Specialists Speaking - May 2008
It’s All About Timing
The USDA estimate for cotton acreage in Missouri is now at 300,000 acres. Field preparation and planting of all crops have been delayed due to the excess rainfall and cool temperatures. There is hope that most of the heavy rainfall is over for a while and the warmer temperatures and the wind will help dry up some of the fields.
There will be additional problems this year with the seep water along the levees. Some areas of these fields will remain wet for a long time. It is possible that several fields will be too late for cotton planting, so soybeans are a better choice. The water standing in some areas of the field will indicate that work needs to be done during the offseason to correct them.
Although early May is shown to be the best time to plant cotton in the Bootheel, later planting dates are better than they previously were. The boll weevil eradication program has allowed the top crop to be harvested, and in most years later-planted cotton will still be a better choice than soybeans.
Field preparation was difficult this year, and there is so much to do. It is best to stay out of wet fields because the problems of getting in too early will remain for the entire season. The early seedling and plant development is so important that producers really need to be patient. Delaying planting will allow better conditions and reward those who wait.
Subsoil moisture is higher from late winter and early spring rains than in the past few years. This should make getting stands of cotton easier and faster and more uniform. Uniform and early stands of cotton make weed control and fertility decisions easier and timelier and may ultimately result in fewer inputs and higher yields.
Many producers are looking at new varieties of cotton with BGII and Roundup Flex technology. Even though this will allow later applications of glyphosate, weeds should be controlled in early stages of growth and residual herbicides applied either at planting or layby or both to prevent weed resistance and allow lower use rates. Residual herbicides will aid in managing late weeds, too.
Some producers went back to conventional tillage this year to reduce weed competition. The heavy rains after deep tillage caused excessive erosion in many fields. With high fuel prices and the loss of nutrient-rich topsoil, it is important that we know that weeds can be managed effectively in conservation tillage systems with residual herbicides and proper crop rotations without resulting in the gullies and soil loss that we saw early this spring.
There is enough data from cotton production states to show that weeds can be controlled as effectively in conservation tillage systems as in conventional tillage systems. Our results show that profits can be from $20 to $70 per acre higher in conservation tillage systems than with conventional tillage.
Conservation tillage is widely accepted around the country with all crops and is a valuable practice for economical cotton production with current costs for labor, fuel and equipment.
May is the traditional month to plant cotton in Georgia. However, there will be more “June-planted” cotton this year due to a significant increase in wheat acres. Regardless if you plant in May or June, it is important to get the crop off to a great start.
Pre-plant fertilizer, land preparation, thrips control and planting depth all play a key role in getting a good stand. For June-planted cotton there is even less room for mistakes.
Planting a short-season variety, going more conservative with nitrogen applications and judicious use of growth regulators are the keys to a successful late-planted crop.
At the time of this writing (April 16), no cotton has been planted in Mississippi. However, by the time you are reading this, cotton planters should be rolling if the weather cooperates. With input costs increasing all the time, we need to focus on increased management of our inputs.
The heavily front loaded cost of planting cotton (seed, seed treatments and technology fees) demands that extra care be exercised with seeding rates and seed placement.
Although it seems logical to reduce seeding rates to some degree to stretch the number of acres planted per bag of seed, reduction in seeding rates places increased emphasis on strict management. Reduction in seeding rates leaves less room for error in terms of seeds that don’t germinate or a reduction in plant population due to weather, disease, insects, etc.
I would encourage everyone to use the seeding charts supplied with a given planter as a guide; however, it is worth the time and effort to check and adjust planter calibration settings based on the actual number of seeds coming out of the planter.
In 2007 about 35 percent of Texas acres were planted to Roundup Ready Flex varieties, and that number will likely increase in 2008. Because of the “flexibility” of spraying on the weed stage of growth rather than crop stage, in many of those fields producers had the tendency to wait longer before spraying in hopes of getting more weeds to emerge.
Consequently, weeds were growing along with the cotton for a longer duration, and at the same time the weeds were getting larger and more difficult to control. And at the end of the season this field just didn’t make as much cotton as anticipated. Could weed competition be the cause? Absolutely!
It is important to recognize that crop loss or yield reductions occur early in the season when you would least expect it. Cotton is a slow starter and is not a strong competitor with weeds. Consequently, cotton fields need to be fairly weed-free for an extended period – up to eight to 10 weeks after planting. Although it may not be visually apparent, early-season competition from weeds can drastically reduce final yield.
