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.
As I mentioned last week, ducks have been doing quite a bit of damage in water seeded rice in south Louisiana. Some farmers who have a lifetime of experience in lower Vermilion parish have told me they have never seen Teal down here this late and in these numbers. In our verification field pictured below it was a mixture of Teal and Black Bellied Whistling Ducks. After publishing last week’s Field Notes I was contacted by personnel at the USDA/APHIS Animal Damage Control office in Crowley. They wanted to know about the Black Bellied Whistlers because they too have noted a huge increase in their numbers this year.
The left most photograph shows an overall view of the field. The areas that appear to be clear water are slightly deeper (very slightly) areas that the ducks found more attractive. There is some rice remaining as can be seen in the second photograph which can be compared the third photograph of the green areas. The grower applied Avipel treated seed after last week’s visit and that seemed to run the ducks out. Others have told me it did not deter Teal. Reports are fairly constant that the product definitely works on blackbirds.
It was too late to start over. We will just have to live with the situation and hope some of the seed treated with Avipel add a little to the stand
Last week we were called to a hybrid rice field where there were issues with stand loss. We could not determine any specific cause, but did note the presence of thrips on nearly every plant. While the number was fairly large there presence was not especially alarming to me because I have always seen them on seedling rice. The field was treated with Dermacor which is not expected to control thrips. We also suspected some seedling disease. In the past we planted at high enough seeding rates to compensate for seedling loss, but the low seeding rates of hybrids magnifies any stand loss. Without a definitive cause we could only make a couple of suggestions; apply an insecticide or add some starter nitrogen. I followed up with the farmer who said he chose to add starter fertilizer and while the stand is still thin the seedlings are growing better. Nearby crawfish ponds may have had some influence on the decision.
We have not had to recommend an insecticide to control adult rice water weevils in several years, but yesterday we were called to a field where I took these pictures. They were in a field of water seeded Cheniere that was drained, but still damp at the time of the visit. The heavy feeding pressure is very evident as was some seedling disease.
The combination of the two was resulting in seedling death and stand reduction. To add insult to injury, the field had been hammered by hail about a week before. It was clear the plants could not take much more. Ironically, the field was planted with Dermacor treated seed which will control the larvae very well while having little to no impact on the adults.
There were so many adult weevils that while kneeling down in one spot I was able to count no less than 5 weevils. We could find them on the soil moving from plant to plant in the middle of the day when they are usually hiding in cracks in the soil. The farmer mentioned he had been under some security lights a few nights before and he had seen thousands of weevils flying around. We recommended a foliar insecticide.
Our verification field in Vermilion parish is presenting several problems which will make for an interesting and challenging year. It is a field with a history of Newpath resistant rice, both red and outcrosses. It was left fallow last year and plowed several times. This year we water seeded Cheniere. As many farmers are experiencing this year, water seeded fields are being decimated by ducks. Most of the farmers I have talked to say Teal are the primary problem, but in our field it is Black Bellied Whistling ducks. I have never seen that many together. Wednesday morning there were well in excess of 100 in a 40 acre block. Any ridge or edge of the field has accumulated the evidence of their feeding as can be seen in the accompanying photograph. One farmer told us that he cannot keep his propane guns going because neighbors turn them off at night.
The accompanying photograph is of Command injury to drilled Cheniere. The farmer applied the herbicide himself using a well calibrated ground rig. He was able to associate the injury pattern with the first pass of each of two loads he applied that day. We discussed the situation with Henry Stefanski, the FMC representative in an effort to understand why it happened. The problem likely occurred in the process of loading the spray rig. Command 3ME is heavier than water. If the agitator was not running when the herbicide was added to the tank even though there was water in the tank the herbicide settled to the bottom of the tank where a larger dose was drawn into the sump and boom before it could be mixed thoroughly. Thus the first pass of spray contained a higher than desired dose of herbicide resulting in the injury. It also means the remainder of the area sprayed probably has less than the intended amount applied to it.
