# Efficacy of the Combination of λ-Cyhalothrin and Chlorantraniliprole Against Four Key Storage Pests

## TL;DR

This study tests a pesticide mix's effectiveness against four major grain pests, finding it highly effective against some species but less so against others.

## Contribution

The study introduces a novel insecticidal combination of λ-cyhalothrin and chlorantraniliprole for managing storage pests with variable efficacy across species and commodities.

## Key findings

- The combination effectively suppressed progeny production of Sitophilus oryzae and Rhyzopertha dominica for 30 days.
- Trogoderma granarium and Tribolium castaneum showed lower mortality and higher progeny production compared to other species.
- Wheat showed higher mortality rates and lower progeny production than rice and maize when treated with the insecticide combination.

## Abstract

The present study evaluated the effectiveness of the combination of λ-cyhalothrin and chlorantraniliprole against Trogoderma granarium, Tribolium castaneum, Rhyzopertha dominica, and Sitophilus oryzae, on treated wheat, rice, and maize. Sitophilus oryzae and R. dominica were the most susceptible species in both laboratory and persistence trials. The progeny production of S. oryzae and R. dominica was almost suppressed in laboratory trials on 5 ppm-treated wheat and persistence bioassays, 30 days post-storage. Trogoderma granarium and T. castaneum were less affected by the tested insecticidal combination, suffering lower mortality rates and producing higher progeny, compared to S. oryzae and R. dominica. Concerning the different commodities, treated wheat led to higher mortalities and lower progeny vs. rice and maize. These findings demonstrate that the combination of λ-cyhalothrin and chlorantraniliprole is effective under testing of different parameters, such as the type of the grain commodity or insect species.

With over 1000 species of pests causing losses in both the quantity and quality of stored food, insect contamination poses significant challenges. The present study assesses the efficacy of the combination of λ-cyhalothrin and chlorantraniliprole against four key storage pests—Trogoderma granarium, Sitophilus oryzae, Rhyzopertha dominica, and Tribolium castaneum. Laboratory bioassays demonstrated species-dependent mortality, with S. oryzae and R. dominica suffering 100% mortality in several tested scenarios. A 90-day persistence trial revealed decreased efficacy over time, especially for T. granarium (32.0–71.4% at 0 days and 0.0–7.5% at 90 days) and T. castaneum (38.8–82.7% at 0 days and 0.0–12.7% at 90 days) vs. S. oryzae and R. dominica. Progeny production of S. oryzae and R. dominica was almost suppressed in persistence trials (0.4 individuals per vial and 1 individual per vial, respectively) after 30 days of storage at the dose of 5 mg/kg wheat. The results highlight the variability in insecticidal performance based on species, dose, exposure, and commodity type, emphasizing the need for tailored pest management strategies in the storage environment.