Positive Environmental Issues

1. Reduced Pesticide Usage
   Reduced pesticide usage is one of the benefits of genetically modified crops that are pest resistant. Currently, genetically modified pest resistant crops include Bt cotton, Bt corn, Bt sweet corn, Bt potatoes, and virus resistant squash. These crops are able to resist certain pests and need fewer pesticide sprays. In the past, pesticide usage on cotton, sweet corn and potatoes has been very high with some of these crops requiring more than a dozen insecticide sprays per season. However, Bt sweet corn needs less than 15 percent of the insecticide sprays than those traditional varieties.But Bt crops still do need some insecticide sprays. Bt is very selective and only controls some insects, and the protection provided by the Bt only protects against some pests. So while Bt crops are protected from the primary pests, control of secondary pests may sometimes require the use of insecticide sprays.
   
2. GM Crops Compliment Biological Control
   One group of non-target organisms that need to be encouraged is the natural enemies of our crop pests. Natural enemies are composed of a wide array of parasitic and predatory insects and other arthropods. Control of crop pests by natural enemies is referred to as biological control. Unfortunately, biological control cannot prevent crop damage in all circumstances and farmers often need to apply pesticide sprays.When these sprays include non-selective insecticides, the natural enemy populations are often hurt more than the pest that needed controlling. The reason is that while the pesticide may kill both the pest and its natural enemies, by killing the pest it has also eliminated the food source that the natural enemy populations will need to recover. Because of this, it often takes much longer for the natural enemy populations to recover than the pest population. In the absence of natural enemies, pest populations are able to increase much more rapidly. This can result in greater reliance on pesticide sprays after the natural enemies are eliminated.Genetically modified crops that produce their own plant pesticides are more compatible with biological control. The plant pesticides are more selective than most insecticide sprays.In addition, because the need fewer pesticide applications, they preserve natural enemies populations and are more compatible with biological control.
   
3. Plant Pesticides Impact less on Non-target Organisms
   Genetically modified plants that produce their own plant pesticides include Bt cotton, Bt corn, Bt sweet corn, and Bt potatoes. These plant pesticides are very selective, for example, the type of Bt in Bt corn only controls the caterpillars of some moths and butterflies. The type of Bt in Bt potatoes controls Colorado potato beetles. In addition, the Bt is inside the plant, so only insects that feed on the plant or plant parts are exposed to the plant pesticide. An exception to this is with the pollen from Bt corn which is wind blown. The Bt-corn pollen also contains the Bt toxin. It has been shown in the laboratory to reduce the survival of monarch caterpillars that have been feed on milkweed plants that were dusted with this pollen.But it is important to keep in mind that these genetically modified crops that produce their own plant pesticides require fewer pesticide sprays. Most of the commonly used insecticides used on these crops are referred to as broad spectrum insecticides. They are generally as toxic to non-target organisms as they are to the target pest. Plants that produce their own plant pesticides are more selective in terms of controlling pests without damaging non-target organisms. Their impact on non-target organisms is further reduced because they require fewer broad spectrum pesticide sprays.
   
4. Increased Yields, Reducing the Need to Expand Agricultural Acreage
   While the genetically modified crops on the market today do not increase yields. For example, the GM crops that produce their own plant pesticides do not yield more than traditional varieties; they just protect the plants from yield loss. Differences in yield do not represent the ability of the plant to produce more. In fact, in the absence of pests, these hybrids should have yields equal to comparable to traditional hybrids.However, GM crops that increase yields are under development and the future looks very promising. Unless yield increases are able to keep in pace with population growth, more land will be need to be devoted to commercial agriculture. Current tends show that the amount of prime agricultural land available is decreasing. Crop yields may need to increase by 20 to 40 percent in the next 20 years in order feed an expanding population. Biotechnology provides some of the tools needed to continue to increase the yields of the world's important staple crops.
5. Issue: Some GM Crops May Reduce Soil Erosion
   New herbicide resistant crops may help to reduce soil erosion. There is a need to prevent soil erosion in order to maintain farm sustainability and to reduce pollution of streams, rivers and wetlands. This allows the producer greater flexibility in terms of when to control weeds. Rather than using reemergence herbicides that may need to incorporated into the soil, these are applied over the crop and the weeds as they are actively growing. GM herbicide resistant crops are compatible with and encourage no-till agriculture.