Below is a picture of yellow nutsedge exhibiting two characteristics that contribute to its ability to be a serious pest. The “nut” part of its common name is derived from the structure shown at lower left. It is not a nut, but is actually a tuber, an enlarged part of the rhizome. The white, root-like structures are also rhizomes which are underground stems. If the stems were above ground they would be called stolons. These structures are underground and well protected from herbicide sprays. To really get to them requires a good translocated herbicide. If you plow and cut the tuber off from the main plant it just produces a new plant from the tuber. The plant can also produce lots of viable seed enabling it to survive by more than one method. One way to distinguish yellow nutsedge from purple nutsedge is to cut the tuber and smell it. If it has a petroleum odor it is purple nutsedge. Purple nutsedge also has a more blunt leaf tip than yellow nutsedge. The tubers of purple nutsedge are hairy compared to the fairly smooth yellow nutsedge tubers. Yellow nutsedge is actually sold as Chufa to be used in wildlife food plots. Apparently turkey will scratch up the tubers and eat them. One biologist said he found the crop of Teal killed in a rice field full of the tubers. If they would leave the rice seeds alone and selectively consume the tubers it sure would help.
Below are three photographs taken in the same field where Command had been applied with a ground rig. The applicator made one pass on each end to provide a turn around area. Then he started making linear passes from the east side of the field working his way to the west. In the top photograph the clearly damaged area on the right is the first pass. The green area is the east half of the field. The bare area across the top of the picture is the west side of the field. We could not determine if there was some extremely odd mixing problem that caused a light to normal dose to be applied at the beginning then a heavy rate later as more product mixed or if there was some sort of mechanical malfuntion in the spray rig. It does have electronic spray controllers so I suppose it is possible that caused the strange injury pattern. The severly damaged area will have to be replanted. This is the most severe Command injury I have ever seen.