Toxicity and Repellency of Chenopodium Oil To Four Species of Stored-Product Insects²

Chenopodium oil, an essential oil of Chenopodium ambrosioides L., was evaluated for its toxicity and repellency to adults of Callosobruchus machulatus (F.), Sitophilus oryzae (L.), Lasioderma serricorne (F.), and Tribolium confusum Jacquelin du Val. Topically applied, the oil was highly toxic to C. maculatus (100% mortality at 40 μg/insect) and L. serricorne (92.5% mortality at 50 μg/insect), moderately toxic to S. oryzae (52.5% mortality at 50 μg/insect), and only slightly toxic to T. confusum at 50 μg/insect. When applied to the surface of wheat, the oil was highly repellent to S. oryzae. When applied to wheat or black-eyed peas, the oil reduced infestations of S. oryzae and C. maculatus at dosages of 2000 and 1000 ppm, respectively.