Arkansas Rice Update 7-2-21

by Jarrod Hardke, Rice Extension Agronomist - July 2, 2021

Arkansas Rice Update 2021-16

July 2, 2021

Jarrod Hardke, Trent Roberts, Nick Bateman, Gus Lorenz, Ben Thrash, Scott Stiles, and Yeshi Wamishe

“When you’re hot, you’re hot, and when you’re not, you’re not, put all the money in and let’s roll’em again, when you’re hot you’re hot.”

Summer Continues

Jarrod Hardke

Parts of the state received scattered rainfall amounts yesterday mainly in the northeast, which was very welcome by those that caught it.  However, there were more ‘have-nots’ than ‘haves’ with this event.  Little measurable rainfall has been received in recent weeks, making it more difficult to keep up with irrigation and for some to finish planting soybeans.  An old rice farmer from my area years ago was fond of saying, “be patient and wait on the rain we usually get around the 4^th of July, but if you don’t get it you’re a plucked chicken.”  Only he didn’t say plucked.

Certainly, none of us are looking for a really big rain, and too frequent rains will crank up disease pressure that we don’t want or need.  It would be nice to get a couple inches across the entire Delta and get us into a better place overall with crop management though and start steering this ship through to heading.  The current 7-day outlook won’t you feel great if you need a rain, but at least the hurricane is headed east.  The only thing for certain about forecasts anymore is that they’ll change.

Fig. 1.  NOAA 7-day Precipitation Forecast.

2021 Rice College is Aug. 12

The 2021 Rice College will be held Aug. 12, 2021 from 9 a.m. to 4 p.m. at the University of Arkansas System Division of Agriculture's Pine Tree Research Station near Colt.  The station address is 7337 Hwy. 306 West, Colt, AR 72326.

Crop consultants, industry personnel, and producers will see current research on many of the production challenges Arkansas rice producers are experiencing today.  Attendees will participate in field presentations from UA Division of Agriculture personnel and have the opportunity to take part in hands-on (boots on!) demonstrations.  CEUs will be available and lunch will be provided.

Cost of attendance is $100 and you must register by Aug. 6 at the following link:  https://bit.ly/2021RiceCollegeRegistration

Link to 2021 Rice College Flyer

Program Highlights:

Tommy Butts

Bolt/STS/non-STS soybean tolerance to ALS herbicides

Row spacing and weed control

Importance of herbicide plant-back restrictions

Jarrod Hardke

Identifying and correcting nutrient deficiences

Jason Norsworthy

Use of Rogue in rice

Loyant coated on urea

Review of seed treatment protection against drift

Rice response to dicamba

Yeshi Wamishe

Identification, scouting, and management of major rice diseases

Nick Bateman and Gus Lorenz

Insect sampling and ID

Management decisions

Seed treatments and foliar sprays

Donna Frizzell

Cultivar selection and management considerations

Deficiencies, Disorders, or High Yield Disease

Jarrod Hardke and Trent Roberts

As we hit the midseason stride with rice, there is a great deal of discoloration showing up that is giving growers and consultants fits in their attempts to push the crop and maximize yield potential.  There are a wide range of issues responsible for the variety of discoloration observed, some of which we should be concerned about and others we should not.

The first issue to note that isn’t really an issue, is one that has been referred to as “high yield disease” (Fig. 2).  This leaf tip effect is often noted on the 2^nd or 3^rd leaf from the top of the plant during reproductive growth (boot stages).  The newest young growth will not have the leaf tip ‘burn’ and neither will lower leaves.  This placement on the plant is one of the keys to distinguishing this particular leaf tip discoloration.  The simple way to define it is plants growing rapidly under high yield potential conditions are likely exhibiting a nutrient imbalance at the tips as they draw mobile nutrients from leaves to amplify their growth.  It could be argued this is exaggerated by the wet conditions this year creating a more shallow-rooted crop, further necessitating the rice to draw more from leaves as it pulls from the roots at the same time.

Fig. 2.  “High yield disease” in rice.

