Cotton Links

Specialists Speaking - October 2008

Timeliness Is Key To Harvest

Mike Milam

According to the Missouri Crop Progress and Condition Report for the week ending Sept. 7, cotton is 28 percent open, which is two weeks behind last year and a week behind normal. To date, we have had no cotton picked.

One of our concerns is that we have more moisture than we would like to have at this point in the season, and we are expected to get rain and wind from Hurricane Ike. So it looks like regrowth might be a challenge this year.

With the cooler temperatures, producers are urged to use tankmix combinations and follow product label recommendations on adjuvants to allow for good defoliation and regrowth inhibition. The use of thiadiazuron (Dropp, Ginstar and Leafless) is recommended as part of the tankmix. The success of regrowth control is highly dependent on rate, plant condition and weather.

The first year of the Missouri Boll Weevil Eradication Maintenance program has been very successful with 14 weevils caught to date. This compares with 1,049 caught in 2007. This program had returned $5 for every $1 invested. Producers should be very proud of this program.

The irrigated cotton has looked good all season long, and I have seen some very good looking cotton. The USDA yield estimate is 963 pounds per acre for Missouri. However, this was prior to Hurricane Ike so we will wait and see what happens.

David Wright

Hurricanes and tropical storms in late August and September are a reminder of what can happen to crops in the Southeast. A season of good management and hard labor can turn into poor yields and quality overnight.

It is imperative that producers have the capacity to harvest a crop as soon as it is ready to take advantage of the highest quality, yield and longest, warmest days. Defoliants work best with warmer temperatures and longer days. Likewise, if cotton is defoliated and not picked within a couple of weeks, weeds may start growing and cotton will leaf out under good moisture conditions. This results in extra expense and in some cases another defoliant application.

Any weather event after defoliation will usually result in some lint being lost, and a tropical storm can result in seed sprouting in the bolls, creating lower grades. There is little that producers can do about a hurricane but be timely on the things that they can control.

Our model for hardlock indicates that this may be a bad year for hardlock again in the Deep South. The factor that could have reduced that impact would have been insecticide and fungicide sprays during bloom period.

If you have fields with bad hardlock/ boll rot this year, consider insecticide/fungicide applications during bloom on those fields in other years but split fields, leaving check strips so that you can determine if it is worth it on your own farms.

Glen Harris

Knock on wood. After getting significant rainfall from Tropical Storm Fay in late August, Hurricanes Gustav and Ike totally missed the Georgia Cotton Belt. Except for some damage from excessive rainfall in a few southern tier counties, Fay actually provided the late (June)- planted cotton in Georgia with some much needed rain.

The predominately dry weather earlier, followed by rainfall from Fay, apparently created conditions that caused a large outbreak of leafspot disease on cotton in Georgia and throughout the Southeast. This condition is thought to be linked to potassium deficiency, and, in fact, the leafspot incidence is thought to be a secondary problem caused by this nutrient deficiency.

High fertilizer prices at planting and the possible cutting back of soil-applied potash are also thought to have contributed to this problem. Even when adequate potash was supplied in soil and/or fertilizer, dry conditions may have reduced the ability of the plants to take up potassium when needed.

Fungicide applications were made in some situations in an attempt to curb the spread of the disease. However, if the potassium deficiency was not corrected, fungicide applications may not have been effective. Foliar feeding potassium may have helped reduce the spread of disease and saved some yield potential in cases that were not too severely affected.

Keith Edmisten

In North Carolina, we need to keep in mind that cool weather is on the horizon. Defoliants, of course, work better in warmer weather. Fortunately, we usually have a warm spell the first or second week of October. That may be our last chance at a decent window of weather for defoliation. This is particularly true for hormonal defoliants.

Regrowth control offered by several hormonal products that include thidiazuron, the active ingredient in Dropp, is less likely to be needed at this point as weather is less likely to favor regrowth. However, hormonal products containing ethephon that help open bolls may be very beneficial to get this crop open before frost occurs. We need to take advantage of warm periods when these products will work the best.

Products containing ethephon also enhance defoliation. Defoliation with mixtures containing ethephon can speed up abscission zone development. We sometimes see that defoliation applications made only a few days prior to frost are more likely to drop leaves rather than stick leaves if some form of ethephon is used.

Randy Boman

Heat unit accumulation in the first half of September in the High Plains left us considerably behind in terms of crop maturity. With the significant rainfall in September and cooler growing conditions, we badly need a late season boost from Mother Nature. Verticillium wilt disease issues are being noted. Dr. Jason Woodward, Texas AgriLife Extension Service plant pathologist, has noted that root knot nematodes (RKN) have been a challenge in many sandyland fields in the High Plains.

RKN symptoms include stunted plants with chlorotic leaves and fewer bolls. This can also resemble nutrient or water deficiencies. The female nematode establishes herself in the cotton root and modifies cells to support reproduction. This results in the formation of galls. Approximately 500-plus eggs/female can be deposited during a single life cycle, which may be completed in as little as 30 days.

