Phytochemical-mediated variation in growth, feeding, and life table parameters of Phthorimaea operculella (Lepidoptera: Gelechiidae)

The potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is a major constraint on commercial potato production worldwide. Larvae damage plants by mining the foliage and penetrating tubers, thereby rendering them unmarketable. In the present study, the effects of six potato cultivars (Agria, Fontane, Javid, Jelly, Marfona, and Sprit) on the life table parameters and feeding efficiency of P. operculella were evaluated under controlled laboratory conditions. Data were analyzed based on the age-stage, two-sex life table method. In parallel, we examined biochemical traits associated with host susceptibility and quantified protein, starch, flavonoid, and phenolic contents to evaluate their relationships with the ecological performance and nutritional indices of the pest. The results indicated that P. operculella exhibited the shortest developmental period when reared on Fontane, Marfona, and Sprit, whereas the longest development time was observed on Agria. The Javid cultivar supported the highest intrinsic rate (r) and finite rate of increase (λ), while Agria and Marfona resulted in the lowest values for these parameters. The highest relative growth rate (RGR) was recorded on Fontane, Javid, and Sprit, whereas Agria yielded the lowest RGR. Correlation analyses revealed a positive association between tuber starch content and both developmental duration and net reproductive rate (R₀). In contrast, phenolic content was negatively correlated with R₀ and r. Cluster analysis classified Javid as a relatively susceptible cultivar, while Fontane, Sprit, and Marfona were identified as comparatively more unsuitable to P. operculella population growth. Overall, these findings provide valuable insights into host plant-pest interactions and can contribute to the development and refinement of integrated pest management (IPM) strategies against the potato tuber moth.