Recent Trends in GE Adoption
Herbicide-tolerant (HT) crops, developed to
survive application of specific herbicides that previously would
have destroyed the crop along with the targeted weeds, provide
farmers with a broader variety of options for effective weed
control. Based on USDA survey data, HT soybeans went from 17
percent of U.S. soybean acreage in 1997 to 68 percent in 2001 and
93 percent in 2012. Plantings of HT cotton expanded from about 10
percent of U.S. acreage in 1997 to 56 percent in 2001 and 80
percent in 2012. The adoption of HT corn, which had been slower in
previous years, has accelerated, reaching 73 percent of U.S. corn
acreage in 2012.
Insect-resistant crops containing the gene from
the soil bacterium Bt (Bacillus thuringiensis) have been available
for corn and cotton since 1996. These bacteria produce a protein
that is toxic to specific insects, protecting the plant over its
entire life. Plantings of Bt corn grew from about 8 percent of U.S.
corn acreage in 1997 to 26 percent in 1999, then fell to 19 percent
in 2000 and 2001, before climbing to 29 percent in 2003 and 67
percent in 2012. The increases in acreage share in recent years may
be largely due to the commercial introduction in 2003/04 of a new
Bt corn variety that is resistant to the corn rootworm, a pest that
may be more destructive to corn yield than the European corn borer,
which was previously the only pest targeted by Bt corn. Plantings
of Bt cotton expanded more rapidly, from 15 percent of U.S. cotton
acreage in 1997 to 37 percent in 2001 and 77 percent in 2012.
Use of Bt corn will likely continue to fluctuate over time,
based on expected infestation levels of European corn borer (ECB),
and the corn rootworm which are the main pests targeted by Bt corn.
Similarly, adoption of Bt cotton depends on the expected
infestation of Bt target pests, such as the tobacco budworm, the
bollworm, and the pink bollworm. Adoption appears to have reached
the low-growth phase, as adoption has already occurred on acreage
where Bt protection is needed most. Insects have not posed major
problems for soybeans, so insect-resistant varieties have not been
developed.
These figures include adoption of "stacked" varieties of cotton
and corn, which have both HT and Bt traits. Adoption of stacked
varieties has accelerated in recent years. Stacked cotton reached
63 percent of cotton plantings in 2012. Plantings of stacked corn
made up 52 percent of corn acres in 2012.
Adoption of all GE cotton, taking into account the acreage with
either or both HT and Bt traits, reached 94 percent of cotton
acreage in 2012, versus 93 percent for soybeans (soybeans have only
HT varieties). Adoption of all biotech corn accounted for 88
percent of corn acreage in 2012.