Toxic Efficacy of Nerium oleander Extracts as a Precise Strategy for Managing Pomacea canaliculata (Gastropoda) Eggs

The golden apple snail (Pomacea canaliculata) is a globally destructive invasive species. Existing control strategies primarily target adult snails, yet these approaches often fail due to the snails’ robust shells and lack of effective toxicity. To address this problem, extracts from Nerium oleander, Alocasia macrorrhiza, Euphorbia tirucalli and Aconitum carmichaelii were tested on the snail eggs. All four extracts exhibited toxicity at a 75% concentration, with N. oleander being the most potent. Specifically, this extract achieved a 95.42% mortality rate at 75% concentration and induced complete embryonic death at the 50% concentration. All four extracts induced significant oxidative stress-related physiological alterations in the eggs. Notably, N. oleander extract reduced the soluble protein content by 12% and altered key antioxidant enzyme activities (a 1.29-fold increase in SOD and CAT; a 48% decrease in ALT; a 3.52-fold and 5.67-fold increase in AST and POD, respectively). Field trials showed that fresh and dried N. oleander leaf extracts inhibited egg hatching by 96% and 93%, while embryonic observations confirmed developmental impairment. Further, to identify the bioactive components of N. oleander leaf extracts and lay a foundation for subsequent pesticide development, HPLC-MS analysis was performed, and 27 compounds belonging to 7 groups were identified. Collectively, N. oleander treatment induced oxidative stress-related physiological alterations and embryonic developmental impairment, which contributes to its ovicidal outcome. These findings lay a theoretical foundation for plant-derived ovicide development, inform eco-friendly pest management policies, and guide field control practices, highlighting N. oleander as a promising candidate for targeted P. canaliculata egg control.