Agriculture Reference
In-Depth Information
28
There is some indication of emergence of Bt-resistant corn rootworm in some parts of the Corn
Belt http://www. bloomberg.com/news/2012-09-04/-mounting-evidence-of-bug-resistant-
corn-seen-by-epa.html. http://bulletin.ipm. illinois.edu/article.php?id=1704. There is also
anecdotal evidence that resistance is a contributing factor to increasing corn insecticide
sales in 2012 and 2013 (I. Berry;
WSJ
, May 21, 2013). Tabashnik et al. (2013) recently
analyzed 77 studies carried out in 5 continents from 1996 to 2012. They find that “although
most pest populations remained susceptible, reduced efficacy of Bt crops caused by field-
evolved resistance has been reported now for some populations of 5 of 13 major pest
species examined, compared with resistant populations of only one pest species in 2005.”
They conclude that “the increase in documented cases of resistance likely reflects increases
in the area planted to Bt crops, the cumulative duration of pest exposure to Bt crops, the
number of pest populations exposed and improved monitoring efforts.” They also conclude
that while “regulations in the United States and elsewhere mandate refuges of non-Bt host
plants for some Bt crops, farmer compliance is not uniformly high and the required refuge
percentages may not always be large enough to achieve the desired delays in evolution of
resistance. Both in theory and practice, using Bt crops in combination with other tactics as
part of integrated pest management may be especially effective for delaying pest
resistance.”
29
A dominant trait will be expressed in progeny if at least one of the parents has the gene for that
trait. A recessive trait will be inherited if both parents have the gene for that trait. (Hedrick,
2000).
30
According to Andow et al. (2008), “a structured refuge is one that is planted near Bt cotton
deliberately and an unstructured refuge relies on the other crops already grown as part of the
local cropping system and where Bt is not used.”
31
Impending expiration of glyphosate patent protection in 2000 and the availability of generic
glyphosate herbicides have led to a decrease in its price since 1998.
32
Dauer et al. (2009) provide empirical evidence that horseweeds, one of the more important
glyphosate-resistant weed species, can disperse between farms.
33
BMPs include applying multiple herbicides with different modes of action at the recommended
rates and developmental stages for the target weeds in the field, increasing the intensity of
tillage to reduce the fraction of seeds that germinate, planting weed-free crop seed, scouting
fields routinely, cleaning equipment to reduce the rate of introducing weeds to other fields,
and preventing weed introductions by maintaining field borders (Norsworthy et al., 2012).
34
Glyphosate resistance in weed species and biotypes in the United States is also due to
glyphosate use in tree orchards, on roadsides, and on non-HT crops, where it is used before
crops are planted and after they are harvested.
35
Many farmers incorrectly assume there is no need to adopt BMPs because new herbicides will
be available in the future (Norsworthy et al. 2012). In addition, the benefits of using BMPs
occur in the future and are uncertain, as opposed to the certain increase in production costs.
36
More information about this program is available at https://www.roundupreadyplus.com/Pages/
Home.aspx.
37
Non-GE foods can be more expensive if they cost more to produce, or if marketing streams
must be kept separate.
38
Consumers who asked about the GE fruit were told that it contained genes that caused it to
produce a natural insecticide. GE fruit is not commercially available in these countries, and
consumers who expressed surprise about this were told the fruit may have come from an
experimental orchard (Mather et al., 2011).
39
The supermarket chain Whole Foods has announced a labeling policy that will be implemented
by 2018 to indicate if their products contain GE ingredients (http://media.
wholefoodsmarket.com/news/whole-foods-market-commits-to-fullgmo-transparency). ERS
researchers discuss the economic issues related to food labeling, including GE foods (Golan
et al., 2001).
40
Tesco, ASDA, Sainsbury's, and William Morrison.
