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Arkansas Rice Update 7-26-13
Author: Jarrod Hardke, Rice Extension Agronomist

July 26, 2013                              No. 2013-18

Dr. Jarrod T. Hardke, Dr. Gus Lorenz, and Dr. Yeshi Wamishe

Crop Progress

Heading is getting into full swing.  By the DD50 numbers we’ve been a little behind where we should be.  I blame this on the cool spell we experienced in mid-May that put the brakes on emerged rice.  After scratching my head a little, I now think that a few days of heat units after the cold spell were spent just getting the crop to the point where it was ready to grow again, which the DD50 can’t account for (it just adds up heat units).  No matter how good the program, nature can find a way to give it fits.

All this cooler weather sure has made work in the field nice.  Until you look at the updated harvest projection in Table 2.  If you compare to the numbers from last week you’ll see that we’re looking at a noticeable shift – to being later.  That is certainly not what we’re looking for right now.

All we can do at this point is keep the faith.  That and repeat my mantra from last week, “NO EARLY COOL SPELL.”  Instead of the first fields reaching 20% moisture the first week of August as I mentioned last week, they’ve now shifted to the third week.  The upside to the weather forecast?  Upper 80s and low to mid-90s keep the nighttime temps down where they shouldn’t impact quality.  If we’re looking at decreased quantity, increased quality will hopefully pick up some of the slack.

Applications for kernel/false smut and stink bugs are getting rolling, along with some applications for sheath blight.  More information on these topics on the following pages.

The Rice Expo is next Friday!

AR Rice Expo Logo

Tables – Percent of rice acres to reach growth stages during listed weeks of 2013 according to current DD50 enrollment.
Table 1. 50% Heading Table 2. 20% Grain   Moisture
50% Heading   Date Percent Harvest Date Percent
50% Headed 55% Aug 3-9 0%
July 26 – Aug   1 25% Aug 10-16 0%
Aug 2-8 12% Aug 17-23 18%
Aug 9-15 5% Aug 24-30 27%
Aug 16-22 2% Aug 31 – Sept 6 29%
Aug 23-29 1% Sept 7-13 16%
Sept 14-20 7%
Sept 21-27 3%
Sept 8 – Oct 4 1%


Out Standing in Your Rice Field

 Rice Stink Bug

“Here a stink bug, there a stink bug, everywhere a stink bug.”  With more and more rice acres heading, here come the rice stink bugs.  Reports of 15-20 stink bugs per 10 sweeps are common.  For those of you keeping score at home, that’s 3-4 times threshold (5 per 10 sweeps) for the first two weeks of heading.  Easy call to treat in these situations.

Continue to be diligent in scouting.  Early morning and late evening are the best times to scout to get accurate numbers.  Only treat when needed based on thresholds.  DO NOT just throw an insecticide in the tank while making a pre-heading fungicide application.  This will only disrupt the beneficial insects in the field and open the door for large stink bug populations just waiting for your field to head out.  If populations remain high you may have to treat twice anyway, waste one and you’ll be looking at three sprays.

Picture 1.  Abandon all hope, ye rice stink bugs who enter here.

2013-18 Picture 1

Disease Notes

A bigger concern this week was sheath blight.  The weather has been and still appears very favorable for the disease.  The fungus is moving fast in thicker canopies.  We typically recommend a fungicide for sheath blight from 5-20 days after midseason (1/2-inch IE), developmentally 2-inch IE to mid-booting.  For more information, including equivalent fungicide rates, go here:

Picture 2.  Sheath blight two weeks after artificial inoculation in the field at RREC.2013-18 Picture 2

In Arkansas it is not economical to spray for sheath blight more than once.  However, you have to continue monitoring and make sure the upper three leaves, including the flag leaf, are healthy at heading.  One question we got this week required a judgment call.  The question was whether or not to treat Roy J at boot split where lesions reached halfway up the plants.  With the rain forecast continuing the next few days, we thought one shot with a lower rate of Quadris would be enough to inhibit further progress of the disease for at least the next two weeks.

Some concerns were also raised on prophylactic (preventative) fungicide treatments for kernel smut on moderately susceptible cultivars.  If the field has a history of kernel smut and has been overly fertilized (N), the chance will be high for quality loss even in cultivars rated MS (moderately susceptible).  However, if the field has a history of kernel smut and the nitrogen rate is adequate (which you can tell from the appearance of the crop) you may opt not to treat for cultivars that are rated MS.

To treat or not to treat Mermentau for smut was another question.  As this variety is new, we do not have kernel smut ratings for it in Arkansas yet.  However, it was rated MS for false smut last year.  From its pedigree, there is a high chance it could rate S or MS for kernel smut.  To treat or not to treat is again a judgment call based on the field history and the preflood nitrogen rate.  See more answers to questions on smuts here:

Aug. 1 – Consultant Training / County Agent In-Service Training

The 2013 University of Arkansas Rice Consultant and In-Service Training will be held Thursday, August 1, 2013 beginning at 8:30 a.m. at the University of Arkansas Rice Research and Extension Center located 7 miles east of Stuttgart on Hwy. 130.

This field-based training session will include talks on Arkansas rice breeding developments, disease updates, rice insect management, rice production and irrigation methods, N-STaR and soil management, and issues in weed control.  Speakers include Dr. Jarrod Hardke, Dr. Gus Lorenz, Dr. Karen Moldenhauer, Dr. Trent Roberts, Dr. Bob Scott, and Dr. Yeshi Wamishe.  CCA credits will be available for crop management (1), integrated pest management (3), nutrient management (1), and soil & water management (1).  For more information please contact Dr. Chuck Wilson ( or Dr. Jarrod Hardke (

Need Help with DD50 Enrollment?  Call or E-mail Me or Your Local County Extension Agent

If you prefer to enter them yourself, please visit

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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