Arkansas Rice Update 6-17-22

by Jarrod Hardke, Rice Extension Agronomist - June 17, 2022

Arkansas Rice Update 2022-13

June 17, 2022

Jarrod Hardke, Scott Stiles, Trent Roberts, Tommy Butts, Nick Bateman, and Ben Thrash

“In the summertime, when the weather is hot, you can stretch right up and touch the sky.”

Some Like it Hot

Jarrod Hardke

We’re having a heat wave, a tropical heat wave.  Close the door, you’re letting the bought air out.

So we talked last week about wanting to go fast, but maybe we could slow down just a little there, Ricky Bobby.  The heat is now into overdrive, and while the rice is moving fast, it’s now impossible to stay caught up to it.  A minor cooldown is expected on Sunday (88!), so you get that while you’re working on Father’s Day, but the majority of next week is full of 99-101 depending on where you’re standing.  But let’s be honest, at that point what’s a degree here or there?

We are still two weeks away from the 4^th of July, but this heat has me already looking toward that date for particular reason.  We have long considered getting a “4^th of July rain” – really meaning a rain somewhere in that timeframe – as being make or break for getting us through the season.  Given this early heat and dry conditions, getting an upcoming rain sometime in the next couple of weeks will be extremely critical – both for keeping up with rice water and for having water for our other crops.

A bit of good news is that so far, we’re not really hearing anything on disease pressure.  So we’ve got that going for us.  Stay hydrated out there and take plenty of breaks – nothing will get done if you overheat, it’s not worth it.  Work through the morning, take a break during the hottest part of the day, then do some more in the evening.  We all know this, but reminders never hurt.

Let us know if we can help.

New on Arkansas Row Crops Radio this week:

Weeds AR Wild Series, S2 Ep 17:  Optimizing Rogue Activity in Rice

Fig. 1.  NOAA 7-day precipitation forecast.

Delayed Phytotoxicity Syndrome (DPS)

Jarrod Hardke

A common theme over the past couple of weeks has been calls about delayed phytotoxicity syndrome (DPS) – sometimes called delayed phytotoxic shock.  Ultimately the rice is sick, and its from our herbicides that are usually safe.

The symptoms of DPS are patchy areas of rice that are dark and stunted with twisted and/or rolled leaves (onion-leaf).  You may also see “fish-hooking” of tillers near the base of the plant and affected tissue will be very rigid.  When conditions get very severe, the plants feel “crunchy” or stiff and brittle – you can feel it when you step on them.

Common herbicides such as Bolero, Facet, and Propanil are the main culprits, but others can be involved.  Why?  After flooding, when the soil goes anaerobic, fungi alter the normally safe herbicides and make them toxic to the rice.

The only real solution to getting these areas to recover is to drop the flood.  Getting oxygen back into the soil and to the plant roots is what will alleviate the problem and allow rice to grow out of it.  The more severe the injury, the more you will have to dry the field up.

There has been nothing to suggest that this affects particular cultivars.  While we don’t do any screening for it – we’ve observed it on hybrids and varieties alike.  Management, soil conditions, and environmental conditions play a role in whether it shows up and how severely.

Fig. 2.  Delayed phytotoxicity syndrome (DPS) from herbicides applied to rice.

Rice Water Weevil Activity is Booming

Nick Bateman and Ben Thrash

Over the past two weeks we have received multiple phone calls on rice water weevil (RWW) showing up in large numbers in rice that has just gone to flood.  We are seeing the same thing in our plots at Stuttgart, however not near to level of some the fields we have walked in the north part of the prairie or in northeast Arkansas this week.  Keep in mind if you have a diamide seed treatment (Fortenza or Dermacor) I would not spray for weevils; however, if your seed treatment is a noenicitinoid (CruiserMaxx Rice or NipsIt), odds are you are outside of the 28-35 days after planting window to get good control of RWW.

When scouting for RWW and trying to decide if an insecticide application is warranted, there are a few things we need to keep in mind.  These are:  1) how long have I been flooded, 2) is there scarring on the newest leaf material, and 3) are adults present.

