Weeds cause a major loss each year in the United States in terms of quality
and quantity. The importance of weeds to crop production will continue eve
n with genetically modified crops due to shifts in weed species. Discussion
of losses will be devoted to soybean. The yield loss in soybean can be gre
ater than 80% and for highest and most economical yield potential, weeds mu
st be removed by 2 to 3 weeks after crop emergence. To continue a high leve
l of soybean production, the producer must have variable weed control optio
ns available. Thus, varied herbicide modes of action and cultural practices
must be maintained. To prevent future losses, the Food Quality Protection
Act (FQPA) is providing a stringent health-based standard on herbicides.