The invention discloses a composite natural insecticide for preventing and controlling red spiders and a preparation method of the composite natural insecticide. The composite natural insecticide comprises the following components in parts by weight: 50 to 80 parts of tomatoes, 30 to 50 parts of garlic, 20 to 40 parts of green Chinese onion, 20 to 40 parts of onion, 5 to 10 parts of ginger, 5 to 10 parts of Chinese prickly ash and 1 to 3 parts of
soap. The preparation method comprises the following steps of (1) weighing the Chinese prickly ash in proportion, adding water, heating to be in a slightly boil state, keeping the slightly boil state for 3 to 4 hours, standing, cooling and filtering, so as to obtain a filter liquor I for standby application; (2) weighing the tomatoes, the garlic, the green Chinese onion, the onion and the ginger in proportion,
mashing, adding the filter liquor I prepared in the step (1), soaking for more than 24 hours, filtering, adding the
soap and stirring to completely dissolve, so as to obtain a raw liquor of the composite natural insecticide. Raw materials of the composite natural insecticide are natural and environmental, and after being applied, the composite natural insecticide is harmless to human bodies and environments; the composite natural insecticide has a relatively strong tagging effect on the red spiders and has the advantages of good effect and no resistance; the preparation method has the advantages of simplicity and easiness in
raw material obtaining and is suitable for industrial production.