Driven by farmers' expectations of higher yields, savings in management
time, and lower pesticide costs, the adoption of first-generation
genetically engineered (GE) crop varieties with enhanced input traits
has increased rapidly despite consumer resistance in some countries.
About 200 million acres of GE crops with traits for herbicide tolerance
(HT) and insect resistance (Bt) were grown worldwide in 2004, and
U.S. acreage accounts for 59 percent of this amount.
Adoption of GE soybeans, corn, and cotton by U.S. farmers has climbed most years since these varieties became available commercially in 1996. HT crops survive certain potent herbicides, allowing adopters of these varieties to control pervasive weeds more easily. HT soybean adoption has expanded most rapidly and widely, averaging 87 percent of soybean acreage in 2005, followed by HT cotton, at 61 percent of cotton acreage.
Bt crops contain a gene from the soil bacterium Bacillus thuringiensis
(Bt) that produces a protein toxic to specific insects. Use of Bt
crops is concentrated in areas with high levels of infestations
of targeted pests, so acreage shares of Bt corn and cotton are lower
than for HT soybeans and cotton, and vary more across States. Bt
cotton, which controls tobacco budworm, bollworm, and pink bollworm,
was planted on 52 percent of cotton acreage in 2005—ranging
from 13 percent in California to 85 percent in Louisiana. Acreage
share of Bt corn flattened during 1999-2002 because farmers had
already adopted on the acreage where protection against the European
corn borer was needed most. Use of Bt corn expanded recently, reaching
35 percent in 2005, following the introduction of a new Bt variety
to control the corn rootworm.
ERS research has shown that U.S. farmers are realizing tangible economic benefits from adopting these GE crops through higher yields, lower pesticide costs, and savings in management time. The impacts of GE crops vary with several factors, including pest infestations, seed price premiums, prices of alternative pest control programs, and any premiums paid for segregated crops.
In addition to corn, soybeans, and cotton, U.S. farmers adopted HT canola and virus-resistant papaya and squash. Two GE crops (delayed-ripening tomatoes and Bt potatoes) introduced in the mid-1990s were withdrawn from the market years later due to marketing problems.
Other biotech crops are in various stages of development. For
example, USDA's Animal and Plant Health Inspection Service has approved
field testing for crops with resistance to virus, fungi, cold, drought,
and salinity; crops that increase protein and oil content and produce
naturally decaffeinated coffee; and crops with added vitamins and
iron.
Download PDF version