Rice Farming

 - Specialists Speaking -


Managing first crop for a ratoon crop

Dr. John Saichuk

The past few years I have addressed fungicide applications, stinkbug control and draining in the final Specialists Speaking article of the year. This year, I am thinking about next year because problems we have encountered in verification fields where operations, or the lack thereof, last fall affected this crop. I am also thinking about management of the first crop with the ratoon crop in mind.

If a ratoon crop is intended, it’s easier to justify some decisions in the first crop. For example, an extra herbicide application to reduce weeds not only in the first crop but the second as well allows the cost to be spread over time and hopefully higher total yield per acre. Using fungicides in the first crop is also easier to justify when a second crop is planned because healthy stubble in the first crop can make a difference in getting off to a good start in the second. The same reasoning might apply to fertilization. The high cost of fertilizer might tempt some to cut back or omit a phosphorus or potassium application. If a second crop is planned, again the benefit realized from higher yield potential in the second crop helps to spread out costs. More fertilizer, fungicides and better weed control will not guarantee a good ratoon crop, but it sure can’t hurt.

We continue to investigate the benefits of stubble management following first crop harvest. Results from the Rice Research Station in Crowley are still mixed in terms of yield benefit. Everyone agrees mowing or rolling of stubble will delay second crop maturity by about two weeks and will produce a more uniform crop.

Sometimes that two-week delay can make a difference. In the few commercial fields I have followed where the stubble was mowed following first crop harvest, the second crop sample was more uniform in appearance. If better milling follows, that could be important, too. We hope to have more definitive answers soon. Until then, I do not recommend for or against the practice.

After 10 years of verification field work in all parts of the state and on various soil types, I have learned to really like the yield potential of clay soils. I have also learned to appreciate the challenges these soils present. There is not a big enough tractor or plow to work clay soils when they are not ready to be worked. Fight them, and they will kill you; work with them, and they will produce.

One of the ways to pick a fight with clay soils is to harvest when they are too wet. I know sometimes there is no choice. This is why the LSU AgCenter’s recommendation to drain for harvest is about a week earlier on clay soils than on silt loam soils. We will continue to evaluate the high moisture meter we started testing a couple of years ago to help make that decision more precise. For the time being, we still recommend draining (on clay soils) when about half of the panicle is straw-colored. On silt loam soils, we recommend waiting until two-thirds to three-fourths of the panicle is straw-colored.

We have watched the development of reduced-tillage systems for the past 10 years or so. They seem to fit especially well on clay soils. Preparing a seedbed in the fall is one of the best ways to manage clay soils. This sets the field up for planting the next spring – even if it is a wet spring – and gives the farmer more options on planting methods. Our experience with the verification program has shown that as soon as the crop is harvested, field preparation should begin. It is often hard to think about next year before you have finished this year, but the best farmers I have worked with always do.

Scout for stinkbugs

Dr. Nathan Buehring

This year’s rice crop will be the most expensive one we have grown. Luckily, current rice prices are good enough to pay for this expensive crop. As we move through this season, the bills will keep piling up and towards the end of the season some might be hesitant in spending more money. However, I would encourage producers to keep monitoring and investing in their crop if necessary. One late-season pest that can be overlooked is rice stinkbugs. The last couple of seasons, rice stinkbugs have been relatively light. Considerations of an insecticide application still need to be made if rice stinkbugs are at or above threshold levels.

Once the rice begins to head, scouting for stinkbugs needs to begin. I would begin scouting with a sweep net around the edges of the field and move towards the middle of field. Sometimes stinkbugs can be found just around the edges of the field. If this is the case, I would recommend applying an insecticide around the borders. This will control the present population and keep them from building up to be a bigger problem. Also, fields that have escaped grass in them are more prone to have rice stinkbugs. Therefore, keep a watchful eye on those fields.

Stinkbugs are more detrimental towards yield during the first two weeks of heading because they are affecting kernel development. The current economic threshold for Mississippi is five stinkbugs per 10 sweeps during this time. If stinkbugs are a problem at this time, I lean toward the use of a pyrethroid insecticide. This will give you a couple of days of residual activity for longer protection.

As we move into the third and fourth week of heading, our economic threshold increases to 10 stinkbugs per 10 sweeps. During this time, stinkbugs are feeding more on mature kernels; therefore, a reduction in grain quality (pecky rice) becomes more of an issue.