How long the permanent flood has been established before RWW move into the field can determine if we need to spray.  From what we have seen the past few years is that if we have been flooded for 15-21 days or longer before RWW move into the field, then the yield loss is far less than if they move into the field immediately after flooding.

Leaf scarring from adult RWW does not cause yield loss but is rather an indicator that we have adult weevils in the field.  When scouting for RWW we need to look at the newest leaf material to determine how recent the feeding occurred.  Keep in mind that leaf scarring does not always correlate with the number of larvae present in the field.  This is why we prefer to look at leaf scars and adults to make a treatment determination.

RWW adults are going to typically move into a rice field as soon as the flood is established.  Once in the field, it only takes the adults 3-7 days to mate and lay eggs.  Once eggs are laid, there aren’t many options left for control.  If we see scarring but no adults present, then an insecticide application at that point will not be beneficial.  If adults are present and easy to find this may warrant a foliar application.

As far as control goes, you only have a few options.  If an insecticide is needed, lambda (Lambda-Cy) is about your only option.  As far as a preflood vs postflood timing, we have seen better control from a preflood standpoint.  With that being said, these are small plot tests that we can flood up in a matter of hours versus days.  I would bet on a field that is going to take multiple days to flood, that most of the insecticide if not all will be broken down before the flood can be established.  As a last resort, but a very effective treatment for RWW (however not the most economical), fields can be drained to soil cracking.  This will kill the larvae and help protect yield.

If you have any questions feel free to reach out to us.

Watching for Post-Flood Potassium Deficiency

Jarrod Hardke and Trent Roberts

Much of the rice in the state has now gone to flood, and the majority of remaining acres will be getting there quickly.  A common issue that we see every year as rice reaches reproductive growth (internode elongation) is potassium (potash) or K deficiency.

When we fertilize and flood rice the rapid vegetative growth and significant increases in biomass over a relatively short period of time can lead to nutrient imbalances or deficiencies.  The 3-4 weeks after flooding are the time period when K demand is the highest and we are most likely to see deficiency symptoms appear.

Potassium deficiencies are rarely diagnosed preflood as the plant demand is relatively low.  However, K is required by the rice plant in near equal amounts as nitrogen (N) and is important for many processes associated with water relations, metabolic functions, and the plant’s ability to fight disease.  Soil testing is the first step in proper K management.  Current K rate recommendations based on soil test K levels are very reliable and can help identify and prevent K deficiencies before they ever occur.

However, there are some cases where soil tests are not taken, or K was not applied preplant and K deficiencies can present themselves in both subtle and dramatic fashion.  This year, increased fertilizer prices also led to the use of reduced K-fertilizer rates, which can increase the chances of observing a K deficiency.  Since K is a mobile plant nutrient the deficiency symptoms in rice will appear on the oldest, lower leaves first and will be characterized as marginal leaf chlorosis that moves from the tip of the rice leaf towards the collar.  “Hidden hunger” continues to be a real concern.

Hidden hunger for potash is essentially a K nutrient deficiency that does reduce yield, but goes undiagnosed due to a lack of obvious nutrient deficiency symptoms or mischaracterization of the deficiency as normal leaf senescence (lower leaf drop) due to lack of sunlight, etc.  Proper identification of K deficiency requires you to push the plant canopy back and really focus on those lower older leaves much like you would do when scouting for sheath blight.

In extreme cases (and what we observe in research) is that K deficient rice seems to be shorter and struggling to really take off after preflood or midseason application of N then hidden hunger or K deficiency may be occurring.  The most common timing for K deficiency in rice is immediately after midseason N applications.

If K deficiency is identified, 100 lb potash per acre (60 units K₂O per acre) is recommended at the first onset of symptoms and yield can be salvaged all the way until the late-boot growth stage.  Timing of K application is critical with earlier identification of the deficiency and application of K to deficient rice leading to higher yield potential.

