The invention discloses a
plant extract for killing pests and a preparation process of the
plant extract, and relates to the technical field of biopesticides, and the technical key points are as follows: the
plant extract is selected from one or more of adhatoda vasica Nees, azadirachta indica, nigra sativa, parthenium hysterium and oriental arborvitae
Thuja orientia, and the extract contains
phytosterol,
saponin,
diterpene, flavone and
alkaloid. Contact and residual
toxicity tests are carried out on the cigarette beetles cultured in a laboratory, the experimental result shows that the neem and adhatoda vasica extracts have remarkable
toxicity and repelling effects on the cigarette beetles, the neem has the highest
toxicity, and the LC50 value is the lowest. The method comprises the steps of
plant collection,
drying,
grinding,
solvent extraction, rotary
evaporation and the like so as to obtain high-concentration active ingredients. The plant extract of the invention can be incorporated into the manufacture of novel biological insecticides to reduce the harm of cigarette beetles.