The following pyrethroid insecticides are currently labeled and recommended for rice stinkbug control: Karate Z (1 gallon/50 to 80 acres), Mustang Max (1 gallon/32 to 48 acres), and Prolex (1 gallon/62 to 100 acres). The old standby of methyl parathion 1/2 pound/acre or 1 gallon/8 acres can also be used.

One last reminder about stinkbugs is to scout early in the morning or late in the evening. As temperatures rise through the day, stinkbugs will generally move down into the canopy. If you are scouting during the hottest part of the day, take that into account when determining when to spray or not to spray.

Control late-season insect pests

DR. M.O. “Mo” WAY
Rice Extension Entomologist

In Texas, spring weather has been unseasonably cool, so our rice crop development is very erratic. Also, due to the increase in the price of rice (and I know input costs also have risen dramatically), more acreage is being planted late this year. I have observed quite a few fields of late-planted rice, which typically translates to more pest problems, such as fall armyworm, stem borers and rice stinkbugs. Recently, I have found yellow sugarcane aphid, thrips, South American rice miner and black bugs attacking preflood rice. I think the cool dry weather is somewhat responsible for these problems.

Usually, a flush or flood will take care of these early season pest problems, but in some instances, an insecticide application is required. Many of our Texas rice farmers tankmix a pyrethroid with preflood herbicides to control rice water weevil in areas where weevils are typically bad. This is a very effective practice. Our data show the closer a pyrethroid is applied to the flood, the better the control. However, sometimes our farmers have to apply a pyrethroid soon after rice emergence to control early season pests, such as fall armyworm, aphids, chinch bugs, etc. Again, our data indicate these early applications give considerable control of rice water weevil.

We just completed a multi-year planting date study evaluating the benefit of controlling rice water weevil. We found the optimum planting window – late March to mid-April in Texas – is associated with the most severe damage and the greatest economic benefit of controlling the weevils. We found, across all planting dates and insecticide control options, the benefit of controlling rice water weevil is about 600lb/acre on the main crop and 200lb/acre on the ratoon crop. Controlling rice water weevil on the main crop produces a healthier ratoon crop, which means a higher yielding ratoon crop.

Another late season pest is the rice stinkbug. My ex-graduate student, Dr. Luis Espino ( currently a rice farm advisor in California), developed new economic thresholds for this pest. These thresholds are published in the 2008 Texas Rice Production Guidelines, which you can access at http://beaumont.tamu.edu. The new thresholds are much higher than the old ones, which is welcome news. Also, Texas submitted a Section 18 for Tenchu 20SG which is a Mitsui Chemical/Landis International rice stinkbug insecticide. At the time of writing this article, the submission package was in review at the Texas Department of Agriculture. I am hopeful this product will be available to our Texas rice producers by the start of the rice stinkbug season. I will keep you posted.

Well, we are already in the middle of our rice growing season in Texas; seems like we just planted a few days ago. The older I get, the faster the days, weeks, months and years fly by. Life comes at you fast!!! But, I am sensing a more positive, although cautious, outlook from our farmers this year. This hope is contagious, so I am feeling better about our industry. Our farmers deserve a fair price for the nutritious and safe staple they produce at great risk and hard work expended.

We are heading toward the finish line, so don’t let up; keep scouting your fields and taking advantage of available technology. You can be a Triple Crown Winner this year. I’m pulling for you (and for Big Brown)!!!

Harvest moisture

Biological & Agricultural Engineering

Two years of experiments show that California’s newest medium grain varieties, M205 and M206, can be harvested at low moisture contents and maintain high headrice yields. Tests at the Rice Experiment Station near Biggs, Calif., and trials near Colusa and Natomas, Calif., demonstrated that M206 maintains high headrice quality over a wide range of harvest moisture contents, compared to the older M202 variety. In both seasons, the RES tests showed M206 can be harvested at moisture contents as low as 17 percent with little or no loss in headrice yield.

In the Natomas and Colusa trials, M206 showed some loss in headrice at harvest moistures near 17 percent, but it had six to eight points higher headrice yield than the old standard M202 variety.

The testing with M205 showed similar results to M206, although it tended to have slightly lower headrice quality when harvested at low moisture contents. It also performed much better than M202.

Growers traditionally harvest medium grain rice at average moisture contents of 19 to 21 percent. The ability to harvest at 17 percent gives them expanded flexibility in harvest timing. Lower harvest moisture also means fewer passes through the column dryer and significant savings in energy and drying costs. Growers should experiment with lower harvest moisture contents if they are raising M205 and M206 to see if they can harvest the benefits of these two new medium grain varieties.