What is a primary drawback to planting transgenic crops?

The emergence of secondary pest problems is a significant concern when planting transgenic crops, particularly those engineered for pest resistance. These crops often target specific pests, which can lead to a decrease in those pest populations. However, as the primary pest is controlled, secondary pests that were previously kept in check can proliferate without their natural competitors. This can result in new pest problems that farmers may not have encountered before, necessitating additional measures to manage these secondary pests, such as increased pesticide applications or changes in pest management strategies.

In contrast, the other options highlight either benefits or misconceptions associated with transgenic crops that do not align with the challenges they present. The assertion of higher yield with no additional costs overlooks the potential need for increased pest management or agronomic adjustments. A decrease in overall pest resistance would not typically be associated with the introduction of transgenic crops, which are designed to enhance resistance to specific pests. Lastly, the claim of lower environmental impact does not universally apply, as the environmental effects can vary widely depending on various factors, including pest management practices employed and the specific crops used.