Dr. Jarrod Hardke, Dr. Bob Scott, & Dr. Yeshi Wamishe
August 5, 2016 No. 2016-21 www.uaex.edu/rice
Draining of fields has begun to increase dramatically throughout the state. That can only mean one thing – harvest will follow soon behind. The first commercial production fields have been / are being harvested now. A few others have cut test samples but unfortunately with last week’s rains and the continued high humidity, moisture levels don’t seem to be falling out very fast for many, running 24-26%.
The current forecast suggests that the extreme heat conditions are set to break in the next week. As we complete grain fill a drop in overnight temperatures will be key in maintaining a good quality crop. A drop in humidity with the heat will also be key drying grain down to desired harvest moisture levels.
Keep in mind that no matter how good the standability may be for a given cultivar it can still lodge. Even Roy J can go down under high nitrogen fertilization and strong wind conditions (Fig. 1).
Fig. 1. Severe lodging of green rice.
To get harvest underway, many will likely lean toward to the use of harvest aids. Sodium chlorate can be used to reduce foliage and grain moisture to move fields closer to desired moisture levels for harvest.
However, sodium chlorate should only be applied once grain moisture is below 25%. DO NOT apply if grain moisture is below 18%. In just a few days after application, grain moisture levels can fall up to 5%, so be prepared to harvest no more than 4-7 days after application. DO NOT apply a harvest aid immediately prior to suspected rainy weather that will delay immediate and timely harvest.
Speaking of harvest aids…
Glyphosate in Rice – Just Say No
It seems there are some questions or ideas out there about using glyphosate as a harvest aid in rice. First of all, that is an off-label application. DO NOT apply glyphosate to rice.
Additional reasons not to do this are related to the effect of glyphosate on rice. It should be well known by now the effects of glyphosate on developing rice plants. A rice plant that is not completely developed will be stopped in its tracks. This means if kernels remain to be filled, that stops. Applications would of course be made by air – a recipe for drift onto nearby susceptible rice.
Outrunning Disease Problems
The majority of fields in the state have outrun disease issues for the season. This is one bright spot to the hot, dry conditions. However, many still have questions about the current state of disease problems.
If you have reached 50% heading without sheath blight threatening upper canopy leaves then you have successfully outrun the problem. No yield response will be gained by a fungicide application once we reach this point.
To answer some of the questions out there, yes you might consider a fungicide application around this time. While not specifically recommended, on cultivars with greater lodging potential, the application of a low rate of a fungicide may help to maintain stalk integrity and minimize lodging resulting from sheath blight weakening stalks. Please note that this a grower’s risk treatment – there is not guarantee that there will be any benefit to the treatment.
The low chance of a return should be reason enough not to make the application. One other concern is the pre-harvest interval (PHI) of 28 days for products such as Quadris – this means you cannot harvest within 28 days of the application.
Many fields have outrun or passed the timing for a blast prevention application. While disease pressure has been light this year it is not OK to completely skip a blast application. You don’t need leaf blast to get panicle or neck blast; and vice versa. Once panicle necks are out of the boot it’s too late for fungicide applications.
Fig. 2. Sheath blight blowing through the canopy in heading rice.
Fig. 3. Panicle and neck blast on a susceptible cultivar with no fungicide application.
Wednesday, Aug. 10th
Grand Prairie Center, Stuttgart, AR
Field tours leaving the Grand Prairie Center at 8:15, 8:45, and 9:15 a.m. Program:
- Xueyan Sha and Ehsan Shakiba, Rice Breeding Updates
- Jason Norsworthy and Tom Barber, Rice and Soybean Weed Resistance Management
- Chris Henry and Mike Hamilton, Irrigation Water Management
For full details please visit http://uaex.edu/rice-expo/.
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 firstname.lastname@example.org.
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.edu/rice.
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.