It is always wise, anytime we see any disorder, to look over the entire plant to best determine what’s going on.  In some cases where similar leaf effects have been observed but occur more frequently among all leaves on the plant, is a nutrient draw related to hydrogen sulfide toxicity (Fig. 3).  A quick look at the roots can clearly show if there is a significant amount of blackening related to hydrogen sulfide toxicity.  Hydrogen sulfide is toxic to cells and when present in the soil can lead to root cell death and the blackening that occurs.  The reaction that generates hydrogen sulfide gas occurs in anaerobic soils and when it kills the roots prevents them from delivering needed nutrients to the plant.  When this issue occurs during reproductive growth stages, it is much more difficult to safely and effectively overcome.  To truly eliminate the problem, draining of the soil is required to return oxygen or aerate the soil and reverse the reaction.  However, in reproductive stages there is a risk of a severe drain reducing yields, so instead the attempt is to reduce the flood to a muddy / firm state to get some oxygen to the roots and then reflood.  This often allows us to outrun the issue and maintain yields, but it is still very difficult during the hot and dry period of summer.

Fig. 3.  Hydrogen sulfide toxicity.

Finally, we do have instances of true potassium (K) deficiency out there (Fig. 4 & 5).  Typically, K deficiency appearing on leaves and leaf tips will take on a yellow/red burnt appearance and as the deficiency increases, the ‘burn’ will progress down the leaf margins.  Typically, the new leaves will not show this, but generally all lower leaves will display this.  For cultivars that are susceptible to brown spot, the brown spot disease can be a pronounced indicator of K deficiency and further modify the appearance of the deficiency.  Check deep water areas such as levee ditches to help confirm, as these areas will have more pronounced K deficiency.  Potassium deficiency can be corrected up the late boot stage, so we prefer send in Y-leaf (uppermost fully expanded leaf with a collar) samples to confirm the K deficiency prior to making a corrective application of K.  If making an application, 100 lb potash/acre (60 lb K2O/acre) should be the rate used, preferably with water stable in the field as potash is very water soluble and will move with moving water.

Fig. 4.  Potassium deficiency of rice.

Fig. 5.  Collection of potassium deficient rice leaves.

Getting Geared Up for Rice Stink Bugs

Nick Bateman, Gus Lorenz, and Ben Thrash

We have been observing large numbers of rice stink bugs (RSB) in native grasses along ditch banks and turn rows over the past several weeks.  I know, I know, we say this every year.  We saw similar populations this time last year and we sprayed very little until mid-August for RSB.  We just wanted everyone to be aware that there is potential for some of this early planted rice that will be heading in the next two weeks to be infested with some high populations of RSB.

We have been conducting assays on RSB for the past couple of years to test for resistance to lambda-cyhalothrin (Warrior II, Lambda-Cy, etc.).  Our assays so far this year have shown between 90 and 100% control with a 1X rate of lambda.  This has been the case for the past two years, until we get into late August and September.  We have seen some slippage during that time.  We are recommending to start out with lambda and to scout those fields within 3-4 days after application.  If nymphs are found shortly after an application is made, then that is a sign of a failure, and it’s time to swap to Tenchu, which is the only non-pyrethroid option for RSB control.  If only adults are found, it is more likely that a new flush of RSB have moved into the field.  Just as a reminder our thresholds is 5 RSB (nymphs plus adults) per 10 sweeps during the first two weeks of heading, and 10 RSB per 10 sweeps during the second two weeks of heading.

The last thing we want to cover is adding lambda in with a fungicide application.  You know we are big proponents of IPM and only spraying when we reach a threshold for an insect pest.  We have tried spraying lambda prior to heading, and our data doesn’t support doing this (Fig. 6).  We hear all the time that it’s only a dollar, and I don’t want to ask the grower to turn around and spray a week later for RSB.  Rice stink bugs are seed feeders, and rice has to be blooming with some kernels moving into milk to really be a host for them.  This is why we don’t recommend scouting for RSB until we are 75% headed.  When we make applications of lambda prior to this point we consistently see higher populations of RSB than if we wait until at least 75% heading.  We also feel like this could be part of the problem with the failures we have seen late in the season.

**NOTE:  If you are spraying a fungicide at the proper timing for smut prevention then you are well in advance of having heading rice where RSB pressure would be present to justify an insecticide application.  If you delay the fungicide application until right at heading when you might have more RSB entering the field to justify an insecticide application, then you are too late for the fungicide to have much effect.  There is NOT a situation where spraying a late fungicide and an insecticide together lines up for management of both – you will be too early or too late on one of the products going out.**

Hopefully this year will be like last, and RSB will be a nonissue on a bulk of our acres.  Let us know if you have any questions or need anything.  Also please contact us if you see a failure with lambda so we can make a collection to conduct resistance assays.

