You know the old adage "timing is everything." It applies to herbicides too. As the bird conservation director for Audubon Arkansas, I understand the need for herbicides to control weeds in the name of bird habitat protection. So I'm sympathetic to the farmers who use them to protect their crops and our food.

But there is an effort currently underway to change the timing of when one especially potent herbicide can be applied that will have serious repercussions for bird habitat and crop production in Arkansas.

I am talking about a currently proposed rule change at the Arkansas Plant Board that would extend the use of dicamba further into Arkansas' warm growing season. Dicamba has been used for decades in winter to control weeds before commodity crops are sown. However, Monsanto recently began selling genetically modified soybean and cotton varieties that are dicamba-resistant, meaning they can be sprayed during the growing season to control weeds without damaging the crop.

The problem is dicamba is highly volatile in warm temperatures, meaning the liquid becomes a poisonous gas that spreads in all directions. Volatility increases with temperature, so spraying later in the season means that damage to non-GMO crops and bird habitat will occur days later and miles away from where applied.

University of Arkansas weed scientist Dr. Jason Norsworthy told the state Plant Board in December that if every soybean and cotton farmer in Mississippi County grows Monsanto's dicamba-resistant variety, no other type of sensitive crops will be able to grow anywhere in that county because there will be so much dicamba in the air. That is bad news for farmers growing tomatoes, peanuts, and sweet potatoes, and ruinous for any organic farming operations.

But this issue shouldn't just be of concern to farmers.

As a scientist and conservationist, I'm worried about the unintended consequences and the impact to street trees and home gardens in Blytheville. I'm worried about Monarchs, bees, and other pollinators, many of which are already in steep decline, trying to find food to complete their life cycle. I'm extremely worried about harm to Big Lake National Wildlife Refuge and Big Lake Wildlife Management Area, which are popular with duck hunters, and which Audubon recognizes as Important Bird Areas (IBA). I'm concerned about collateral damage to the 14 other IBAs, and the birds they harbor, in all the other counties where soybean and cotton are intensively grown.

The science is clear that dicamba's volatility makes it a serious threat for agriculture and the environment when used in warm weather conditions. Sadly, despite the science the Plant Board moved forward with a proposal to extend the use of dicamba to May 21.

Fortunately, this rule change is not final. There is something you can do to help. A 30-day public comment period is open through Feb. 5, followed by a public hearing on Feb. 20, concerning this proposal. I would urge you to tell the Plant Board to follow the science and vote no on this proposal! Find the online comment form and details about the hearing on Audubon Arkansas' website at ar.audubon.org/dicamba.

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Dr. Dan Scheiman is bird conservation director at Audubon Arkansas, established in 2000 as a state office of the National Audubon Society.

Editorial on 01/31/2019