When would an organic grower need to use a pesticide or pest control product?

In a natural ecosystem, predators keep plant pests in check, while diseases strike individual plants or may even wipe out a species. Nature constantly works to correct imbalances. Organic farmers also strive for such a balance, but farming interferes with the native mix of plants and animals, and so farmers must contend with the problems that arise. They must also meet customer expectations of quality - and do all of this in an economic fashion. The allowed pesticides are, therefore, sometimes used as a corrective measure when cultural methods of pest control have failed. Organic farmers look for pesticides that target their pest specifically while impacting the ecosystem as little as possible. For example, if a field of tomatoes has attracted a large population of tomato hornworms, a natural toxin can be sprayed which harms only leaf-eating caterpillars. If aphids are the problem, a light petroleum oil spray could be used to suffocate these soft-bodied insects without harming their ...  more