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Arkansas Rice Update 4-25-13
Author: Jarrod Hardke, Rice Extension Agronomist

April 25, 2013                               No. 2013-5

Dr. Jarrod Hardke, Dr. Yeshi Wamishe, and Dr. Paul Counce

Planting Forecast

Actual progress was actually being made.  It wasn’t necessarily fast but it definitely seemed furious.  The early part of the week was certainly prime time.  Wednesday’s rainfall slowed some more than others.  A few people were working ground yesterday afternoon but I don’t know if anyone was really trying to force any seed in the ground.  Today’s beautiful weather may help us make a little more progress before rain arrives again.  Right now that forecast is calling for quitting time to be Friday at 5 p.m.  The forecast is for rain all night Friday into Saturday morning.  It’s going to get worse before it gets better.  They’re already calling for rain chances beginning next Tuesday and extending throughout the week.  Water-seeded rice is beginning to look better and better – “inevitable” may be more accurate.

Picture 1.  Fields were busy earlier in the week – multi-tasking has become a necessity.

Fertilizer Incorporation

Picture 2.  A rare sighting:  emerged rice.

Rice Field Emerging

Don’t abandon all hope just yet though.  Early May is still a fine time to be planting rice.  We’ve done it for years – just perhaps not so much in recent years.  We’ll get it in like we always do and have a good year once we get rolling.  In my mind, and based on the planting date data mentioned last week, if we can get most of it in by mid-May then we should be just fine.  It’s not that we can’t produce a good rice yield when we plant a little later than that, it’s just that a lot more variables enter the equation (as mentioned last week).

Knowing the numbers doesn’t change the fact that it keeps raining, but in case you’re curious I’ve put together some rainfall information.  See Table 1 for a summary of where we stand on rainfall compared to previous years.  This data was obtained from NOAA (not the guy with the boat, but instead the National Oceanic and Atmospheric Administration).  If it keeps raining, we’re going to need Noah.

Table 1.  Monthly Total Rainfall, 2009-2013 (Des Arc, AR).


20-yr avg.


































† 1993-2012            * Total to date

Planting Date and DD50 Units – What Are They Trying to Tell Us?

Worried that you would be a lot farther along this year if you’d been able to plant earlier?  Don’t be – it wouldn’t have made the difference that it did in 2012.

You can see in Table 2 that from March 15-31, we have accumulated only 24% of the DD50 units in 2013 that we did in 2012.  From March 15-April 21, we’ve only accumulated 48% of the units we did over the same period last year.

Certainly it feels like the year is getting away from us – we’ve been spoiled with getting the crop in early in recent years.  Don’t get ahead of yourself though, there’s still plenty of time to get the crop in for a good yield.  Plant under the right conditions and avoid the likelihood of a replant that will multiply your costs and further delay the crop.  Remember the old coaching adage:  “Do it right, do it light; do it wrong, do it long.”

Table 2.  DD50 Units, 2012 vs. 2013






Mar. 15-31



Mar. 15-Apr. 21



Apr. 1-21




RICESEED Seeding Rates

Please take advantage of the RICESEED program for determining your proper seeding rate under increasingly variable conditions.  The program provides an easy way to calculate your best seeding rate according to University recommendations.  Reach all RICESEED information here:

For a more straightforward look at calculating your own seeding rate, please see the attached RICESEED Update for 2013.  This provides minimum, optimum, and maximum seeding rates for rice cultivars, as well as factors to consider which may increase your seeding rate based on your individual practices.

Sheath Blight Fungicide Resistance Remains a Concern for Rice Production

In rice production, sheath blight is a very common disease occurring every year in nearly every Arkansas rice field.  The fungus causing sheath blight survives in the soil, crop straw, and several other crops and grasses year in and year out.  The fungus forms structures called “sclerotia” that can lie inactive in the soil until they come in contact with their host plants.  Soybean is the common rotation crop to rice and is one of their favorite hosts.

Picture 3.  Sheath blight in dense canopy.

Sheath Blight - Dark in Dense Canopy

For many years now, strobilurin fungicides have been used to manage sheath blight disease of rice.  Several hundred thousand acres of rice are treated with fungicides for sheath blight each year in Arkansas.  Sometimes the fungicides are applied without actually seeing the disease.  Sheath blight primarily affects yield and milling quality when it reaches the top two leaves prior to 50 percent heading.  In years like 2012 where it was “hot and dry”, conditions were unfavorable for sheath blight development.  Therefore, several rice fields did not need fungicides.  The tall long-grain rice planted early outgrew the disease.  However, the rain in early July gave a little kick to the fungus and fields of semi-dwarf long-grain rice needed fungicide applications.

As every season is different, planting rice in 2013 has been delayed by the wet and cold weather.  Cold or hot or wet or dry, the sheath blight fungus sclerotia are waiting for their favorite host in soil.  Planting more tolerant varieties is always advisable.  Higher seeding rate to compensate for stand loss and possibly higher nitrogen fertilizer to push the late-planted crop to grow faster could cause severe sheath blight incidence.  Anticipating a severe sheath blight season on susceptible varieties, we would like to remind you that fungicide resistance still remains a concern.  Therefore you need to be vigilant as to how you use the strobilurin fungicides to manage sheath blight.  You should note that current fungicides are most effective under low or moderate disease pressure.  Preventative and routine fungicide applications are more likely to result in the development of resistance than applications based on scouting.

Therefore, we encourage you to scout first and then spray only if needed.  You may not need to spray all acreage “just because”.  Hybrid rice and medium grains are less likely to benefit from fungicide applications.  But if you pushed high nitrogen fertilizer as in the case of CL XL745 in some fields in past years, the story will be different.

Remember the recommendations – “Fungicides for sheath blight should be applied if your effective scouting indicates more than 35% positive stops in susceptible varieties and more than 50% positive stops in moderately susceptible varieties.”

If you ever observe resistant sheath blight, it would be important to remember that the sheath blight fungus can be moved from field to field in soil and water and by equipment.

Please refer to the MP154 – Arkansas Plant Disease Control Products Guide – 2013:

Rice Seedling Diseases:

Rice Fungicides:

You can also contact your county agents for the rate and timing of applications.

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

This information will also be posted to the Arkansas Row Crops where additional information from Extension specialists can be found.  Please visit the blog at


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

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

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