The Efficacy of Tobacco Leaf Powder Under Storage Conditions Against the Cowpea Beetle Callosobruchus maculatus

Abstract

The cowpea weevil, Callosobruchus maculatus (F.), causes significant losses by affecting the quantity and quality of stored cowpea seeds. Therefore, this study aimed to evaluate the efficacy of tobacco leaf powder (Nicotiana tabacum) in protecting cowpea seeds against C. maculatus under ambient storage conditions. The storage experiment was conducted in a non‑conditioned storage chamber from July 2024 to March 2025 (8 months). The temperature ranged from 10 to 36°C, and relative humidity ranged from 55 to 80%, reflecting local storage conditions. The results obtained showed that treatment with tobacco leaf powder significantly reduced the mean number of penetrated eggs from 81.01 to 11.19% two months after treatment, and reached 100% at eight months after treatment compared to the control. The treatment also reduced the net reproductive rate (R₀) of the pest from 76.14 to 2.19 % and shortened the mean generation time (T) from 54.00 to 44.45 days. These findings confirmed that tobacco leaf powder could be an effective and safe alternative to chemical treatment.

Keywords:

Insecticides, cowpea seeds, botanical powders, control, storage insects.