Canola oil is a good organic pesticide that can be used to control most soft bodied insects. Mix a cup of canola oil with 3-4 litres (a gallon) of water and a few drops of a safe detergent (so they mix properly). Spray it over pest insects but be aware that it will also harm soft bodied beneficial insects so be sure you're only spraying pests. If you're spraying edible plants, make sure you use cooking canola oil. If you want to make your own canola oil, make sure you're growing the edible canola varieties, some non-edible varieties contain high levels of a toxic acid, making them harmful to human and pet health.
Do not make a more concentrated mix than this otherwise your plants may be harmed.