Purdue weed scientists explain rapid growth of Palmer amaranth
This year Purdue University decided to get serious about keeping an eye on our Palmer amaranth and placed a trail camera at our Cass county site to take pictures of the weeds every five minutes. The camera has been positioned to take pictures of two plots - one with a residual herbicide application and one without, from planting until Mid July.
The first couple of weeks did not provide many great pictures as the Palmer amaranth slowly emerged in the unseasonably cold and rainy weather of mid-May.
The week of May 30 through June 6, however, provided warm temperatures and timely rain events that promoted rapid growth of Palmer amaranth from small seedlings to 4 to 6-inch plants. In a week's time the Palmer has gone from a very manageable weed to a weed that may only be marginally controlled with our available post-emergence herbicides.
Given another week or rather a few days the Palmer will likely be at an unmanageable growth stage.
The pictures will eventually be formatted in a time-lapse video to show the advantages of using a pre emergence herbicide as well the growth rate of Palmer amaranth.
The impressiveness of this past week of photos has prompted us to give you a sneak peak with two photos taken one week apart, when the Palmer amaranth went from about 1 to 1.5-inches in height to 5 to 6-inches in height in the plot that did not receive a pre-emergence herbicide.
Also note that the plot on the right that did receive a pre-emergence herbicide is still clean and free of Palmer amaranth pressure.