Studies On The Biological Activity And Action Mode Of Vitex Negundo Volatile Oil To Main Stored-product Insect Pests

Vitex negundo L. belongs to Vitex Linn..Verbenaceae. It distributes widely in China, and is abundant in the natural resources of Mount Tai.Tested with Sitophilus zeamais, Rhizopertha dominica, Callosobruchus chinensis, Oryzaephilus surinamensis, and Tribolium castaneum that are main stored-product insects. The method of extracting insecticidal active material from Vitex negundo, and the action mode of the extracting material to the pests were studied systematically in this paper. The action mechanism of the extracting material to the pests was researched tentatively also. The study provides the basis for the development and utilization of this insecticidal plant in the future, and it has theoretical and practical meaning for the IPM. The main results are as follows:1. The steam distillation, cold-dip and supercritical CO₂ method was used to extract the active material in the seeds and leaves of V. negundo. We find the Insecticidal activity of V. negundo leaves extracted with steam distill is the best.2. Biological activity of V. negundo volatile oil to S. zeamais, R. dominica and C. chinensis indicate that V. negundo volatile oil has distinctly Insecticidal activity, and it can control F₁ population effectively. V. negundo volatile oil which mixed with wheat at a dosage of 0.4% by weight exhibited inhibiting effect to Sitophilus zeamais, R. dominica and C. chinensis, at the same dosage, the inhibiting rate is above 85% to O. surinamensis and T. castaneum.3. Contact application is main action mode of V. negundo volatile oil. S. zeamais, R. dominica, C. chinensis, 0. surinamensis, and T. castaneum treated by paper strip method. The LC₅₀ of S zeamais and R. dominica in 72h were respectively 0.3377mg·cm^-2 and 0.3213mg·cm^-2, the result indicated that the V. negundo volatile oil exhibited high contact toxicity. And the volatile oil exhibited distinct deterring effects to C. chinensis, O. surinamensis, and T. castaneum, V. negundo volatile oil which mixed with wheat at a dosage of 0.4% by weight exhibited deterring effects in 72h, the rate deterring effects is...