Oviposition Preference and Larval Performance of Spodoptera exigua on Different Cultivars of Sugar Beet

Abstract

The beet armyworm, Spodoptera exigua, is a highly polyphagous lepidopteran pest causing severe defoliation in sugar beet and other economically important crops. The present study investigates oviposition preference and larval performance of S. exigua on different sugar beet cultivars to assess host plant suitability and resistance expression. Adult moths were exposed to multiple cultivars under controlled conditions to evaluate egg-laying preference, while larval development, survival, pupal weight, and adult emergence were recorded on each cultivar. Results revealed significant variation in oviposition behavior among sugar beet cultivars, indicating differential host selection by gravid females. Certain cultivars were highly preferred for egg deposition, while others were less attractive, suggesting the presence of deterrent plant traits. Larval performance varied considerably across cultivars, with some supporting faster development, higher survival rates, and increased pupal weight, indicating higher host suitability. In contrast, resistant cultivars negatively affected larval growth, prolonged developmental duration, and reduced survival and adult emergence. The study demonstrated a positive correlation between oviposition preference and larval performance in susceptible cultivars, whereas resistant cultivars disrupted this relationship. Plant morphological and biochemical traits, including leaf surface characteristics and secondary metabolites, are likely responsible for observed differences in host acceptance and suitability. These findings highlight the importance of host plant resistance in managing S. exigua populations in sugar beet agroecosystems. Overall, the study provides valuable insights into insect–plant interactions and supports the use of resistant cultivars as a sustainable strategy for reducing pest damage and improving integrated pest management in sugar beet cultivation systems.