AskTFD: Do GMOs Reduce the Use of Round-Up?

Shannon asked: 

I keep hearing that: 1. Roundup ready crops enable farmers to drench/overuse roundup; and 2. Roundup ready crops enable farmers to use less roundup. From personal experience, I know Roundup is expensive and it doesn’t make sense that a farmer would want to use an excessive amount. Can you clear this inconsistency up? Thanks!

Shannon,

This is an excellent question! First, let me assure you that farmers definitely do not “drench” or “douse” our crops in Round-Up or any other pesticide, herbicide, or insecticide. Not only would such use probably violate all sorts of EPA regulations, it would also be wasteful, expensive, and pointless. As Sarah at Nurse Loves Farmers explained in her post about this, we apply about one pop can of Round-Up to an acre. Round-Up is diluted with a whole lot of water. So if you have seen crops being sprayed, most of that mixture is actually water being applied.

As to your second point – this is a fairly common concern. While it is true that the use of Round-Up has increased due to genetically modified crops, the overall use of pesticides and other types of herbicides has decreased.

Let me explain.

First, let’s acknowledge that weeds are a big problem for farmers, especially in row crops like soybeans and corn. A field that’s full of weeds is going to have lower yields and the crop itself may be of a lower quality. That’s because the weeds in the field compete with the crop plant for nutrients and resources. Unfortunately, many weeds are pretty aggressive and can easily crowd out crop plants. Considering that plants stay in one place, they only have a limited amount of resources available to them in that particular spot. If the weed is sucking up all the nutrients, that leaves a lot less for the crop. Hence, lower yields and quality.

Weeds can also be problematic when harvesting. Not only can the weeds get mixed in with the crop, they can also clog up our equipment. Trust me, it isn’t fun to have to stop the combine, get out, and clear the machine of excess weeds!

But that’s where Round-Up, or its active ingredient glyphosate, come in handy. Many of the widely used genetically modified crops today were developed to be resistant to glyphosate. That means that when Round-Up is applied to the plant it won’t kill it. On the other hand, plants that have not been engineered to have a resistance to glyphosate will die if the chemical is applied to it. As you can probably guess, that includes those pesky weeds in the field.

In the past, farmers had to apply several different types of herbicides in order to effectively kill the weeds. With the advent of GM crops, most of those other herbicides have been replaced with Round-Up. Hence, while the amount of glyphosate used has increased, there has been an overall decrease in the use of other herbicides. For example, one study that was recently published found that there has been a 37% decrease in the amount of pesticides used as a result of GM crops.

Also keep in mind that glyphosate is definitely not the most toxic chemical available. In fact, as a comparison to a homemade weed killer demonstrated, glyphosate turned out to be less toxic than vinegar.

By the way, a similar question was also answered on GMO Answers by two experts in the field. You can read their answers here and here.

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