Rice water weevil demonstration program results – 2011

A portion of the rice water weevil field crew. From left to right: Anna Meszaros, Nick Colligan, Jordan Fryoux, Natalie Hummel, Jimmy Meaux and David Albano.

Rice water weevil (RWW) management demonstrations have been conducted for the past four field seasons. The purpose of these demonstrations is to evaluate currently recommended insecticides on commercial rice farms in Louisiana to control RWW. These trials are a joint effort between county agents, farmers, consultants, seed dealers and chemical distributors. In 2011, we compared three insecticide seed treatments (CruiserMaxx, Dermacor X-100 and NipsIt INSIDE) to an untreated check. Each treatment was planted in two strips at each location. A total of 6 locations were included in the 2011 demonstration test. The commercial farms were located in Acadia, Calcasieu, Evangeline, Jeff Davis, Rapides and St. Landry parishes. We took stand count data 2 weeks after seedling emergence at five locations and RWW core samples (10 cores / plot) 4 weeks after permanent flood to assess the relative efficacy of treatments at all 6 locations.

The on-farm demonstrations were conducted in the parishes indicated in purple.

At five of the six locations we planted the variety XL745. Thus, the seeding rates were low and the results of our study may not translate to field planted at a higher seeding rate (more than 25 pound seeding rates).

We found no significant difference between stand counts. Plant heights were significantly greater in CruiserMaxx and Nipsit INSIDE treatments than in Dermacor X-100. When we analyzed the RWW core sample data we found that all seed treatments had significantly fewer RWW larvae per core than the untreated check (average 12.9 RWW larvae/core). Dermacor X-100 (average of 2.5 rww larvae/core) provided the highest level of control, whereas Nipsit INSIDE (average 7.9 larvae/core) and CruiserMaxx (average 7.9 larvae/core) provided intermediate levels of control.

We conclude from these observations that if you are planting rice at low seeding rates (less than #25) and decide to use a neonicotinoid seed treatment (CruiserMaxx or Nipsit INSIDE) you should scout the field at the time of flood for the presence of rice water weevil adults. If you find a high population of rice water weevil adults, you may want to consider applying a pyrethroid to provide additional protection from rice water weevils. However, if you use Dermacor X-100, be aware that it does not provide protection against other early season pests such as thrips, aphids, and Colaspis.

This project was coordinated by Natalie Hummel, Anna Meszaros and Mike Stout. Thank you to all of our cooperators: LSU AgCenter County Agents: Barrett Courville, Trent Clark, Vince Deshotel, Rob Ferguson, Keith Fontenot, Matt Martin, Jimmy Meaux, Dusty Zaunbrecher; Rice farmers: Chris & Randy Dauzat, Charlie Fontenot, Johnny Hensgens, Kenneth LaHaye, Glen & Wes Simon, Mark Stelly, Bill Wild; Crop Consultants and Company Representatives: Rusty Elston, Dennis Fontenot, Kent Guillory, Rustin Gilder, Cullen Minter, Dean Reed, Randy Verret; our Field Crew: Nick Colligan, David Albano, Jordan Fryoux, Marty Frey and the rice station entomology crew. Finally, we could not have completed this project without the financial support of the Louisiana Rice Research Board, DuPont, Syngenta and Valent.

I’ll discuss these results in the rice winter meetings. How did the seed treatments look at your farm?

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Rice insecticide seed treatment options in 2011

This article is reprinted from the LSU AgCenter Rice Research Station newsletter.

Authors: Natalie Hummel and Michael Stout

Rice farmers in Louisiana who use seed treatments to manage insect pests in their fields have a choice of seed treatments in 2011: Dermacor™ X-100 (DuPont Crop Protection) and  CruiserMaxx® (Syngenta).  In addition, Valent has requested an experimental use permit (EUP) for NipsitInside seed treatment, an insecticidal seed treatment alternative similar to thiamethoxam.  If approved, NipsitInside will be used on a limited number of acres in Louisiana in 2011 and will potentially be available on a wider scale in 2012.  Although these three insecticidal seed treatments are similar in many respects, they also differ in key ways.  Understanding the similarities and differences between the two seed treatments is crucial to making the right insecticide choice for each rice field.

