of Potato Tuber Moth Infestation: Field Evidence from Algeria

This study investigated the impact of foliar applications of sucrose, fructose and their combination (Suc + Fruc) on the infestation dynamics of Phthorimaea operculella in potato crops grown in Algerian fields. The experiment assessed the impact on the infestation rate, the number of mines, and the number of immature stages at the basal, median, and apical positions of the leaves. The treatments included sucrose (100 ppm), fructose (100 ppm), and Suc + Fruc (100 ppm). During the experimental treatments, the sucrose treatment resulted in the highest infestation rate (62.50 ± 13.64%), confirming its potent phagostimulatory effect. In contrast, the Suc + Fruc mixture led to the lowest infestation rate (32.29 ± 11.07%), which was significantly lower than the control rate. No significant differences in infestation were found between basal and apical leaves, but median leaves were significantly affected (p < 0.05), with sucrose increasing infestation. Mine numbers differed significantly at the basal stage (p < 0.05), with damage being reduced by the fructose and sucrose + fructose treatments. The abundance of immature P. operculella larvae varied significantly across treatments and leaf stages (p < 0.001), with the Suc + Fruc and fructose treatments reducing larval densities particularly effectively at the apical stage. The sucrose + fructose treatment was more effective at suppressing larvae than sucrose alone (p = 0.006). Abbott’s efficacy analysis revealed that the Suc + Fruc treatment was the most effective (31.12-36.67%). These results imply that balancing sucrose with fructose is a promising, eco-friendly way to manage P. operculella in semi-arid environments, offering an alternative to traditional pest control methods.