Several life cycles can be completed within a growing season. Some fields in the High Plains also are infested with reniform nematodes. Symptomology is somewhat similar to RKN, as the reniform causes severe stunting and chlorosis, and the infected plants may wilt. Overall, reduced root growth is noted. The females invade roots (with the head), and the body protrudes from roots becoming swollen (kidney-shaped).

The reniform nematode life cycle from egg to egg is 20-30 days. Now is a good time to sample infested fields properly. Producers should take three composite soil samples per field, beginning in early fall. Twenty core samples per composite sample is best. Sampling patterns could be systematic, random, or zig-zag. Each core should sample down to the 12-inch depth. It is best to collect a composite sample for each one-third of the field. For more information regarding nematode sampling or management, contact personnel at the Texas AgriLife Research and Extension Center at Lubbock (806-746-6101).

Darrin Dodds

If any year can be considered normal, 2008 will probably not be remembered as such. Early spring rains caused significant planting delays in many areas of the state. Delayed planting was followed by nearly two months of dry weather, which was followed by several hurricanes that produced tremendous rainfall over the past several weeks.

As a result, reports of boll rot and hardlock were widespread. However, as I write this report in mid-September, defoliation has begun and will kick into high gear over the next 7-14 days.

Prior to the recent rainfall, yields were expected to be above average and, in some cases, outstanding. Unfortunately, due to weather conditions over the past several weeks, high yield expectations were replaced by the desire to put the 2008 crop into the books.

As is always the case, finishing one crop means it is time to start planning for the next. With record fertilizer prices, it is more important than ever to utilize a sound soil fertility program. The cost of a soil sample collection and analysis is a small investment that could pay large dividends next season.

Robert Lemon

With the high cost of fertilizer today (and getting higher daily), producers and practitioners have been asking lots of questions about fertility and nutrient management issues. Unfortunately, based on my informal surveys at several meetings recently, it doesn’t appear that we’re adhering to the most basic fertility best management practice – soil testing! Soil testing always has been, and continues to be, the foundation for building a strong nutrient management program. Setting a realistic yield goal and then applying only the amount of fertilizer needed to meet that goal is imperative. Setting too high a yield goal can lead to over-application, which is undesirable, both for economic and environmental reasons.

Last time I checked, urea ammonium nitrate was about $560 per ton or $0.88/pound of nitrogen, and a comprehensive soil test was about $30. So, if you’re not soil testing – start. It could be the best $30 you’ve ever spent

Bob Hutmacher

After a difficult production year, a warm and extended fall could sure help mature some late-developing bolls and provide a boost in yields. Hopefully, there will be some good yield surprises to go along with the less desirable outcomes.

Yields are expected to be highly variable across cotton fields in the SJV, with what look like some fairly good yields in fields that missed heavy lygus pressure, and some heavily impacted fields with much lower yields.

Many fields have some large gaps in fruit set, most associated with pest pressure, with some additional losses due to later season high temperature damage and/or water stress associated with irrigation delays. Favorable conditions in September and October could help out the top crop and make up for at least some of those earlier losses.

Before you put away field notes on problem areas of fields for the year, you might also make sure problem weed species and weedy areas are documented to improve future weed management activities. As expenses for nearly everything keep going up, it might help if you took a little time to identify specific field areas where targeted, more intensive weed control efforts could pay off.

If problem weeds are approaching, be sure to consider alternative crop rotations where other approaches and chemicals can be used to get situations under control before going back to cotton. If you are a Pima grower, you still have a while to wait for transgenic, herbicide-resistant commercial Pimas, so it is important to have a balanced weed management program.

At this time just moving toward harvest, it’s also a good practice to look at weak areas of fields, particularly if poor growth resulted in low yields. Identify if there are some cost-effective practices to consider, whether it is addressing fertility or salinity problem areas, water penetration problems or how to deal with water availability.

Randy Norton

The 2008 harvest season is upon us in the great state of Arizona. The western part of the state has successfully harvested its crop and by all indications it was a better- than-average year for the producers along the Colorado River. Central and eastern Arizona are on the front end of the harvest season with what we expect to be an average-to-above average crop.

This summer was fairly mild with limited heat stress events contributing to a more uniform fruit load on the crop. Insect pressure was more prominent this year than in the previous two years. Treatments to control whitefly populations were imposed across central Arizona while control measures for lygus populations were employed in both central and eastern Arizona.

As we progress through harvest, many find it to be a good time to evaluate the inputs into the 2008 crop, particularly if you have a lot of ‘seat time’ on a cotton picker. Basically, there are two general strategies often evaluated in attempts to realize a profit. One strategy is to ‘push’ the crop in an effort to increase yields dramatically. This technique often involves significant increases in inputs such as water, fertilizer, pest control, etc.

Increased yield may be realized but not always to the level of covering increased costs of production. The other strategy involves maintaining or slightly increasing yields while reducing production costs associated with the crop. In the current economic climate, many producers are wisely pursuing the latter option.

Increased costs of energy, fertilizer, seed and technology have forced producers to examine carefully decisions that will be made regarding these inputs and practices.

It is critical that every input or production practice be scrutinized and evaluated with respect to its cost/benefit relationship, including everything from tillage practices to the decision of whether or not to use transgenic technologies.

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