Arkansas Rice Update 8-1-25

by Jarrod Hardke, Rice Extension Agronomist - July 31, 2025

Arkansas Rice Update 2025-19

August 1, 2025

Jarrod Hardke & Nick Bateman

“Just find a place to make your stand, and take it easy.”

August and Everything After

July finishes with a bang for northeast Arkansas as the cold front yesterday dropped over 2 inches of rain in places.  Didn’t have that on the bingo card.  That’s a big winning combo of irrigation savings and 5+ days of cooler temperatures – a break we were desperately in need of.  The question is, did the break in temps come too late?  See more on temps in the update.

I continue to throw around that word “uneven” with regularity.  Early season rains affecting fertility followed by the late season run of high temperature stress seem to be the big contributing factors to this unevenness.  Some odd rice growth is showing up occasionally that can also be attributed to these conditions, from rice putting on late tillers low in the canopy to producing longer, strung out panicles.  I wouldn’t go so far as to call these common by any stretch, but it adds to the oddities of the year.

Read on below for more information on drain timing, 20% moisture predictions, temperatures, and rice stink bug termination.

Let us know if we can help.

Fig. 1.  NOAA 7-day precipitation forecast.

Field Days

Aug. 7 – Rice Research and Extension Center Rice Field Day

2900 Hwy. 130. E., Stuttgart – Registration starts at 7:00 a.m., tours at 7:30 a.m.

Aug. 14 – Pine Tree Research Station Field Day

7337 Hwy. 306 W., Colt – Details TBA

Rice Weed Science Workshops

https://www.uaex.uada.edu/media-resources/news/2025/july/07-24-2025-ark-rice-weed-workshops.aspx

Aug. 5 – Colt – Pine Tree Research Station, 7337 Hwy. 306 W.

Aug. 6 – Keiser – Northeast Research and Extension Center, 1241 W. County Road 780

Aug. 8 – Stuttgart – Rice Research and Extension Center, 2900 Hwy. 130 E.

Ricing Around

Jarrod Hardke

Drain Timing

Drain like it’s never going to rain again.  I say that every year, but with this year and this forecast it looks really true.  When we drain too early in rice development we can risk yield and quality loss, and when we drain “on time” for rice development but too far ahead of the combine we can risk quality loss and lodging.

Recommended drain timing continues to be 25 days after 50% heading for long-grains and 30 days for medium grains.  Our newer medium grains may need some revising in the future but for now that’s still the recommendation.  The DD50 Rice Management Program builds these recommended dates into the program – but temperature, rainfall, humidity, and sunlight can impact how grains mature so we need to look at the rice around these times and not strictly go by just the number of days.

There was anecdotal evidence last year that not draining too early may have provided some help with milling yields – not that it was a savior, but they seemed to be better than those drained too far in front of the combine.

In Fig. 2 below:

Left, nearly all kernels are straw-colored – safe to drain for all soil types.

Center, 2/3 of kernels are straw-colored – safe to drain on silt loam soils.

Right, 1/3 of kernels are straw-colored – safe to drain on clay soils.

Fig. 2.  Rice panicles at different maturity levels described by kernel percent straw color:  (L) 100%, (C) 67%, and (R) 33%.

Changes to 20% Moisture Prediction

For many years, the prediction of 20% grain moisture in the DD50 Rice Management Program was based on 35 days after 50% heading for long-grains and 40 days after 50% heading for medium-grains.  Plotting data from recent years (2022-2024) this past winter, it appears that a more correct prediction is 40 days after 50% heading for long-grains and 45 days after 50% heading for medium-grains.  Looking back to data from 2014-2016 the results for cultivars and those years more supported the old recommendation.

So – if you notice a little larger gap between drain timing and 20% moisture predictions – that’s why.  Certainly, as we begin harvest we want to monitor this prediction change closely to see if it holds.

While we strive to have the DD50 program be accurate in its predictions, we prefer that it lean early if anything so that we’re ahead of timings rather than behind.  With this change to a more accurate timing, I hope we avoid a recurring situation of cutting a sample that’s too high then waiting too long to try again and we’re actually behind.  That has happened repeatedly in recent years – “tried a sample when it was supposed to be 20% but it was still 23%, came back and it was 17-18%”.  That starts us behind the 8-ball and can lead to later rice harvested at sub-optimal moisture levels.