The key pest targeted by CruiserMaxx, Dermacor X-100, and NipsitInside is the rice water weevil, the most important early season insect pest of rice in Louisiana.  Dermacor X-100 has been evaluated against the rice water weevil in multiple small-plot tests over many years at the LSU AgCenter Rice Research Station in Crowley, and in addition has been used commercially in Louisiana the past three growing seasons.  Dermacor X-100 provides excellent control of rice water weevil larvae; in commercial fields, weevil populations were typically reduced by 90-95% compared to fields not treated for weevils.  CruiserMaxx has also been evaluated in multiple small-plot trials over the past several years at the Rice Research Station, and it too provides good control of rice water weevil larvae, although, in side-by-side comparisons of Dermacor X-100 and CruiserMaxx conducted in small plot trials at the Rice Research Station, control of weevil larvae given by CruiserMaxx is generally not as good as control given by Dermacor X-100.  In rice water weevil demonstration tests in commercial fields in 2010, we found that Dermacor X-100 provided the best level of weevil control, followed by pyrethroid (Karate pre, Karate pre + mustangMax on fertilizer post, or Karate post) and CruiserMaxx.  Dermacor X-100 provided significantly better control than the other two treatments.  There was no significant difference in weevil control between the pyrethroid and the CruiserMaxx seed treatment.  Unfortunately, the results from hybrid test plots (25 pound seeding rate) in 2010 did not provide any more clarity about the ability of CruiserMaxx to provide effective weevil control at the low seeding rates.  We plan to repeat the demonstration test again next season, particularly focusing on the low seeding rate question.  Small plot replicated research that may also clarify the question of effectiveness of CruiserMaxx at low seeding rates will also be conducted.  

Probably the most important difference between the three seed treatments is their activity against secondary pests.  Because these chemicals belong to different chemical classes (the active ingredient in Dermacor X-100 is a type of anthranilic diamide, whereas CruiserMaxx and NipsitInside are neonicotinoids), they are effective against different pests.  CruiserMaxx and NipsitInside will probably provide better control of colaspis larvae (present in a few fields in southwest Louisiana in 2009 and 2010) than will Dermacor X-100, and will also provide good early-season control of sucking insects such as aphids, thrips and chinch bugs.  Dermacor X-100, on the other hand, should provide excellent control of early-season Lepidopteran pests such as fall armwyorms.  Recent evidence from both Louisiana and Texas indicate that Dermacor X-100 provides protection against stem-boring insects.  Evidence from Texas also indicates that Dermacor X-100 may help control South American Rice Miner in rice.  The spectrum of pests controlled by each of these seed treatments is probably the most important consideration in choosing between the three.  As a related consideration, CruiserMaxx is marketed as part of a seed treatment “package” (CruiserMaxx® Rice) that includes fungicides that may help control seedling diseases and rice blast.

There are also similarities and differences in the agronomic practices that are used with each of these seed treatments.  Importantly, the use of both seed treatments is restricted to dry-seeded (drill-seeded or dry broadcast) rice; neither product can be used in water-seeded rice.  Also, the per-seed application rate of CruiserMaxx will not change with rice seeding rate, unlike Dermacor X-100, for which application rate is adjusted for seeding rate.  This may make CruiserMaxx easier to use, but it should be noted that the use of CruiserMaxx at very low seeding rates (for example, seeding rates typically used for hybrid rice varieties) has not always provided acceptable control in tests conducted by LSU AgCenter.  Details on the use patterns for NipsitInside are not known yet.

The expected availability of three seed treatments for insect control in rice, along with other available products for insect control (Karate, Mustang Max, and the other pyrethroids), gives Louisiana farmers a wide range of options for managing their insect pests in drill-seeded rice.  Unfortunately, there are not as many choices in water-seeded rice, and expanding the range of options for insect management in water-seeded rice is a continuing focus of research for the Entomology program.  

