HCud

1. Pest-an unwanted organism Pesticide- chemical poison that is used to kill an unwanted organism.

2. If used correctly, pesticides can benefit an ecosystem. A field of corn can tolerate a few corn borers without suffering, and a few medflies wouldn't destroy all the apples in an orchard. Pests become problems when their populations grow. By using the right amounts of pesticides, these pests are easily rid of in these ecosystems. Farmers are aable to produce larger quantities of food and have helped reduce the indcidence of insectborne diseases such as malaria, yellow fever, and typhus by reducing the populations of the disease-carrying insects. Pesticides are convenient weapons for farmers, homeowners, and public health workers all over the world.

However, while there are major benefits for using pesticides, there are some major disadvantages. When a pesticide is sprayed on a crop, it is estimated that only ten percent of the chemical spray actually comes into contact with the isect pests that are being targeted. The other 90 percent is taken up by other organisms as well as soil and water. Pesticides destory pest organisms and their natural predators. If all predators are killed and a few pests are still living, the pests are able to reproduce and there aren't any predators to rid of the pests. The pest problem would be worse than it was the first time around. Some past pesticides, like DDT, have some serious side effects that weren't immediately spotted. The side effects may be severly dangerous and would have to be removed or banned. Also, some organisms had a mutation that made them resisitant to some pesticides. When they reproduced, they passed that gene down and a new population of a pest would all be immune to a certain pesticide.

3. Even though pesticides work most of the time, there is a risk involved when using them. There are alternatives to using pesticides to control pests. Natural predators are able to be used to control a pests population. A pest's biochemical characteristics are also used to control its population. Other methods called cultural controls are used to discourage pest growth, or breeeding plants that are resistant to pests. Not all alternatives are foolproof just like not all pesticides will work.

By preserving natural predators of some pests, the pest's population is kept under control by the predators. An insect called the cottony cushion scale had become a severe pest in teh citrus groves of California. A beetle was a predator of the scale insects and was introduced to control the pest. Another method is sterilizing males of a pest species and introducing them into the infested area. When the males are released, they mate with females, but no offspring are produced. Integrated pest management is a system that usees biological, autocidal, and cultural controls along with chemical pesticides to mangage thte size of pest populations. This is also used to control a pest's population.