More on High Temps

Fig. 3 is not one to make you feel all warm and fuzzy right now.  Basically, nighttime temps have been trending along with the likes of 2010 and 2011 to this point.  Remember though that the timing of the accumulation has as much to do with its impact as the nights themselves.  2010 and 2011 speak for themselves.  2015, 2016, and 2022 accumulated a lot of nights early but then tapered off in August not appearing as high in total.  2023 accumulated most of those nights much later so the total was high but late enough to reduce crop impact.  2024 and 2021, our most recent record yield years, were very much middle of the road before some late August nights pushed them just into the upper half of these years.  2018 was on a similar track to ’10, ’11, and ’25, but the night nights essentially flatlined after mid-July and ended up a good year.  Going to Figs. 4 and 5, the accumulations are a little different but the same trends show up.  At Keiser, this year is a little more middle of the road but still on the negative track of ’10, ’11, ’15, and ’16.  For Jonesboro we’re in the heart of the ’10, ’11, ’15, and ’16 trend.

Fig. 3.  Cumulative nights of 74 or greater from June 1 to August 31 from 2010 to 2025 for Stuttgart.  Text box inlaid is ranked order by year of most nights with the corresponding final state average yield.

Fig. 4.  Cumulative nights of 74 or greater from June 1 to August 31 from 2010 to 2025 for Keiser.  Text box inlaid is ranked order by year of most nights with the corresponding final state average yield.

Fig. 5.  Cumulative nights of 74 or greater from June 1 to August 31 from 2010 to 2025 for Jonesboro.  Text box inlaid is ranked order by year of most nights with the corresponding final state average yield.

Following the issues experienced in 2016, I put together a set of figures displaying trends in average daytime and nighttime temperatures for July 16 to August 15.  Below I have provided updated versions of these figures through 2024.  They continue to paint an unwelcome picture of nighttime temperature trends during our July and August grain filling window.

Fig. 6.  Average daytime high and nighttime low for July 16 to August 15, 1976-2024, Wynne.

Fig. 7.  Average daytime high and nighttime low for July 16 to August 15, 1976-2024, Jonesboro.

Fig. 8.  Average daytime high and nighttime low for July 16 to August 15, 1976-2024, Stuttgart.

Rice Stink Bug Termination

Nick Bateman

Some rice is reaching drain timing and with that, the time for insecticide termination for rice stink bug (RSB).  We still have plenty of rice in susceptible stages and a long way to go with this spread out crop, but we want to get ahead of this topic to prevent any unnecessary applications.

While many continue to report low RSB numbers, there are fields out there showing up with plenty to treat.  Almost 10 years ago we had a very late influx of RSB after rice had been drained and realized there really wasn’t an established cut-off / termination timing for when RSB could no longer damage rice.  After several years of work, we have determined that when rice reaches 60% straw-colored kernels on the panicle, the chances of getting peck decrease substantially and we can terminate insecticide applications for RSB (Fig. 9).  **Note that when we say straw-colored we’re referring to kernels no longer being green, don’t get caught up on shades of yellow.**

The data shown in Fig. 9 used caged RSB on individual panicles – where they have no choice but to feed on those kernels or die – the definition of a worst-case feeding scenario.  Peck numbers are higher than we normally see in field settings because of this “forced feeding” approach.  We do want to be pretty clean at 60% straw-color as high populations can still cause some damage at this point.  If several days of rain are in the forecast, we may need to extend that termination timing a little as rains can soften kernels that aren’t fully mature at this point and keep them susceptible to damage.

If an application is needed around the termination timing, there are options to consider.  Populations around threshold (10 RSB per 10 sweeps) then lambda-cyhalothrin may be a cheap option – even with only 50% control of RSB it can be enough to finish things out.  If numbers are higher, say 15 RSB per 10 sweeps or greater, then Tenchu should be considered to bring numbers down well below threshold.

Feel free to reach out to us if there are any questions.

Fig. 9.  Damage (peck) caused by rice stink bug feeding.

DD50 Rice Management Program is Live

The DD50 Rice Management Program is live and ready for fields to be enrolled for the 2025 season.  All log-in and producer information has been retained from the 2024 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.