Effect of Seed Oils of Trigonella foenum-graecum and Peganum harmala on the Life Cycle of Trogoderma granarium
Department of Biology, Colleg of Education, University of samarra, Iraq.
Research Article
International Journal of Biological and Pharmaceutical Sciences Archive, 2026, 12(01), 029–035.
Article DOI: 10.53771/ijbpsa.2026.12.1.0066
Publication history:
Received on 12 April 2026; revised on 03 July 2026; accepted on 06 July 2026
Abstract:
The khapra beetle, Trogoderma granarium (Everts), is among the most economically important insect pests of stored grains and grain products around the world, resulting in extensive quantitative and qualitative losses in the process of storage. This study was carried out to evaluate the insecticidal effect of seed oils of Trigonella foenum-graecum (fenugreek) and Peganum harmala (harmal) on T. granarium at the fourth instar larval and adult stages. The three concentrations of each oil used (2%, 4%, and 8%) were investigated. Mortality of larvae was measured after 24 hours and 48 hours of exposure, while mortality of adults was measured after 24 hours, 48 hours, and 72 hours. It was found that the mortality increased considerably with an increase in the concentration and exposure period of the oil. The maximum larval mortality occurred at 8% concentration after 48 hours, which reached 96.6% and 71.6% for T. foenum-graecum and P. harmala oils, respectively. However, maximum mortality of the adult insects also occurred at 8% concentration after 72 hours, which reached 94.6% and 89.6% for T. foenum-graecum and P. harmala oils, respectively. The results demonstrate that both plant oils have insecticidal potential against T. granarium, with the oil from fenugreek seeds showing more activity compared to the oil from harmal seeds. The oils from these plants can be used as green substitutes to chemical insecticides for managing stored grain pests.
Keywords:
Trogoderma granarium; Trigonella foenum-graecum; Peganum harmala; Plant oils; Stored grain pests; Mortality
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