Insecticidal Potential of Spice Extracts of Syzygium aromaticum, Trigonella foenum-graecum and Ferula assa-foetida against Grain Weevil Sitophilus oryzae (L)

The preservation of post-harvest storage products, such as grains and rice, is often plagued by insect pests, with the rice weevil (Sitophilus oryzae L.) standing out as important. This study evaluates the efficacy of spice extracts of Syzygium aromaticum, Trigonella foenum-graecum and Ferula assa-foetida against S. oryzae at varying concentrations. Extracts exhibited toxicity that inhibited egg development and larval progression, with deformations observed at lower concentrations leading to larval death at higher concentrations. Qualitative and quantitative assessment of insect α-amylase activity revealed significant decreased activity with prolonged exposure. The study demonstrated increasing mortality rates with the combined spice extracts displaying the highest efficacy followed by S. aromaticum, T. foenum-graecum, and F. assa-foetida extracts, indicating promising insecticidal activity against S. oryzae.