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NipsitInside seed treatment from Valent

Field meeting with Sumitomo and Valent Scientists. We toured Mike Stout's test plots at the rice research station in Crowley. Photo by Tiffany Pasco.

Valent has been working with Mike Stout and other university scientists across the US to develop a new insecticide seed treatment for rice water weevil management in rice.  This product is called NipsitInside and contains the active ingredient Clothianidin.  Clothianidin is a neonicotinoid insecticide.  The neonicotinoid class of insecticides also contains Thiomethoxam (the active ingredient in CruiserMaxx).  

Valent is pursuing a section 3 registration with NipsitInside in US rice production.  The current schedule projects possible registration by 2012.  In order to obtain more data to support the registration package, Valent is preparing to apply for an Experimental Use Permit (EUP) for this product on limited acreage in the delta region states.  This will include 3,000 to 5,000 acres in Louisiana, if the EUP is approved by the EPA.  Valent has applied for a saleable EUP.  If you are interested in planting some NipsitInside treated seed, you can contact Valent Representative John Bordlee for more information. 

If the EUP is approved, we plan to include NipsitInside in side-by-side comparison with Dermacor X-100 and CruiserMaxx in our demonstration test in 2011. 

If you’d like to know more about the efficacy of this product you can contact your local county agents, myself or Dr. Stout.

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Monitor your insecticide seed-treated fields.

The new seed treatments are a tool we have available in rice integrated pest managent.  The goal of these treatments is to prevent infestation by rice water weevil larvae.  The two treatments that are available provide variable levels of weevil control.  Historically, Dermacor X-100 has provided a better level of rice water weevil control than CruiserMaxx.  Dermacor typically provides about 95 to 98% control of rww larvae.  CruiserMaxx provides above 80% control.  With this difference in the level of control, it would not be surprising to see some larvae in bucket samples in infested fields.  This year we are evaluating Dermacor X-100 and CruiserMaxx in side-by-side commercial field evaluations.  The data are now coming in.

With a seed treatment it is best not to trust blindly that control will occur because you booked the seed treatment.  I have received a few reports of fields where there was a mix-up with the seed treatment.  The end result was that the seed treatment was not applied on the seed and a weevil infestation was not prevented.  In some cases, this was caught early enough to do something.  In other cases, the rice was past green ring and so there were no options for weevil management.

I’d like to remind everyone to take the time to scout and monitor even those fields that were treated with Dermacor X-100 or CruiserMaxx.  If you happen to find weevil larvae in your field, and you catch the infestation early enough you might need to drain the field.  There are a lot of variables that play into draining – maturity of the crop, time required to drain and reflood the field, availability of water to reflood, and weather conditions.  The LSU AgCenter is not confident in the ability of draining to manage an existing rww infestation, but sometimes this is a measure of last resort.  The research on draining has had mixed results.  We have one drained test plot this year, and Mike and I are discussing some possible research on draining in the future.

If you have fields where the seed treatment is not providing adequate control, please contact me or your local county agent to report the problem.  We are just beginning to take core samples from our test plots.  i will have some results from the core sampling available by next week.

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Update on Horton Site – water-seeded rww test in Vermilion Parish

Yesterday, County Agent Stuart Gauthier pulled core samples at the test site farmed by Alden Horton.  Alden wanted to really study the management of rice water weevils in a water-seeded system.  In this case, the only option for pesticide management is the use of pyrethroids.  The first step was to spend the time to scout properly before and after permanent flood for the presence of rice water weevil adults.  Stuart worked closely with Dr. Saichuk, myself and Alden to check the field on a regular basis – at least weekly, but often times more frequently.   It was a tough decision to decide on weevil management at this site. 

Permanent flood was applied on April 23, 2010. We scouted before flood, did not find weevils, so we decided to hold off on spraying.

On May 6, 2010, Stuart scouted the fields with Johnny and Alden.  At this time, the rice was at mid-tillering and rice water weevil adults (including mating pairs) were found in the field.  The population was sparse, but there are often many more that you don’t see.  We recommended an application of 2.0 fl oz of KarateZ.  Two small cuts that were separated by levees from the treated fields were left untreated for comparison.

