In conventional agriculture, the control of plant diseases and insect pests relies mainly on the use of large quantities of chemical pesticides, which is the main cause of residual pollution of hazardous substances. With the development of the internationalization of agricultural trade and the improvement of people’s understanding of food safety, pollution-free food production has risen rapidly. The first problem to be solved in the production of pollution-free food is the residual pollution of chemical pesticides, that is, the prohibition and restriction of the use of chemical pesticides. The use of existing plant-based pesticide resources to prepare insecticidal fungicides, the prevention and control of vegetable pests and the production of pollution-free vegetables, no residue, no pollution, no adverse effects. There are many types of plant pesticides, and several simple, readily available plant pesticides are briefly introduced. (1) Peppers and peppers are widely grown in various parts of China. Mature fruits have insecticidal effects, but the content of insecticidal substances in seed coats and seeds is the highest. Mode of action: stomach poisoning, anthelmintic, antifeedant, fumigation. Targets for prevention and control: various vegetable aphids, whitefly and cabbage caterpillars. How to use: Add chili powder to powder, add 50 times of water to stir, place it overnight, filter it with cloth, and spray it on the crop. Or ground the pepper to a fine powder, add water, add soap tablets or liquid soap, stir well and sprinkle on the crop. (2) Garlic Garlic is widely cultivated in fields, gardens and courtyards. All parts of the plant contain bactericidal active ingredient allicin. Mode of action: kill bacteria, fungi and nematodes. Control subjects: Vegetable root-knot nematodes, gray mold, bean rust, cucumber keratoses, melon anthracnose, and potato storage diseases. Usage: 1kg of garlic peeled and smashed, add 2kg of water, soak it for 0.5 hours and filter it to residue. Use water to dilute 20 times spray. When the garlic is processed, there is a peeling process. When peeling, cut the garlic pedicle first, immerse in the cylinder for 24 hours, and then remove the skin. The garlic in the water contains a lot of allicin, this water can be clarified and miscellaneous, and directly sprayed to prevent and treat various diseases, and used for waste. (c) Tobacco Tobacco contains nicotine, which has an insecticidal effect and does not cause any damage to humans, animals or the environment. In ancient China, there were records of the use of tobacco leachate to control plant pests. The roots, leaves and stems of tobacco contain large amounts of nicotine. Cigarette smoke, tobacco stems, moldy tobacco leaves, tobacco leaves produced during the production process of cigarette factories, tobacco tops, soot, old diseased leaves laid down by tobacco farmers, residual stalks and roots at the time of harvest, etc. can all be used to prepare crude extracts. preparation. Mode of action: contact, stomach poisoning, withdrawal, and fumigation. Targets for prevention and control: various vegetable aphids, cabbage caterpillars, leaf miners, crickets, leeks, and onion thrips. Method of preparation and use: Soak 1kg chopped tobacco leaves and stalks in 15L of water for 24 hours, add a small amount of soap as emulsifier, remove the tobacco residue after 24 hours, and spray with a small spray sprayer. (d) Ricinus communis plants contain ricinine in various organs. Ricinine has the pharmacological effect of parasitizing insects. In the north of China, a large amount of castor is often planted in the farmland and in front of houses. Ramie leaves: ramie leaves with water (leaf water ratio: fresh leaves 1:8, dry leaves 1:50), cook for 1 hour, filtered to the residue, add a small amount of soap, can be sprayed to kill pine caterpillars. Castor seed: Stir the ramie seed with water (the ratio of seed water is 1:1) and mix evenly, then pour in a small amount of soapy water, and dilute it with water to 100-150 times the liquid, which can spray and kill various kinds of vegetable aphids. Ricinus communis: cakes with water and soap (the ratio is 1:5:0.1). After dipping, the soap must be opened and filtered to remove slag, which can be used to kill gold turtles and various vegetables. Ramie straw: The leaves, stalks and roots of ramie are dried and crushed, and applied to the soil at a dose of 50 kg per acre, which can prevent the damage of earthworms. (5) Most of the plants in Tartarianaceae contain insecticides, insecticides, and refusals of food quality, such as Indian oysters, Chuanxiong, and bitter buckwheat. Tartary buckwheat is a deciduous tree of the family Polygonaceae. It is widely distributed in northern China. Its roots, leaves and fruits contain buckplein, which can prevent and treat various aphids, planthoppers, cabbage caterpillars and aphids. Bark and branches and leaves contain buckwheat, alkaloids, kaempferol, phenol and other substances, the fruit contains bitter taste; nucleosides contain bitter buckwheat oil. Mechanism of action: insecticidal, anthelmintic, antifeedant, growth inhibitory effects. Targets for prevention and control: Helicoverpa armigera, aphids, diamondback moth, beet armyworm, ground tiger, cabbage caterpillar, potato ladybug, cockroach, leafhopper, leafminer and various whitefly. Method of preparation and use: Preparation of eucalyptus seed water extract: Collect eucalyptus fruit falling on the ground, remove the flesh, and wash the flesh on the seed. Then the seeds are stored in a ventilated place. If necessary, the husks are shredded and shredded in a cloth and soaked in a bucket for 24 hours. The ratio is 25-50 g per liter of water. The immersion liquid thus made is very effective for Pieris rapae, Melon and Aphids. Put 5kg of eucalyptus seed powder in a cloth and soak it in a bucket for 12 hours. Then squeeze the bag firmly. Use a little water-soluble 10kg soap and pour into the bucket. Stir thoroughly and add water to make the liquid volume 100L. It can prevent corn borer. Production of eucalyptus oil: handmade eucalyptus oil. First peel the seeds, put them into the pot and chop them into a brown paste. Add a little water into the balls and knead them in the pot until the surface seeps out the vegetable oil. Then press it hard and the eucalyptus oil will drip. In this way, 1kg of eucalyptus kernels can be used to extract 100-150ml of eucalyptus oil. Eucalyptus oil emulsified with a small amount of soap and water, diluted with water to 100-200 times the liquid can effectively control fleas and mires. Plant-based pesticides prevent insects, protect the environment and protect the environment, and are the first choice for the production of pollution-free vegetables. There are also a large number of types of bactericidal and insecticidal agents in existing plants, such as skunk, mandala, purslane, and walnuts. For our further research and application. Source: "Agricultural Science and Technology Newsletter"