Arkansas Rice Update 6-2-23

by Jarrod Hardke, Rice Extension Agronomist - June 2, 2023

Arkansas Rice Update 2023-11

June 2, 2023

Jarrod Hardke, Tommy Butts, Nick Bateman, and Ben Thrash

"I says, 'Pig Pen, this here’s the Rubber Duck and I’m about to put the hammer down.'”

Covered Up in Dust

How do you spell relief?  R-A-I-N.  Suddenly there appears to be a chance of scattered storms this evening across the delta.  I don’t know where the chances came from and I don’t care.  Bring it on.

As it stands right now, we’re just at the start of May and it seems as though we’re already into conditions similar to mid-June last year.  Most of the state is 2-3 weeks removed from any appreciable rainfall.  Given the abundance of rainfall through April its not a shock that we have some extended breaks in rain, but this is an awfully early start to a dry summer.

In 2018 we turned very hot to start May and stayed that way through summer.  But it was humid and scattered showers were still a thing.  This year with winds out of the north and dry air, the scattered rains have stayed away.  A change toward southern winds and increased humidity are hopefully in store to help bring back chances of scattered storms.

There’s talk of El Nino taking hold which can lead to increased rainfall in the southern U.S.  Let’s hope that transition occurs, and we reap those benefits.  Otherwise, this stands to be a 2022 summer drought redux.

As reminder / repeat from last week – herbicide injury responses are up.  Routine herbicide applications made at normal rates to seemingly healthy rice are causing more injury response than usual.  Stressed rice of any kind is going to increase that occurrence.  Right now, that stress is hot and dry with dry north winds.  Add herbicides to rice that isn’t really growing, then add nitrogen and water (especially cold water) and you’re going to see crop response.

As a general rule, under these conditions, I’m not in favor of actively removing water from fields.  Water in the field is a precious commodity right now.  To drop the flood right now, we only need to wait a few days and it will do it for us.  This will help with rice recovery.  Only in extreme injury situations do we need to consider actually pulling the water and that needs to be on a case-by-case basis.

Some of these responses can create what appear to be deficiency symptoms – but it’s really the crop response that’s to blame and nutrient levels are fine once the response is corrected.

Avoid making quick kneejerk reactions – these lead to us falling down.

Let us know if we can help.

Fig. 1.  NOAA 7-day precipitation forecast.

Table 1. U.S. Rice Planting Progress as of May 28, 2023 (USDA-NASS).

Watch Out for ALS Injury

Tommy Butts

It’s that time of year when we are spraying a lot of ALS-inhibitor herbicides across our rice acres.  We have tough and large barnyardgrass out there we’re trying to get ahead of with Regiment.  We also have yellow nutsedge stragglers, hemp sesbania (coffeebean), jointvetch, smartweed, and other problematic broadleaves that we need to get rid of before the flood or we reach herbicide cutoff timings that we’re applying Permit, Permit Plus, or Gambit for.  These herbicides are all excellent options for managing the weeds we’re targeting.  However, these ALS chemistries can severely impact neighboring crops.  And this year more than ever, we have diverse cropping systems all emerged and planted directly adjacent to each other.

ALS herbicide injury results in several distinct injury symptoms.  Bottle-brushed roots (Fig. 2) and stacking of internodes (Fig. 3) are symptoms of ALS injury (like Newpath) in corn.  Red/purple veins (Fig. 4) and chlorosis on the youngest (newest) leaves (Fig. 5) are symptoms that can occur on soybean and cotton.

Corn is extremely tolerant to Permit, Permit Plus, and Gambit (in fact, these herbicides are actually labeled for use in corn), as well as being tolerant to Grasp; however, Regiment and Newpath/Preface drift is extremely damaging to emerged corn.  Cotton is sensitive to all ALS herbicides used in rice.  Soybean is tolerant to Newpath/Preface; however, is moderately sensitive to Permit and Permit Plus and extremely sensitive to Grasp, Regiment, and Gambit.  Sulfonylurea-tolerant soybeans (STS) provide a safety net and are tolerant to Permit and Permit Plus; however, it needs to be noted that STS beans do not provide satisfactory tolerance to Grasp, Regiment, or Gambit (significant injury will still occur from a drift event of any of these three herbicides).

