Everybody has heard of Round Up Ready technology and a lot of people think that it is great. And it is great. However, there are certain limitations to the technology that people should be aware of. Glyphosate (Roundup, Touchdown) is what is known as a burndown herbicide. The molecule is absorbed through foliage and is translocated to the growing points of the weed where it inhibits amino acid synthesis. Because it requires growing plant tissue to work, glyphosate has no residual effect. So, any weeds that emerge after glyphosate is applied are safe from its effects. This means that multiple applications of glyphosate are usually required to keeps crop areas free of weed. Weed control can be greatly improved by combining glyphosate (or another burndown herbicide) with a chemical (such as atrazine or S-metolachlor) that has residual action. This system not only kills weeds that are present, but prevents the germination and emergence of other weeds. Now remember that certain chemicals are labeled for certain crops, so be sure that you read the label before applying anything. Also note that glyphosate technology only works with crops that are specifically engineered to be resistant to glyphosate. So if you are going use glyphosate on your corn, make sure that it is glyphosate tolerant or your will be very sorry.
Take Care,
John