The report notes that although two types of insects have developed resistance to Bt, there have been few economic or agronomic consequences from resistance. Practices to prevent insects from developing resistance should continue, such as an EPA-mandated strategy that requires farmers to plant a certain amount of conventional plants alongside Bt plants in "refuge" areas.
Economic and social effects
In many cases, farmers who have adopted the use of GE crops have either lower production costs or higher yields, or sometimes both, due to more cost-effective weed and insect control and fewer losses from insect damage, the report says. Although these farmers have gained such economic benefits, more research is needed on the extent to which these advantages will change as pests adapt to GE crops, other countries adopt genetic engineering technology, and more GE traits are incorporated into existing and new crops.
The higher costs associated with GE seeds are not always offset financially by lower production costs or higher yields, the report notes. For example, farmers in areas with fewer weed and pest problems may not have as much improvement in terms of reducing crop losses. Even so, studies show that farmers value the greater flexibility in pesticide spraying that GE crops provide and the increased safety for workers from less exposure to harmful pesticides.
The economic effects of GE crops on farmers who grow organic and conventional crops also need further study, the report says. For instance, organic farmers are profiting by marketing their crops as free of GE traits, but their crops' value could be jeopardized if genes from GE crops flow to non-GE varieties through cross-pollination or seed mingling.
Farmers have not been adversely affected by the proprietary terms involved in patent-protected GE seeds, the report says. However, some farmers have expressed concern that consolidation of the
|Contact: Jennifer Walsh|
National Academy of Sciences