September 12, 2013 No. 2013-25
Dr. Jarrod Hardke, Dr. Gus Lorenz, and Dr. Yeshi Wamishe
Many growers are continuing to make quick work of harvest these days. The majority of yield numbers coming in are 180+ bu/acre with most numbers in the 200+ range. Difficult to be unhappy with those kinds of yields. However, some growers are reporting yields ~15 bu/acre lower than what they achieved last year. Will we finish out the year in the range of last year’s state record average 166 bu/acre? Still too early to tell on that one. Late-planted rice still has a lot to say in that conversation and we’re not to it yet.
Current weather is ideal for harvest with most days having a relatively light dew (except this morning). Saturday’s high of 80 isn’t great for finishing up rice but it will be perfect if you’re at a football game. We should quickly return to the low 90s and upper 80s with drier air helping reduce grain moisture. Make as much progress as you can while the time is right though, rain chances begin to pick up toward the middle and end of next week.
For some reason, there are reports of rice ready for harvest beginning to want to lodge in certain locations (no high winds reported). The exact cause is probably due to a number of factors including possible high nitrogen rates, but it will be important to get the rice out before it lays down too much. Be aware and watch your fields closely.
DD50 numbers indicate that 94% of the crop is ready for harvest (Table 1). Some fields that should’ve reached that point already have not. Mixed reasons why, but strange early-season weather and situations that caused delays in flooding probably had something to do with it.
Table 1. Percent of rice acres to reach 20% grain moisture during listed weeks of 2013 according to current DD50 enrollment.
|Sept 28 – Oct 4||
Long-grain – 25 days after 50% heading.
Medium-grain – 30 days after 50% heading.
Out Standing in Your Rice Field
Rice Stink Bug
Remember, it’s not over until 28 days after 50% heading. If you had fields with areas that took a really long time to get to 50%, those areas will also be susceptible to rice stink bug for longer. Judgment calls will need to be made. Remember, “hard dough, let it go”.
After 50% heading:
Weeks 1 & 2: 5 stink bugs per 10 sweeps.
Weeks 3 & 4: 10 stink bugs per 10 sweeps.
In our visits this week to rice fields, we saw quite a bit of late-season diseases. In our experimental fields in Desha, Arkansas, and Clay Counties where no protective fungicides were applied, false smut has been the prominent disease (Pictures 1, 2). Sheath blight also was to a significant level in the Arkansas and Clay Counties.
Pictures 1, 2. False smut earlier stage (left) and mid-stage (right). Molds on the leaves (right) are sooty molds.
We visited a producer field of CL152 in Randolph County with high levels of neck blast (Pictures 3, 4). The blast was worse near the tree-line. The soil at that location is sandy and therefore more prone to blast because of difficulty maintaining an adequate flood depth. Varieties that are known to be “better” in resistance may turn to “bad” when conditions are more favorable for the pathogen’s survival and reproduction than to the crop.
Pictures 3, 4. Neck rot or neck blast (left) and nearly blank panicles (right). Affected panicles are whiter than tan.
We have not seen much bacterial panicle blight in producer’s fields. However, inoculated seeds planted in late May in experimental fields have started showing the disease, indicating infected seeds planted late still can show the disease.
We saw some molds in drained rice fields ready for harvest. These molds appeared to be encouraged by dew, dead tissues from insect or bird attacks, or some environmental conditions such as cold temps. The discoloration that may be caused by different molds in delayed harvest situations, especially after a rain, may result in quality issues. The quality aspects would be more noticeable when the rice is parboiled. Sooty molds are more conspicuous since the spores are easily seen on the leaves (Picture 5). Sooty molds together with kernel smut could be confused as being heavily infected with kernel smut (Picture 6). However, at least we know something. Either sooty mold or kernel smut or the two together (or including false smut) could serve as an indicator of excess nitrogen fertilization. Some opportunistic late-season microorganisms may also damage the rice grain in storage.
Pictures 5, 6. Matured rice with sooty mold (left) and kernel smut and sooty mold affected rice (right).
A couple of fields have been a bit confusing: Jupiter with aborted kernels was found in Randolph County – thought to be caused by environmental conditions (possibly cold temps) (Picture 7); and CL151 with “big brown spots” that appeared to be leaf-burn (Picture 8) – thought be caused by complex factors (water management, low nutrients, and possibly herbicide drift).
Pictures 7, 8. Jupiter with aborted kernels at panicle tips (left) and CL151 leaf-burn (right).
It is best to wait until rice is below 25% moisture before making a harvest aid application (do not apply below 18% moisture). Expect grain moisture to fall up to 5% in just a few days. Applying sodium chlorate to rice below 25% moisture and harvesting in 4 to 7 days will not result in a reduction in grain yield or milling yield.
Remember that any weather (rain) which could prevent you from harvesting the field within a few days after harvest aid application can lead to serious problems, possibly resulting in reduced milling yields and increased shattering. You’ve worked hard all year; don’t mess up the end game.
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 http://dd50.uaex.edu/dd50Logon.asp.
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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.