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Is Biological Control Better than Chemical Control?

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Introduction

Is Biological Control Better than Chemical Control? It is important that plants have the right conditions to grow successfully and produce a good harvest in. These conditions include space, good sources of light and water, an appropriate temperature, and a supply of inorganic ions. With crop plants this is especially important since the greatest possible yield needs to be achieved. However, there are factors which affect the yield of a crop produced, such as competition, disease, and pests. Pests are unwanted organisms that reduce the quality and growth rate of a plant, also likely to affect the amount of seed it produces. Most pests only cause significant damage to the environment when their population reaches a specific level. This is called the 'economic injury level.' Controlling all of these factors, so that this level is not reached can be done so using either biological or chemical control. I shall be investigating into these two methods to distinguish which is the better out of the two. Biological control relies on the introduction of other living organisms or biological products to control pests. A predator or a parasite of the pest is usually used in this case. ...read more.

Middle

This can cause the leaves of the plant to curl over, reducing the surface area and therefore its ability to photosynthesise. Also, the plants quality is ruined and eventually it may die, so insecticide is used. An example of a process used to kill aphids is the use of light traps. They are placed around a country to collect samples of flying insects. It estimates when the population of aphids is increasing, so that farmers know when to spray their crops with insecticide. One advantage biological control has over pesticides is that it is specific; meaning it only affects the target pest in a harmful way. The predator is only going to kill the pest, nothing else. However, this is not the case with pesticides. They are the cause of many ecological problems. Not only do they kill the pest, but they also may harm other organisms including the predators of the pest. Pesticides also have dangerous affects on the atmosphere. Bromomethane is used to fumigate pests. This substance is one reason for depletion of the ozone. This can have repercussions such as increased cases of human skin cancer because more damaging ultraviolet radiation can pass through the atmosphere and reach Earth. ...read more.

Conclusion

However, biological control does have its weaknesses. The time taken to see any reduction in the number of pests can be very extensive due to the length of time the predator needs to establish itself in its new surroundings. Also, the pests are only suppressed, meaning the pest population is only reduced, never completely destroyed. Using a chemical pesticide on the other hand would exterminate the pest in most cases. Also the issue of genetic engineering of organisms is controversial. On the down-side the toxins produced by the process of gene transfer may have harmful effects on beneficial organisms or on human health, but on the up-side the transferred gene might 'escape' into related species of the organism. I think that neither biological nor chemical control used alone is ideal for pest control. I feel the way forward with pest control is the method of Integrated Pest Management (IPM). Although not fully successful, this form of pest control generally has more advantages than the conventional methods, and in the long run is more likely to be cost effective. With further research into new methods of integrated pest management, the environment is likely to be safer from damage, and pests will be under sustainable control. ...read more.

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