The most common methods of pest control are biological control, chemical control and integrated pest management.
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Biological control: this is a natural way of controlling pests. This is done by introducing a species, which is a natural predator of the pest in question. However, using this form of pest control can oppose problems. It must be researched in great detail by qualified scientists before a predator is introduced this is because it might not work out as planned. “All biological control requires careful analysis of the ecosystem into which it is being introduced.” (Quote: Quote from Taylor, Green and Stout: biological sciences 1 & 2 page 337) This form of control was attempted in Australia when the Cane toad was introduced from Hawaii to control the Cane grubs, which were destroying Cane crops. However, the Cane toads did not eat the grubs and could not be removed because they had multiplied so they gradually out competed all of the native species and because there was no natural predators for the toad the population kept growing. This issue is very serious as it altered the natural habitat in Australia as far as wildlife is concerned because of a foreign species being used to control a native species when all of the consequences were not thought about (class notes) “Cane toad was introduced as a means of biological control the cane toad is now a predator of native species.” (Quote: Toole and Toole: understanding biology page 381)
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Chemical control: this is generally effective, cheap, and safe if handled correctly. However, they can have adverse effects on nature. Chlorinated hydrocarbon insecticides such as , for example is toxic to insects, fish, and other wildlife; the insecticides may be found in meat and milk, or they may lie in the soil for many years and cause problems. Another problem is that some species of insects build up resistance to chlorinated hydrocarbon, organic phosphate, and carbamate insecticides. These disadvantages can be overcome only by persistent search for new and safer insecticides.
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Integrated pest control: Farmers depend on a method called "crop rotation" to control pests. A variety of crops are planted and then rotated to different fields each year. Pests that attack one variety will die off when that variety is replaced by a different crop the following year. In many cases, removing their preferred food and shelter can control pest populations. Covering food that attracts flies, or removing garbage that attracts animal pests, is often all that is required.
Integrated Pest Managementtreats a crop as an ecosystem, and uses different methods to control the pests within it. The guiding principle of integrated pest management is that active pest control is only undertaken when pest populations are at, or near, "economic thresholds" which may threaten a crop's commercial value.
Integrated pest management uses biological controls wherever possible, but it also uses other techniques if necessary including limited, specific applications of a chemical pesticide. The integrated approach actually tolerates some pests, so long as the damage they cause remains minor. In fact, small pest populations are welcome, since they ensure that the pest's natural enemies will also survive in the system.
Integrated pest management is not always easy, or even possible. “Climatic conditions, an absence of natural enemies, or the biological complexities of the crop itself may prevent a focused attack on one pest only.” (Quote: NASE Database: documents by topic: chemicals/pesticides )This technique would require a lot of time, knowledge and dedication.
Natural pesticidal products, also called botanical pesticides, are available as alternatives to synthetic chemical formulations. Although thought of by some as "natural," and therefore assumed to be harmless, safety clothing must be worn when spraying these, even though their toxicity is low to warm-blooded animals. Some botanical pesticides are toxic to fish and other cold-blooded creatures and should be treated with care.
The botanical insecticides break down readily in soil and are not stored in plant or animal tissue. Often their effects are not as long lasting as those of synthetic pesticides. For example, Pyrethrum works against Pickleworms, aphids, leafhoppers, spider mites, harlequin bugs, cabbageworms, Mexican bean beetles, flea beetles, flies, and squash bugs.
Advantages of using biopesticides include: Biopesticides are usually inherently less harmful than conventional pesticides. They generally affect only the target pest and closely related organisms, in contrast to broad spectrum, conventional pesticides that may affect organisms as different as birds, insects, and mammals. Biopesticides often are effective in very small quantities and often decompose quickly, thereby resulting in lower exposures and largely avoiding the pollution problems caused by conventional pesticides. “When used as a component of Integrated Pest Management (IPM) programs, biopesticides can greatly decrease the use of conventional pesticides, while crop yields remain high.” (Quote: Britannica encyclopaedia CD-ROM: search: what is integrated control?)
Conclusion
From what I have looked at and discussed during this essay you can see that pesticides have an intended good purpose however, they have some seriously bad effects and should be permanently banned from being used then there would be less debate over whether or not certain fruits from certain places are safe to ear.
Bibliography
- Taylor, Green and Stout: biological sciences 1 & 2 page 334
- Table information from: Campton’s interactive encyclopaedia 1999(CD-ROM)-pesticides
- Toole and Toole: understanding biology, table 18.4 page 376
- Toole and Toole: understanding biology page 377
- Taylor, Green and Stout: biological sciences 1 & 2 page 337
- Toole and Toole: understanding biology page 381
- class notes
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NASE Database: documents by topic: chemicals/pesticides
- Britannica encyclopaedia CD-ROM: search: what is integrated control?