Overall, we just need to be aware of the potential injury and level of severity from these rice ALS-inhibiting herbicides.  They are essential tools in our rice weed control toolbox, but we need to safely apply them to continue using them in the future.  Let’s play as many games as we can to mitigate drift, i.e., use drift reduction adjuvants when necessary, use a larger droplet size if in areas of concern, make sure wind direction is blowing away from sensitive crops, and leave buffer areas/trim up on a different day when the wind direction shifts.

As always, if you have any questions, please let us know. And good luck out there!

Fig. 2. Bottle-brushed roots from ALS injury.

Fig. 3. Stacked internodes from ALS injury.

Fig. 4. Red/purplish veins on the underside of a soybean leaf from ALS injury.

Fig. 5. Chlorosis on new leaves from ALS injury.

ALS Flashing in Rice

Jarrod Hardke

One standout right now as a lot of rice is flooded up is rice “flashing” from ALS herbicide applications (such as Permit).  I usually refer to it as a “highlighter yellow” flash, which based on that color alone usually differentiates it from other possible issues (Fig. 6).  Also, the lack of a pattern is the pattern – it’s usually a mottled look and you may be able to pick out some tillage or wheel track marks breaking it up.  Often the roots take on a “bottle-brushed” appearance in most affected areas (Fig. 7)

We often associate ALS flash with cooler, wet years, but right now the extreme stress rice is under from hot and dry is generating a similar response.  Once the fertilizer and water hits the plants they seem to be trying to grow faster than they can deal with the herbicide.

The rice will most often grow out of it on its own.  Sometimes we’ll need to let the flood naturally back off to aid in recovery.  And in rare instances we may be forced to drain some areas if injury becomes extreme – usually just getting it back to a muddy state is enough.

Unless we have to, or accidentally, dry the field up too much where we fear some nitrogen may have been lost, there is no need to add more fertilizer.  It’s still there, the plants just need time to recover to take up what we’ve already given them.

Fig. 6.  ALS flashing in rice.

Fig. 7.  Bottle-brushed rice roots from ALS injury.

Rice Water Weevils are Increasing

Nick Bateman and Ben Thrash

As we start getting rice to flood, we will begin to attract rice water weevils.  Our rice water weevil plots in Stuttgart went to flood last week, and rice water weevil activity has increased dramatically this week over last week.  Generally, at the Stuttgart location rice water weevil pressure is low to moderate in most years.  Looking at these plots this week compared to previous years; rice water weevil pressure is higher than it was last year.  It is still too early to determine how bad rice water weevil will be this year, but in the past several years we have noticed that the rice water weevil pressure has initially been light when flooded before June 1^st and picks up considerable after.

The bulk of rice planted in Arkansas is either treated with NipsIt or CruiserMaxx seed treatment, which are excellent on grape colaspis.  However, efficacy of these products on rice water weevil decreases 28-35 days after planting.  Although rice water weevil pressure is higher for later planted rice, these plantings typically experience rapid growth allowing us to flood within 3 weeks of planting.  In these situations, we still get sufficient control of rice water weevil with NipsIt or CruiserMaxx.  If rice has been treated with Dermacor or Fortenza, it will still have protection from rice water weevil at least 60 days after planting.  Also, it is important to note that NipsIt and Cruiser within the 28-35 days after planting will reduce scarring observed.  However, Dermacor and Fortenza will not affect scarring but will maintain better control of larvae.

For rice that is going to flood past the 28-35 day window with CruiserMaxx Rice or NipsIt, a foliar application of a pyrethroid like Mustang Max, Lambda-Cy, or Declare might be called for.  However, Dermacor and Fortenza will NOT need a foliar application.  While scarring from adult weevil feeding is usually superficial and doesn’t cause yield loss, this is a sign that adults are present and active in the field.  Scarring can be used to determine if a foliar application is warranted.  In general, an application is warranted if over 50% of new leaves have scarring present.