Many producers will be wondering if they have glyphosate-resistant weeds with all the talk concerning resistant weeds this winter. Producers should wait until harvest time to try to determine if they truly have resistant pigweed or horseweed, or if they are just escapes.
Producers also should look at fields after glyphosate applications. Look for weeds that do not seem to be affected by glyphosate. Look for weeds that are being controlled by glyphosate. If these controlled weeds and the weeds that do not appear to be controlled are intermingled, there is a good chance you have a resistance problem.
If they are not intermingled,
there is a good chance that the weeds were not treated or missed by
the application. If we don’t look at this situation early, every
escaped weed will be considered to be resistant by next winter.
With the devastating droughts that Alabama cotton producers endured in 2006 and 2007, rainfall during this past winter and early spring has brought hope for the 2008 crop. Cotton acreage is down this year compared to the past few years across the state.
While this may not be the best news for the cotton infrastructure, it will allow many of our producers to rotate to cash crops that will help us to better manage pest complexes. In particular, the nematode complexes have proven to be difficult to manage in a continuous cotton system. We are still waiting to see just how effective the seed treatments for nematode suppression are, especially for the reniform nematode.
Agents and specialists from the Alabama Cooperative Extension System and Auburn University will be conducting numerous on-farm trials this season. This effort is supported in part by producer checkoff funds and private industry.
According to Dr. David Kerns, Extension entomo-logist in the Texas High Plains, early-season thrips control may be the one of the best investments that producers can make in tight economic times. Northern High Plains irrigated cotton producers can expect an average of a 21 percent yield increase when thrips are managed properly, according to tests conducted over the last 20 years. Lower yield increases may be obtained in other areas.
In the High Plains where western flower thrips (WFT) is the predominant species, the best performing preventative treatments have been in-furrow applications of Temik and seed treatments of Cruiser, Avicta and Aeris.
Aeris is a recently-released product from Bayer CropScience and contains the insecticide, Gaucho Grande, as well as a nematicide, thiodicarb. Although the seed treatment Gaucho Grande has not performed well against WFT in university trials in the High Plains, Aeris was effective against WFT in the 2007 tests.
It is believed that the thiodicarb component may be controlling the thrips or enhancing the activity of Gaucho Grande. Avicta is similar to Aeris in that it also contains an insecticide, Cruiser, as well as a nematicide, abamectin. Based on 2007 test results, Temik, Cruiser, Aeris and Avicta all performed similarly for controlling thrips.
A lot of things about growing cotton will make you stop and scratch your head. It is a complex crop that can be unforgiving of poor timing, yet exhibit amazing tolerance to stress. Cotton producers are faced with difficult decisions almost every day of the growing season. One of the most difficult of all is the evaluation of a skippy stand and the decision of whether or not to replant.
The major problem with a replant decision is that no one has yet figured out how to predict the future. Some situations are obvious stand establishment failures, and replanting is the only choice. Most times, however, when the issue comes up, it is a borderline call.
The first two things to determine are 1) the stand count, and 2) how many large skips are there? With even distribution, one plant per row-foot is usually an adequate stand. Cotton is an elastic crop and will fill the gaps. We like to say it compensates, but that is really a misnomer. The branching of the plant and the ability to set outer position bolls will fill in gaps down the row. The presence of numerous large skips of three feet or more will exceed the ability of the plant to fill in these gaps and certainly reduce yield.
A thin stand of cotton will be later maturing than a normal plant population due to a greater percentage of bolls being produced on outer positions. Therefore, the calendar date on which the decision is made must be considered.
This leads us to the most pressing decision when facing a potential replant. It is tempting to say simply that a skippy stand will result in X amount of yield reduction. That is true, but the real question should be what will this skippy stand yield compared with cotton planted tomorrow? The later this decision is made, the less the replant can realistically be expected to yield. Moreover, conditions need to be good for the replant to emerge quickly and achieve a full stand. Dry soil conditions, among other factors, can reduce the likelihood of obtaining a stand the second time.
The old adage of “If there is doubt, its best to leave it” usually holds true. The reduced use of pre-emergence herbicides has helped to make the decision less complicated. However, with the costs often associated with replanting, working with a skippy stand, particularly in a full-season environment is often the right decision. Remember, an ugly, skippy stand at the cotyledon stand is often un-noticeable and all but forgotten at match head square.