|21 December 2018
THIRD WORLD NETWORK BIOSAFETY INFORMATION SERVICE
Dear Friends and Colleagues
Widespread Damage from Dicamba Drives a Deep Wedge Between Farmers
Dicamba was first registered in the U.S. in 1967. Known to be volatile, becoming vapor at high temperatures, it was typically only used to clear fields of weeds before planting in late fall or early winter—at times when it would do little damage to nearby plants and didn’t impact growing crops. New formulations, introduced by Monsanto (now Bayer), Dupont and BASF in 2016 and 2017, claimed to lower dicamba’s volatility, and therefore its drift potential, in warm spring and summer weather. Dicamba use has increased in conjunction with crops genetically engineered to be resistant to it, such as soya and cotton. However, farmers and even homeowners have reported serious damage to vegetables especially tomatoes, trees, gardens, shrubs and lawns.
The issue has divided farming communities and set neighbour against neighbour. Pro-dicamba farmers argue it is the only thing that can fight herbicide-resistant “superweeds,” such as waterhemp and marestail. But because dicamba mimics plant hormones called auxins, it is also toxic to a wide variety of broadleaf and woody plants. While specialty crops like fruit and vegetables have no defense against pesticide drift, the risk of damage has motivated soybean farmers to adopt dicamba-resistant soybeans to avoid their own losses.
Until now, farmers have explored a range of options—some have settled disputes themselves, others have sued Bayer, and many have filed insurance claims. One dispute ended in deathand an unknown number have resulted in bitter relations. In sparsely populated areas, where neighbors have often relied heavily on one another in the past, these dynamics can have large ramifications on daily life. A chasm has opened up that is hard to repair.
Despite these escalating tensions, planting of Bayer’s genetically engineered Xtend dicamba-resistant soybeans doubled in acreage, to 50 million acres, in 2018. The situation only promises to get more complicated now that the Environmental Protection Agency has reauthorized dicamba’s registration for two more years with additional restrictions, including requiring it be sprayed only by certified applicators up to 45 or 60 days after planting on cotton and soybeans respectively, introducing buffers to protect endangered species and restricting application hours during the day. However, many pesticide and weed experts don’t think the EPA’s new directives will do much to get dicamba damage down to an acceptable level. The restrictions don’t prevent late-season spraying. In addition, research has shown that glyphosate can increase the volatility of dicamba, yet there are no new regulations that prevent mixing the two in pesticide spray tanks.
With best wishes,