We gathered 10 cores per field 4 weeks after permanent flood.  This is when you will see a peak in the population.  We processed the cores at the rice station yesterday – 10 cores per field – untreated and Karate treated.  In the untreated check, the average number of larvae per core was 4.8.  By comparison, the Karate treated field had a population of 0.9 larvae per core.  Much research has led us to conclude that each larvae can cause 0.5 to 1.5% yield loss.  Based on this estimate, we would predict that a yield loss from 2.4 to 7.2% may be experienced at this field site.  It appears that a treatment was called for at this location.

We’ll let you know how it looks as the season progresses.  We will probably have a stop here at the Vermilion Parish rice tour on July 6, 2010.

Our sincere thanks go to Mr. Alden Horton for cooperating in this demonstration test.

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Pyrethroid spray recommended at Vermilion Parish demo site

This morning I met with County Agent Stuart Gauthier, Rice producer Richard Hardee and Consultant Chuck Greene at the demonstration site in Vermilion Parish just outside of Gueydan. 

Meeting with cooperators Chuck Greene, Richard Hardee and County Agent Stuart Gauthier near Gueydan, La.

This part of the state is really hurting for water – I read the local paper where the headline was the extreme need for water.  Some parts of the parish had less than 1/2 inch of rain in April, and other areas had no measurable rain.  Compounding the lack of rain is the lack of fresh surface-water available.  The parish is still suffering from the effects of salt water intrusion caused by the hurricanes. 

Fortunately, Richard has access to a well, and we are completing the application of permanent flood on this site.  Mr. Greene walked the field with Richard last week to make the decision about a pyrethroid application before permanent flood.  Weevil scarring was not abundant in the field and he was hard-pressed to find an adult weevil.  The decision was made to wait for a pyrethroid application until after permanent flood.  Permanent flood is the trigger for rice water weevil adult oviposition (egg laying).  

Today we scouted the field that was slated to receive a pyrethroid application – if scouting determined it to be necessary.  We were able to find about 10 rww adults, 2 of which were a mating pair.  

Rice water weevil adult.

 

We also found an abundance of fresh feeding scars.  

Rice water weevil scars on a rice plant leaf.

 

Stuart also noted that many of the rww adults he found were below the surface of the water – these are probably females laying eggs.  

Chuck Greene and I discussed our options and decided a weevil treatment was needed.

 

Chuck and I discussed the situation with Richard and decided that a pyrethroid spray is now warranted.  We recommended between 1.7 and 2 fl oz per acre of Karate be applied sometime this week when the wind is calm (today was pretty windy).  We plan to go back in and scout in one week to make the decision about the need for a second application. 

Also at this site, we will possibly evaluate draining a cut to look at the effect of draining on rww population in an infested field.  I’ll keep you updated on how that goes.  We will take core samples in approximately 4 weeks to evaluate the insecticide treatments.(Photo credits: all photos taken by Anna Meszaros, LSU AgCenter.)

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Rice water weevil scarring observed in rice – start scouting early for early-season pests

When I was scouting for aphids in Ville Platte, I was surprized to observe rice water weevil adult scarring on the seedling rice.

Rice water weevil feeding scars on a rice leaf blade.

Close-up shot of rice water weevil adult feeding scars on rice.

This was observed at the LaHaye rww demonstration site in Ville Platte, La (Evangeline Parish).  These fields are a perfect location for weevils for a couple of reasons: 1) they are near a lot of bayou areas and 2) the field is bordered by a break of trees – nice overwintering habitat for weevils.  It’s not suprising that we are finding rww in these particular fields, but a little surprising to see adults are already moving into fields even in this cool weather.  I would encourage you to start scouting for weevil now, particularly in rice that is currently under pin-point flood, or will be flooded soon.  If adults are entering your field, and the rice is flooded, then egg laying can begin to occur early in the season.  The application of a pyrethroid early in the season is a judgement call that you will have to make based on your observations scouting.