One way to identify potential K deficiencies is with a Y-leaf tissue sample – which is the leaf blade of the uppermost collared leaf on the rice plant.  Fifteen to twenty Y-leaves are required to have enough sample to complete the analysis and should be collected from the entire field or area of interest.  Recent research on using Y-leaf tissue potassium concentration indicates that >1.6% tissue K is optimal from green ring through mid-boot.  Our goal should be to keep the Y-leaf tissue K concentrations above 1.6% during this timeframe.

If you are concerned about K deficiency, a tissue test may help identify potential hidden hunger.  Please remember that there is a wide window of opportunity for successful application of K from preplant to late-boot, but the earlier a potential K deficiency is identified the larger the return on investment.

Fig. 3.  Rice leaves showing potassium deficiency.

Herbicide Max Use Rates and Cut-Off Timings

Tommy Butts

A large portion of the rice in the state is now reaching or already at flood and moving into reproductive growth stages.  As a result, it’s important to remember cut-off timings and season max use rates for herbicide applications.  Applications of herbicides above season use rates or occurring after cut-off dates can result in rice injury and yield loss.  Table 1 provides this information as a quick reference for postemergence rice herbicides.  For additional information regarding max season use rates and cut-off timings of other herbicides or for other cropping systems, check out the MP566 Application Cut-Off Timings for Common Herbicides and MP567 Max Use Rates per Application and per Season for Common Herbicides.  Good luck out there!

Table 1. Rice herbicide cut-off timings and season max use rates.

Rice Market Update

Scott Stiles

New crop rice futures started the week higher with double digit gains Monday and Tuesday.  On a 9-cent loss, the September contract closed at $16.72 ½ Thursday (6/16).  Basis remains firm with fall delivery bids at mills ranging from 9 to 14 cents per bushel under September futures.  Basis at driers is generally 20 to 27 cents per bushel under futures for fall ’22 delivery.

Fig. 4.  CME September ’22 Rough Rice Futures, Daily Chart.

There were some encouraging findings in this week’s Export Sales report.  Long-grain rough rice sales and shipments hit 16-week highs for the week ending June 9^th.  Strong sales were noted to Mexico and Panama.  Last week’s export volumes were an encouraging sign the pullback in U.S. prices over the past month may be uncovering some demand.

The renewed sales strength is welcome as long-grain rough rice sales are 22% behind last year’s pace.  A year ago, the U.S. had made large volume sales to Brazil and Venezuela.  No sales to Brazil have been made in the current marketing year.  By this point last year, the U.S. had also sold over 271,000 mt of rough rice to Venezuela compared to just 27,500 tons today.  Furthermore, sales to our largest buyer Mexico are down 17% from last year.

Long-grain milled rice sales were also strong last week, reaching a marketing year high of 40,853 mt.  Of note, sales to Haiti of 22,420 mt were the highest since February 3^rd of this year.  Marketing year to date, long-grain milled rice sales are running 28% ahead of last year.  However, much of these gains can be attributed to the 120,010 mt sold to Iraq.  No further sales to Iraq have been made since November 2021.

With seven (7) reporting weeks left in the 21/22 marketing year, old crop export sales need to remain strong.  In the June WASDE, USDA lowered old crop exports by 1 million cwt. to 63 million.  This equates to a 3.2% decline from the 20/21 marketing year.  As of June 9^th, total long-grain sales are running 8% behind last year.  Without consistently strong sales and shipments for the remainder of this marketing year, old crop exports risk a downward adjustment to 60 million cwt.

Table 2. U.S. Long-Grain Rice, Supply and Demand.

Source: USDA, June 2022.

Juneteenth Holiday Trading Hours

Sunday, June 19

• No evening trading session.

Monday, June 20 (Juneteeth Observed)

• CME Group CLOSED for daytime operations.

• Evening trading for grains resumes at 7:00 p.m. CST

Tuesday, June 21

• Grains trade normal hours.

DD50 Rice Management Program is Live

The DD50 Rice Management Program is live and ready for fields to be enrolled for the 2022 season.  All log-in and producer information has been retained from the 2021 season, so if you used the program last year you can log in just as you did last year.  Log in and enroll fields on the DD50 website.  

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.