There are different kinds of insecticides that can be used for bonsai, depending on the type of pests you want to control and the level of toxicity you are comfortable with. Some of the common pests that affect bonsai are spider mites, aphids, mealybugs, and scale insects. Some insecticides are systemic, meaning they are absorbed by the plant and kill any insects that feed on it. These can be effective against root pests, but they may also harm beneficial insects or contaminate nearby plants. Some examples of systemic insecticides are imidacloprid, acephate, and dinotefuran. Other insecticides are contact, meaning they only kill the insects they touch. These are safer for the environment, but they may require more frequent applications. Some examples of contact insecticides are insecticidal soap, neem oil, and garlic spray.