Timing is critical on foliar applications for rice water weevil.  Applications must be made within 5-7 days of permanent flood establishment, as long as adults are present.  If it is later than that, our studies indicate you may as well keep the insecticide in the jug.  Your only option then is to drain the field until the soil cracks to prevent weevil damage.  Most growers aren’t crazy about doing that as it is costly and may impact weed control and fertility.  Remember, late rice will have high populations of rice water weevil and staying vigilant with scouting and timely applications will be critical.

Fig. 8.  Rice water weevil adult feeding on rice.

Fig. 9.  Leaf scarring from rice water weevil adult feeding.

Chinch Bugs Control Options in Rice

Nick Bateman and Ben Thrash

Over the past seven days we have received several calls on chinch bugs in rice.  This isn’t uncommon in hot dry years.  The common theme for most of these calls has been fields with large amounts of residue still present at planting, no insecticide seed treatment, or fields close to wheat.  Chinch bugs will hide under residue or right below the soil surface during the heat of the day then come out at night to feed.  This makes scouting for chinch bug somewhat difficult.  Looking for stressed areas in fields is a good place to start.  Flipping over residue and checking at the base of rice plants is the most likely areas to find them.

With the lack of rain in recent weeks fields are beginning to become more stressed.  This is when chinch bug can injure rice the most.  In many cases chinch bugs will out right kill rice plants in small areas of fields.  If this happens and these areas need replanted, use seed treated with either CruiserMaxx Rice or NipsIt Inside.  Both products will provide good control of chinch bug.

If replanting is not needed but control is still warranted pyrethroids (Warrior II or Mustang Maxx) do a good job.  We would suggest making these applications late in the evening as close to dark as possible.  This will increase the odds of good control.  In some cases, flooding the field will provide good control of chinch bugs as well.  This will be dependent on how quickly fields can be flooded.  If it takes multiple days and plants are showing signs of injury, flooding may not be the solution.

Keep an eye out for stressed areas of fields, fields near wheat, or that have heavy residue in them.  These are all likely places for chinch bug.  While chinch bugs typically don’t affect a large area in a given field, they can destroy small areas in a short window.

Call us if you need us.

Fig. 10.  Dead rice from chinch bug feeding in a field in Northeast AR (Mike Simmons).

Fig. 11.  Left to Right: Chinch bug nymphs on a rice leaf, dead rice plantfrom chinch bug feeding, and chinch bug nymphs hiding below the soil (Mike Simmons)

DD50 Rice Management Program is Live

The DD50 Rice Management Program is live and ready for fields to be enrolled for the 2023 season.  All log-in and producer information has been retained from the 2022 season, so if you used the program last year you can log in just as you did last year.  Log in and enroll fields here:  https://dd50.uada.edu.

Use the Arkansas Rice Advisor Internet App!

The Arkansas Rice Advisor site https://riceadvisor.uada.edu functions like an app on your mobile device.  There you can readily access the DD50 program, rice seeding rate calculator, drill calibration, fertilizer and N rate calculators, publications, and more.

Additional Information

Arkansas Rice Updates are published periodically to provide timely information and recommendations for rice production in Arkansas.  If you would like to be added to this email list, please send your request to rice@uada.edu.

This information will also be posted to the Arkansas Row Crops blog (http://www.arkansas-crops.com/) where additional information from Extension specialists can be found.

More information on rice production, including access to all publications and reports, can be found at http://www.uaex.uada.edu/rice.

Acknowledgements

We sincerely appreciate the support for this publication provided by the rice farmers of Arkansas and administered by the Arkansas Rice Research and Promotion Board.

The authors greatly appreciate the feedback and contributions of all growers, county agents, consultants, and rice industry stakeholders.