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8. Consider Insect-resistant Crop Varieties

checking young plants

Plants have many natural mechanisms to keep insects at bay: repellent or toxic chemicals, thorns, hairs, and tough roots and stems. Seed companies try to tap into these mechanisms when developing crop varieties. But like everything else, there are pros and cons to using resistant varieties.

Resistant varieties will not interfere with other pest-management techniques such as crop rotation or, if needed, an insecticide application. They are usually the same price or only slightly more expensive than other seeds. And they may reduce the need for certain insecticide treatments, reducing costs and protecting water quality.

checking corn However, resistant varieties are usually only resistant to one or a limited number of pests. When resistant crops are being developed, some positive traits may be lost while other traits are strengthened. Some resistant varieties spend more of their resources protecting themselves; subsequently, their yields may drop. Also, if resistant varieties are widespread and insect densities high, insects may develop new strains that are not affected by the plant's defenses.
researcher New techniques in genetic engineering now allow the transfer of genes from one species to another, which could result in the quicker development of pest-resistant varieties. For instance, researchers recently used gene transfer techniques to develop corn varieties that contain the Bacillus thuringiensis, or Bt, toxin. Bt is a bacterium that is toxic to some insects, but not to people or animals, and has been used as a rescue insecticide against first-generation corn borer.
checking corn While these techniques offer the possibility of dramatic advances, if corn varieties containing a Bt toxin are used extensively, European corn borer populations may develop resistance to this specific insecticidal compound.
checking corn To slow down the corn borers' development of resistance to Bt, maintain "refuges"—areas where the corn borers are not exposed to the Bt toxin.
moth If any corn borers survive in the Bt-corn fields, you will want to increase the odds that these surviving moths will mate with moths emerging from the refuges. A refuge includes all corn fields without Bt corn, as well as fields with other plant species on which corn borers can develop.

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