# Eco-Friendly Management of Acanthoscelides obtectus Through Individual and Combined Applications of 1,8-Cineole and Diatomaceous Earth

## TL;DR

Researchers tested eco-friendly methods to control Acanthoscelides obtectus, a bean pest, using diatomaceous earth and 1,8-cineole, finding that their combination is highly effective.

## Contribution

The study introduces a novel combination of reduced doses of diatomaceous earth and 1,8-cineole for effective pest control with minimal environmental impact.

## Key findings

- Combined application of 200 ppm DE and 2.5 ppm 1,8-cineole achieved 73.33% mortality in A. obtectus.
- No F1 progeny was observed with DE or combined treatments, indicating effective suppression of reproduction.
- Lower doses of DE and 1,8-cineole showed higher efficacy compared to higher doses of 1,8-cineole alone.

## Abstract

Stored-product insect pests are responsible for a substantial proportion of losses in stored agricultural commodities. Increasing awareness of the adverse effects of synthetic pesticides on environmental and human health has prompted researchers to seek alternative control strategies, with particular focus on diatomaceous earth and plant-derived essential oils. In this study, the control efficacy of diatomaceous earth (DE), 1,8-cineole, and their combination was evaluated against Acanthoscelides obtectus, an important storage pest that causes significant damage to stored beans. Although the insecticidal properties of 1,8-cineole have been documented, its high volatility and toxicity at elevated doses restrict its practical use. To minimize these disadvantages while enhancing its efficacy, the present study explored the use of reduced doses of DE and 1,8-cineole, both individually and in combination, as a control approach for this pest. The findings demonstrate that both DE and 1,8-cineole are effective against A. obtectus, and that their combined application results in high mortality rates along with suppression of F1 progeny. Overall, the results highlight the potential for developing specialized biological formulations or application strategies that capitalize on these observed interactions to improve the protection of stored products.

With growing concerns about chemical insecticides, there is also growing interest in safer, natural alternatives. This study investigated the individual and combined effects of two promising eco-friendly alternatives, diatomaceous earth (DE) and 1,8-cineole, a plant-based essential oil component, on adults of Acanthoscelides obtectus under laboratory conditions. Against the maximum doses of both products (DE 800 ppm, 1,8-cineole 5 ppm), A. obtectus showed 100% mortality within the first 24 h. Although mortality at lower doses (DE 25, 50, 100 ppm, 1,8-cineole 0.600, 1.2 ppm) began from the first day, it was not as effective. In the combined application of 200 ppm DE and 2.5 ppm 1,8-cineole, the mortality rate was 73.33 ± 8.81%, representing the most effective outcome achieved with the application of relatively low doses of DE and 1,8-cineole. No F1 progeny was observed at any dose of DE or in the combined applications. In contrast, F1 progeny occurred only at three doses of 1,8-cineole (0.150, 0.300, and 0.600 ppm); however, the number of eggs and emerging adults was markedly lower than in the control group and showed a statistically significant difference. Overall, the results obtained from DE alone and DE + 1,8-cineole applications were more effective.