Plants can not escape the attacks of pests, like a caterpillar, aphis, rodents, fungi, or weeds (plants disruptors). The presence of pests of plants will lower crop yields. To prevent and eradicate the pest plant is needed chemicals called pesticides.There are several types of pesticide use are adjusted to the type of pest attack. One type of pesticide is usually used for one type of pest.a. InsecticideUsed to prevent and eradicate the insect pests, such as aphis, grasshoppers, and caterpillars. Insecticides can also be used to exterminate insects in farm or household. Insecticides are often used, namely propoksur, diazinon, arsenic (III) oxide, and lead acetate.b. RodenticidesThis type of pesticide used to prevent and eradicate the insects rodents (mice) in agricultural land, households, or warehouse. Examples of rodenticides, among other arsenic compounds (arsenic), thallium sulfate, and sulfur.Sulfur is typically used by burning. The smoke arising from burning it and then directed into a rat hole.c. HerbicideUsed to prevent and eradicate the nuisance plant attack (weeds), such as reeds and grasses. Examples of herbicides such as ammonium sulfonate and pentachlorophenol.d. FungicideThis type of pesticide used to prevent and eradicate the fungus attacks. For example, sodium dichromate and organomerkuri.