Rice water weevil adult - LSU AgCenter photo.

If you planted seed treated with either CruiserMaxx or Dermacor X-100 seed treatment, then you do not need to make an insecticide application for rice water weevil management.  You do, however, need to scout for other early-season pests, such as aphids, chinch bugs, south american rice miner, leafminers and fall armyworm. 

CruiserMaxx should control the following early-season pests: aphids, chinch bugs, rice water weevil adults and larvae.

Dermacor X-100 should control the following early-season pests: south american rice miner, leafminers, fall armyworm, and rice water weevil larvae.

For pictures of these early-season pests, please refer to the Louisiana Rice Production Handbook by clicking here.  For management recommendations please refer to the Rice Varieties and Management Tips by clicking here.

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Planting demonstration sites in St. Landry and Evangeline Parish

Yesterday we planted two demonstration sites.  We started bright and early at Charlie Fontenot’s farm in St. Landry Parish.  Michael Fruge and Sunny Bottoms (both with Horizon Ag) brought their 20 foot Great Plains drill out to the site.  Vince Deshotel met me a the farm office and told me that he had received a call from Kent Guillory telling us that Dave Morein decided to plant his colaspis test site that afternoon.  So, it turned out to be a full day of rice planting. The weather could not have been better and the blue skies with white fluffy clouds were breathtaking.

Planting started with two passes of CL151 seed that was not treated with an insecticide.  This untreated area borders the field road and is next to a marshy area with trees.  There is a good chance that if weevils are overwintering, they will be found near this edge of the field.

After two passes of untreated seed, we cleaned out the drill, and loaded sacks of Dermacor X-100 treated CL151.  6 passes of Dermacor treated seed was planted at the 65 lb seeding rate.  The drill was cleaned out again and loaded up with CL151 treated with CruiserMaxx.  At this point, we started planting a seeding rate trial.  CL151 was planted at a variety of seeding rates.  This will give us a chance to evaluate CL151 at different seeding rates, and also the efficacy of CruiserMaxx at a variety of seeding rates.

This site was chosen because Charlie is suspicious that he experienced stand loss from Colaspis larvae damaging seedlings last season.  If the colaspis show up this season, we will be able to compare Dermacor X-100 and CruiserMaxx activity against this pest.  Also, in the past Charlie has treated with pyrethroids for weevil management.  We are curious to see what the rww population is typically like at this site.  Of course, this year may not be a typical year.  That remains to be seen.

I asked Charlie to call me when first emergence of seedlings is observed.  We’ll take observations on date of first emergence, and then stand counts and plant height 14 days after emergence.  If colaspis are a problem in this field, the damage will be observed in those first few weeks after emergence.

We left Charlie’s at about 11 am to head over to Evangeline Parish.  On the way Dave called, because there had been a break-down and planting would be delayed until about 2 or 3 pm.  No problem, we just took our time heading east.  When the time was right, we headed over to meet Dave Morein, Brian (Dave’s son who is now farming with him full-time), and Dennis Fontenot (Consultant).  When we pulled up dark clouds were threatening and rain started sprinkling lightly as we were planting the last field.

This series of fields is bordered on three sides by Miller Lake and a thick stand of trees.  Historically, there are high populations of rice water weevils.  Dennis had scouted this field site for us last season to monitor the adult colaspis in a field of beans next to a cut of rice that had substantial stand loss from colaspis damage.  In this test we will again compare an untreated check to CruiserMaxx and Dermacor X-100 seed treatment.

When we arrived, Dave had some Dermacor X-100 treated seed still loaded in the drill. left-over from planting another field.  We vacuumed out the hopper and loaded untreated seed.  This series of fields is planted in CLXL729 at a 25 lb seeding rate.  In our test, we are comparing an untreated field, and two passes on the south side of a neighboring cut (both are the high points in this area) to Dermacor X-100, and CruiserMaxx treated fields.

We will be scouting intensively during the first two weeks after emergence to see if the colaspis larvae overwintered and may cause damage in the rice.  Dennis had GPS marked his sampling sites in the untreated rice field and we will mark those with flags and sample the area for larvae.  It will be interesting to see if there is a relationship between the adult colaspis population in the soybeans last season, and the population of colapsis larvae in the  seedling rice this season.