Fig. 6.  Application timings for rice stink bug (RSB) control with lambda.

Rice Market Update

Scott Stiles

USDA released its’ much-anticipated June Acreage report this week.  The most surprising aspect of the report was the lack of change from the March intentions.  Likely the report left traders with more questions than answers.  In truth, the acreage picture may not begin to clear until August when we get a first look at FSA certified acreage.

The table below provides a comparison of final 2020 long-grain acres and the NASS Acreage results released this week.  Per the June 30^th report, long-grain planted acreage is expected to decrease 11 percent or 255,000 acres from last year.  Arkansas’ acreage is down 15 percent or 205,000 acres from last year.

For Arkansas, All rice planted area for 2021 is estimated at 1.24 million acres, down 220,000 acres from a year ago and down 10,000 acres from March planting intentions.  Breakout (shown in the NASS figure below) is 1.12 million acres for long grain, 120,000 acres for medium grain, and 1,000 acres for short grain.

“All that work for a thousand acres?”  That may be how they feel at NASS after collecting rice data over the past month.  Historically speaking, this year’s March to June acreage adjustment was the smallest in recent memory.  Going back to 2009, we focused on long-grain acres in the odd numbered years.  Those were years in which rice acreage declined from the previous year.  In every odd numbered year since 2009, the June Acreage total for long-grain was less than the March intentions.  Changes in acreage from March to June have ranged from -25,000 to -300,000, with an average change of -164,000 acres.  Given that, the rice market was caught off guard Wednesday by the meager 1,000 acre net change.  The table below provides a state-by-state breakdown of long-grain March to June acreage changes.

As a reminder, the results of the June Acreage survey will be used in the production estimates for the upcoming July 12^th WASDE (i.e. supply/demand report) and NASS Crop Production.  How will this affect the 2021 balance sheet for long-grain?  At first glance, probably not very much.  The June Acreage report did include a projection for long-grain harvested acres of 2.041 million.  That implies a planted/harvested acreage difference of 1.7% -- the 10-year average.  To calculate production, the key variable we don’t know is yield.  We can estimate that USDA has been using a national average yield for long-grain of 7,479 pounds (166.2 bu./ac.).  If that continues to be the case, then the July production estimate would be 152.6 million cwt.; slightly above the June estimate of 152.3 million.  Again, the key question here is yield.  In the July WASDE, yield estimates are unlikely to change from previous months.  In August we may begin to see some adjustment in yields.

Chicago rice futures have made a nice recovery off the mid-June lows.  The September contract has retraced a full 50% of the slide from the May high at $14.21 to the recent low at $12.50.  With futures now trading in the $13.45 to $13.50 area, new crop rice bids at driers are in the $5.82 to $5.89 range for fall delivery.  Mill offers are at $5.96 per bushel.

In the chart below it’s hard to ignore the bullish flag that’s developed, which may be pointing to a retest of the May highs.  But before getting too excited, keep in mind Wednesday’s Acreage report was a disappointment with many in the trade expecting a lower acreage number and thus some reduction in crop size.  This may keep the rice market in a sideways range for a while longer. For certain though, it seems likely the market will simply shrug off the June Acreage and wait for more information.  For example, the full impact on acres and yield from recent flooding in the state are still an unknown.  More clues about failed acres and prevented planting in all rice states will emerge in August with FSA’s certified acreage reporting.  Until then, trading will focus on weather, crop conditions and export demand.  Have a great Fourth of July!  CBOT markets will be closed Sunday night and Monday’s day session.  Trading resumes Monday night.

CBOT Rough Rice Sep '21 (ZRU21)

Fungicide Timings for Selected Rice Diseases

Yeshi Wamishe

Blast:  For neck and panicle blast, two applications may be required for maximum suppression with the first at late boot to 10% head out and the second at 50-75% head out.  (Head out refers to what proportion of individual heads are out of their boot in about 50% of tillers).  If the necks of the main and secondary tillers are out of the boots, fungicide application is too late. Increase flood depth for early season leaf blast. In cases of leaf burn due to leaf blast, treat hot spots.