Even though there is considerable bleaching, long term consequences are not expected to be severe. We recommended that he keep the field moist, but not establish a flood until the new leaves are coming out green. It also means no other herbicides can be applied until recovery is observed. In this case the direct effects may not be as great as the indirect especially if broadleaf weed pressure becomes heavy before recovery is evident.
Vermilion Rice Grower, Dwight Hardee of Gueydan is taking part in a field demonstration of the N-Sta*R test. His 15-acre field is divided into three nitrogen treatments based on
University of Arkansas nitrogen soil test recommendations.
Treatment 1: 95% relative yield–65 units of Nitrogen
Treatment 2: 100% relative yield–95 units of Nitrogen
Treatment 3: Standard Farmer Practice–95 units of Nitrogen plus an
additional nitrogen application at green ring
–2/9/12: burn down with 1.5 pt 2,4-D, and 1 qt. roundup
–3/7/12: no-til drill planted into bean stubble CL151 at 50 lbs to the acre. Seed was treated with dermacor/cruiser/fungicide/AV1011
-3/26/12: 4.5 qts RiceBeaux, 6 oz command, 9 oz newpath
4/10/12– 6 oz command, 4 oz newpath, 1 oz permit Fertilizer applied
(took 4 days to flood)
Urea was treated with N-fix.
All 3 plots received 150 lbs DAP 18-46-0 and 150 lbs of Potassium
Urea was used to make up the remaining nitrogen required.
(83lbs–95% and 150 lbs–100%)
I will keep you updated on the progress of the plots. We hope to visit
the plots at the Vermilion Rice Field Day scheduled for Thursday, July
5th, 2012. We will keep track of the yields when the plots are
harvested. The plots are just to the west of the Hardee drier on
Burnell Road in Gueydan.
Over the weekend Sebe Brown scouted a field in Concordia parish where the stand was being severely reduced by colaspis larvae feeding on seedlings. Problems with this field started on March 16 when the stand began to decline. The plants were described as yellow and stunted. This was a Dermacor X-100 treated hybrid rice field no-till drill-planted at a 23 lbs/acre seeding rate. Surrounding fields were growing nicely. When Sebe scouted the field on Saturday he confirmed that the injury was being caused by Colaspis larvae feeding on the roots of seedlings. The stand was reduced about 40% by this injury. The recommendation was made to establish a shallow permanent flood to avoid further injury. In a situation like this, where the rice isn’t quite ready for a flood, you may lose some injured plants to the flood. The alternative is to wait to establish flood, during which time the colaspis will continue to injure the seedlings and further reduce the stand. Establishment of a flood on the field will prevent further feeding injury by the colaspis larvae and eventually the larvae will die. Note: according to experts in Arkansas it may take up to a month for colaspis larvae to die in the permanent flood. Click here to read more about colaspis. You can watch a video on how to scout for colaspis here. The Dermacor X-100 should provide about 30% suppression of the colaspis infestation. Next season, they will consider using a CruiserMaxx or NipsitInside seed treatment to target control of colaspis. The use of pyrethroids will not provide control of colaspis because they are injuring the crop below the soil line.
Here are a few of the more prominent broadleaf weeds in the Cameron verification field.
The predominant grass is barnyardgrass. However,
the most troublesome grass is Creeping Rivergrass. I did not bother photographing the grasses this time. The variety planted is Cheniere so weed control is going to be a challenge. We will keep you informed of our progress.
We expected our verification field in Vermilion parish to test us because it has a history of Newpath resistant red rice and volunteer hybrid rice. It was fallow last year and was water seeded this year. The photo at right shows red rice seedlings that are already growing well in spite of having been worked in the water and water seeded.
An overview of the field is portrayed below. Rice was a day or so from emergence. We plan to fertilize and flood as soon as possible. The only other option would have been to try to apply glyphosate and start over.
Nearby rice, the late date, and poor results from trying that in the past eliminated that idea. I am afraid we will have an ugly field before it is over.
I know the field conditions are not the best for fertilizer application, especially nitrogen, but that is one of the limitations of pinpoint flood water management.