I’m not sure what transpired with the rain that was just starting to come down when we left the field.  I’ll be checking in with Kenneth LaHaye this afternoon.  Tentative plans are to plant at the LaHaye farm in Evangeline Parish tomorrow.  Of course, it all depends on the weather.  We also may plant in Acadia, Concordia, and Evangeline Parish this week.

Sorry I did not include pictures, I need to load my download cable in my camera bag.  I’ll try to add pictures in the next few days.

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Acadia Parish Entomology Demonstration Sites

This morning I met County Agent Barrett Courville at the Acadia Parish Extension office.  Barrett grabbed his rubber boots and we headed out to meet with Mr. Rustin Gilder at the Hoffpauir farm.

County Agent Barrett Courville and Mr. Rustin Gilder discussing the rww demo at the Hoffpauir farm.

The Hoffpauir farm is located in southwest Rayne, LA.  The fields we will studying this season, are on the north side of the field road from the fields we evaluated in 2009.  This makes a unique opportunity to look at the weevil population over time.  This season we will compare CruiserMaxx, Dermacor X-100, pyrethroid to an untreated check.  We pulled up some of the field stakes from last season and I saw a nice little black and yellow snake – boy that will wake you up!

In Crowley, just south of I-10 we met with (left to right) Mr. Charlie Harmon, Barrett Courville, Jude Bellard, and Doug Leonards.

After wrapping up at the Hoffpauir farm, we headed over to meet with Crop Consultant Doug Leonards, and Farmers Charlie Harmon and Jude Ohlenforst.  Doug had identified some colaspis damage in a rice field just north of this series of fields that were planted in soybeans in 2009.  Doug scouted the bean field for colaspis adults and sent us samples throughout the season.  This year, the field will be planted into rice.  We decided to have a ten acre section treated with CruiserMaxx within this approximately 80 acre field.  If the colaspis cause a reduction in stand, we will be able to compare the untreated seedlings to those grown from CruiserMaxx treated seed.  We’ll also be noting date of first emergence, stand count, and plant height.  If there is a reduction in stand in the untreated area, we’ll pull cores before flood to see if we find colaspis larvae on the roots.

The Lawson family (left to right) Larry, Alan, and Colin with County Agent Barrett Courville in Crowley, LA.

Our final stop was to visit with the Lawson family about a test we will be putting out with Michael Fruge (Horizon Ag) and Steven Thevis (G&H).  I was delighted to meet three generations of current (and future) farmers.  Colin told me that he wants to be a farmer when he grows up, but his dad said that he needs to go to college first.  Well, he’s comfortable running around rice fields already.

At the Lawson farm, we will be putting out a test comparing CruiserMaxx to Dermacor and an untreated check.  Alan is fairly certain that he suffered some stand loss from colaspis larvae damaging roots in a nearby rice field.  The field we will work in this year was planted in beans, the stubble was plowed in the fall, then water was held until December when the land was water-leveled.  Water was held until late January, so for a period of about 3 months in total.  It will be interesting to see if colaspis have survived those conditions.

While we were standing in the field Alan walked around and picked up some debri.  It is odd to find that in a prepared rice field that is set-back from the road.  Alan pointed to a row of Oak trees where the leaves were all removed.

The oak trees in the middle of this break that have leaves removed, mark the path of a tornado that destroyed 10 homes, and narrowly passed the Lawson home.

These trees mark the path of a tornado that passed through this rice field on Christmas Eve, 2009.  10 homes were destroyed, and Alan witnessed the tornado picking up and throwing debris at his house.  Debri was strewn across the rice field as well.  Amazingly, no one was injured.  I don’t think the tornado would have effected the colaspis, we can only hope…

The weather was perfect today – this rice field was firm enough to walk on.  If the weather holds, a lot of rice will be planted in the next week.  The first rice was water-planted in Jeff-Davis Parish last Friday.

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