Sheath blight:  Boot application and later at heading may be required if a cultivar is S or VS and weather favors disease. If earlier application is done due to severe sheath blight, PD to boot application may be needed depending on how fast the disease progresses.  However, more than one application for sheath blight alone is not profitable. It may be wise to pair timing with fungicides to suppress other rice diseases.

Kernel and False smut: Timing is narrow and critical. > 6 Oz/Acre rate of Propiconazole equivalent is critical to maximize protection/suppression. Difenoconazole containing fungicides such as Amistar Top may also be used alternative to Propiconazole.   

Hydrogen Sulfide (H₂S) toxicity and Straighthead: follow the "drain and dry” strategies.

Bacterial Panicle Blight (BPB): Nothing to be done and hard to predict its presence. Planting seeds from BPB harvest is the best approach to manage this disease.

PHI= Pre-Harvest Index.

Scout for Sheath Blight and Relieve its Harm

Yeshi Wamishe

Scout before deciding on fungicide application for sheath blight and determine the threshold. It is not profitable for Arkansas rice producers to apply fungicides for more than one time to suppress sheath blight alone. If the disease progress is slowed by dry weather conditions and the upper three leaves are not threatened, it is wise to delay fungicide application further to boot stages. Sometimes fungicide application timing for sheath blight may be paired with protective fungicide for the smuts which are from early boot to mid-boot.  In such instances, fungicides may be combined or a pre-mix may be used to address more than one disease. Such an approach should help reduce the cost of application. Remember the recommended timings for a fungicide application to manage sheath blight ranges from panicle differentiation (PD) to boot split.  If the disease gets to the threshold level early in the crop stages and weather is favorable, delaying fungicide application is not an option in the interest of keeping the frequency of application to one.

The sheath blight fungus penetrates the sheath of rice plants at the water-line (Fig. 7) in flooded rice.  Sheath blight in severe situations can cause significant yield loss in susceptible varieties and also weakens rice stems leading to lodging.  In addition to the sheath, the fungus attacks rice’s leaf blades eventually drying them (Fig. 8). Under favorable conditions, the disease progresses vertically following the height of the crop reaching the head and sideways to neighboring plants through tissue contacts (Fig. 9). Sheath blight disease is favored by warm temperatures and high humidity. The disease usually starts from a compact soil-borne fungal mass called sclerotium (Fig. 10) often formed later after lesion formation and nutrients depleted. 

The Main Message: Start scouting from the green ring with greater attention between 7-14 days after jointing and continue until after heading (50% heading). For susceptible cultivars with an “S” or “VS” ratings, the recommended threshold is at 35% positive stops. For moderately susceptible cultivars rated “MS”, the threshold is at 50% positive stops. Positive stop counts assume scouting in a zig-zag pattern (Fig. 11) over a bulk of a rice field not including field edges or bottoms.  Refer to MP192 pages 130 to 133 for more information. 

Note:

1. Automatic application of fungicides is not advisable due to the potential development of fungicide resistance.
2. Sheath blight can start from soil line in furrow irrigated susceptible rice.
3. Weather conditions that particularly favor the vertical progress of the disease are more damaging to rice than the micro-environment that often favors plant to plant disease transfer in lower canopy.

Fig. 7.  The sheath blight fungus penetrates the sheath of rice plants at water-line.

Fig. 8.  The sheath blight fungus attacks the leaves ultimately drying them. 

Fig. 9.  Vertical and horizontal rice sheath blight disease progress. 

 Fig. 10.  Compact fungal masses called sclerotia are formed for lasting survival in soil.

Fig. 11.  Sheath blight scouting requires a zigzag pattern monitoring technique away from field edges or bottoms to make fungicide application decision.

Row Crops Radio Podcasts

Check out these podcast episodes by following the link or by listening to them on Arkansas Row Crops Radio wherever you listen to podcasts.

Lorenz, Bateman, Thrash sound the alert on stink bugs, fall armyworms, and plant bugs (7/1/21)

Rice & Advice, Ep. 04:  Rice Leaf Discoloration, Midseason N, & Boot N (7/2/21)

DD50 Rice Management Program is Live

The DD50 Rice Management Program is live and ready for fields to be enrolled for the 2021 season.  All log-in and producer information has been retained from the 2020 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.