Abstract

Latoia viridissima (Lepidoptera: Limacodidae) is one of the main pests affecting oil palms (Elaeis guineensis) in Côte d'Ivoire. Controlling this pest requires prior knowledge of its development cycle. Therefore, this study was conducted from May 2023 to December 2024 at the CNRA station in La Mé, with the aim of updating the biological data on this pest and evaluating the effectiveness of a chemical insecticide. The results showed that females lay an average of 91.43 eggs, with a fertility rate of approximately 61.79%. This insect goes through eight larval stages and has a lifespan of approximately 66 days, with survival rates ranging from 54% to 92%. The development cycle lasts 107.91 days on average, with a sex ratio of 0.80 in favour of females. These data provide an essential basis for planning control strategies. In this series, efficacy tests were conducted on two groups of larvae (stages 1–3 and 4–8). Four concentrations were evaluated: one for the reference insecticide cypermethrin (0.13 g/L) and three for the lambda-cyhalothrin and acetamiprid formulation (0.0047, 0.014 and 0.023 g/L). Young larvae (stages 1 to 3) proved to be more sensitive to the treatments: 100% mortality was achieved with the lambda-cyhalothrin + acetamiprid formulation (0.023 g/L) within 48 h, and within 24 h with cypermethrin (0.13 g/L). In the more advanced stages (stages 4 to 8), mortality rates reached 95.40% for the lambda-cyhalothrin and acetamiprid formulation (0.023 g/L) and 100% for cypermethrin (0.13 g/L) after 72 and 48 h, respectively. In conclusion, these biological and toxicological data show that the lambda-cyhalothrin and acetamiprid formulation could be used reasonably in a control programme. However, field trials are necessary to confirm its efficacy.