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.
Originally posted by Dr. Natalie Hummel LSU AgCenter Extension Entomologist on her Louisiana Rice Insects blog. The link to the original article can be found here: http://louisianariceinsects.wordpress.com/2012/04/17/colaspis-strike-concordia-parish-rice/
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.
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.
Last year I wrote the first edition of Rice Field Notes one month earlier than this year. In spite of the much warmer weather (hottest March since record keeping began in 1895), much of the crop is later than last year.
The photo below was taken in our verification field in Cameron parish and is a good example of why it is late.
The intention here was to drill seed. Each time it got almost dry enough to drill, it rained. In desperation we decided to vibrashank and broadcast seed. As you can see it had gotten pretty hairy with weeds in the interim. Nearby water seeded rice kept us from hitting it with glyphosate.
By the following Monday rice was up or coming up. A lot of emergence is occurring in 5 to 7 days when we normally expect 10 days to call it. By that time we could have drilled, but would have been a week behind. Based on the data generated by Dr. Steve Linscombe last year a week later could mean a significant drop in yield. We’ll just have to see how it goes.
You can link to Dr. Natalie Hummel’s weblog by going to: http://louisianariceinsects.wordpress.com/
This article was originally published in Louisiana Farm and Ranch, February 2012. I’m reposting it here for your information. This is an important article to read as growers are making their decision about insecticide seed treatments in rice for the 2012 season.
Authors: Natalie Hummel, Associate Professor and Assistant to the Director & Mike Stout, Professor
We have had quite a few inquiries about using a combination of seed treatments, neonicotinoid and Dermacor X-100, in rice. While this practice is legal, using more than one seed treatment is not a practice that we encourage in most circumstances because it results in more insecticide use in rice production than may be necessary.
The rice industry is considering one of these combinations of seed treatments: 1) Dermacor X-100 and CruiserMaxx or 2) Dermacor X-100 and NipsitINSIDE. Typically, a combination of seed treatments is only being considered when planting rice at low seeding rates, primarily because of concerns about the lack of efficacy of CruiserMaxx and NipsitINSIDE at hybrid seeding rates (25 lbs/acre or less) that we have observed in our rice water weevil demonstration trials and small plot trials. The second scenario is where Dermacor X-100 is being used for rice water weevil management and there is a history of stand reduction because of a sporadic pest infestation, usually chinch bugs or armyworms. Combining seed treatments provides a benefit of protecting the crop from injury by some primary and sporadic crop pests.
As the rice industry moves toward a more sustainable crop production profile, the LSU AgCenter strongly encourages rice producers to be good stewards of these insecticide seed treatments. Stewardship of these seed treatments means avoiding the use of insecticides not needed in the crop. For this reason, we discourage the widespread use of a combination of insecticide seed treatments in rice. We instead encourage the person making the seed treatment decision to consider the spectrum of pests that each insecticide can control, the seeding rate, and the history of crop pests in that field.
It is important to remember that each of the seed treatments controls a different group of insects. Dermacor X-100 belongs to a class of insecticides called anthranilic diamides, which target a specific receptor in the muscle of the insect. Dermacor X-100 is registered to control rice water weevil larvae, borers (Mexican rice borer, Rice stalk borer, Sugarcane borer), armyworms and colaspis (2ee registration for suppression). CruiserMaxx and NipsitINSIDE are both neonicotinoid insecticides that affect the nervous system of target insects. CruiserMaxx is labeled to control rice water weevils (larvae and adults), chinch bugs, colaspis and thrips. NipsitINSIDE is labeled to control rice water weevils and colaspis. We do not have data to support the ability of CruiserMaxx or NipsitINSIDE to control chinch bugs, colaspis or thrips in Louisiana, but we anticipate that they will control these pests based on observations from other crops and from rice in other parts of the world. As you study these seed treatments, you can see how a combination of these products can control most of the insects that attack rice in Louisiana. This is part of the reason why there is an inclination toward using a combination of treatments.
Here are criteria for you to consider as you make your seed treatment decision. The first is the seeding rate. This needs to be considered because neonicotinoids don’t always provide good control of rice water weevils at low seeding rates. Dermacor X-100 does provide control of rice water weevils at all seeding rates, but it will not control chinch bugs or thrips. According to the chemical manufacturers, neonicotinoids do control other early season pests including chinch bugs, thrips and colaspis. Another challenge at low seeding rates is that the plant stand is thin and is less tolerant to any insects that reduce the stand by killing seedlings. Insects that can reduce the plant stand count include armyworms, chinch bugs, colaspis and thrips. Borers can infest fields after the plant is at the green ring growth stage and reduce yields by causing deadhearts and whiteheads. Remember that if you put out a combination of seed treatments for a sporadic pest and that pest doesn’t infest your field, then you didn’t need to use a combination of seed treatments. We have data that indicate that rice water weevils infest more than 90% of rice fields in Louisiana. This justifies the use of a seed treatment to control rice water weevils as part of a good IPM program. That is not the case for many of our sporadic pests (armyworms, chinch bugs, colaspis, borers, etc.), which rarely occur at levels that justify treatment. Also, keep in mind that we rarely recommend an insecticide treatment for thrips in rice; usually the damage is not severe enough to require an insecticide.
Here are a couple of situations where a combination of seed treatments may be a good management decision. If you are planting rice at a low seeding rate and you anticipate that you will have an infestation of chinch bugs that would justify a pyrethroid treatment, then a combination of seed treatments would be a good option. In this situation, you would be using Dermacor X-100 to control rice water weevils, borers and armyworms and adding a neonicotinoid to control chinch bugs or thrips. Also, if you are planting rice at conventional seeding rates and you are using a neonicotinoid seed treatment to control rice water weevils and colaspis, but you typically have problems with armyworms or borers, then you may want to apply Dermacor X-100 to your seed.
There is one more thing to consider as you make your seed treatment decisions for the 2012 season. The EPA recently approved a Section 24C (special local need) registration for use of Dermacor X-100 in water-seeded rice. If you are interested in this option, a certified seed treater can provide more information. Remember that you CANNOT use the other seed treatments (CruiserMaxx or NipsitINSIDE) in water-seeded rice. The use of CruiserMaxx and NipsitINSIDE in water-seeded rice is illegal and will not provide control of the target pests.
If you have any questions about the seed treatment options registered for use in rice, please contact your local County Agent, or Natalie Hummel (email@example.com) for more information.