Alabama
Charles Burmester

Compared to many other crops, cotton is a very weak plant in the seedling stage. It is important to try to minimize the stresses on cotton at this time. Seedling diseases, thrips and weed pressure in this seedling stage often can affect the potential yield of cotton. We often forget how competitive weeds can be to seedling cotton.
In 1999, we had tests that measured more than 10 percent reductions in yield when weeds became competitive with cotton at the two and three leaf stage. Alabama research in the ¹70s found that, after emergence, cotton needed a six-week period in which weeds were not competitive. We need to remember this as we plan our weed control strategies this season.

Dale Monks

Early-season stresses in cotton fields can reduce stands, slow plant growth and delay maturity. The stresses most commonly encountered in the early season by Alabama producers include high thrips pressure, sandblasting, seedling disease, crusted soils and heavy weed pressure. These stresses should be dealt with quickly to avoid further delaying of crop development. Since sandblasting occurs most often where the soil surface is compacted and sealed by rainfall, the traditional treatment in northern areas of the state has been to use a single, shallow cultivation of the row middles. Sandblasting is greatly reduced in cotton that is planted no-till or row-tilled into a killed cover. The cover offers protection against the blowing soil particles and allows cotton to become established without this stress.
Early weed pressure also can affect plant growth for the rest of the season. With significant Roundup Ready cotton acreage in the state, the tendency is to delay the initial glyphosate application in Roundup Ready varieties to take full advantage of the weed control. According to research conducted by Dr. Mike Patterson, Extension weed scientist at Auburn University, delaying the initial application where weed pressures are excessive can reduce plant growth and make clean-up herbicide applications costly. The first application may need to be made earlier than the fourth true leaf stage to reduce the effects of weed competition.
http://www.acenet.auburn.edu

Arkansas
Bill Robertson

When we think of stress, we often think of factors detrimental to growth and yield potential. However, a good boll load is a stress with which everyone wants to be burdened. Minimizing and alleviating stresses are important in keeping plants on course toward earliness. Harmful stresses sometimes are difficult to detect in the early stages, and once they become more obvious, yield potential often becomes even more reduced.
COTMAN, a computerized program to assist in cotton management, can assist the producer or consultant in the detection of stress. Regardless of its source and prior to first flower, stress impacts the rate at which nodes are produced. SQUAREMAN, the early-season component of COTMAN, allows the user to monitor square retention and growth rates.
Comparing actual growth rates to that of a target can indicate if and when growth rates deviate from expected values. When plants begin to get off course, management decisions which take into account retention as well as growth rates can be formulated to get plants back on course and help plan for their future demands or needs. Early detection of negative stresses can allow for quick adjustments to correct problems in order to minimize negative effects on maturity and/or yield.
http://www.uaex.edu

Arizona
Jeff Silvertooth

Maintaining good fruit retention (FR) and strong plant vigor is dependent upon good water management (avoid water stress at any stage), good crop fertility (particularly N), proper PGR use and effective pest management.
Crop vigor can be evaluated by measuring representative plant heights (inches) and counting the total number of mainstem nodes, then calculating a simple height: node ratio (HNR). Reference of the measured HNRs to established guidelines, available through the University of Arizona Cooperative Extension System, provides an indication of crop status. Fields not retaining satisfactory fruit loads often will have relatively high and/or increasing HNR values and can be candidates for possible vegetative control efforts by use of plant growth regulators such as Pix.
University of Arizona guidelines concerning Pix applications on Upland and Pima cotton utilize HNR and FR information. Fields that are not gaining satisfactory structure usually will have low HNRs, and height control procedures should be avoided. Evaluate these fields for possible water stress conditions, including potential problems with water penetration and salinity.
http://ag.arizona.edu

California
Bob Hutmacher

Following a long, dry fall/early winter, most producers put on pre-plant irrigations to replenish depleted soil moisture. Rains in February and March added further help in providing seedbed moisture in most fields.
Under these conditions, availability of soil water in the upper soil profile shouldn¹t be much of a problem unless drying winds occur or early weed pressure depletes moisture. Even under these conditions, one of the best things you can do when you get close to the timing for the first in-season irrigation is do a little digging, looking at root system depth and distribution.
Ask yourself if you are starting the season with a normal root system, or is it more limited, requiring earlier and more frequent irrigations?
Timing of first irrigations can be important in avoiding damaging water stress, but there are a few things to remember in deciding timing of first irrigations: (1) most California research has shown that with fairly normal early tap root development, cotton is not very sensitive to water stress until after development of the first seven to nine main stem nodes; and (2) caution should be exercised in initiating early irrigations when weather remains cool, as irrigations cool the soil and can delay plant development.
During early to mid-squaring, you can begin to use leaf water potential measurements effectively to schedule irrigations, using University of California guidelines available from your UCCE Farm Advisors. If you instead use soil water balance scheduling methods, avoid depletion of more than 50-60 percent of available soil water during mid-square through most of the bloom period.
http://danr.ucop.edu or http://www.ipm.ucdavis.edu

Georgia
Steve Brown

Water/heat stress is inescapable in the Lower Coastal Plain of the Southeast. Drought is a continual threat. Ten days without rain during bloom means wilted cotton on light-textured, sandy soils. The past couple of seasons revealed (1) irrigation alone is insufficient to make a crop, and (2) aggressive irrigation at mid-square to early bloom may be detrimental.
With sustained drought and marginal subsoil moisture, we cannot supply the entire water needs of cotton with center pivot irrigation. An inch of rain is far better than an inch of irrigation water! On our sandy soils we cannot afford to fall behind in watering.
In 1999, we observed several well-irrigated fields with excessive early boll shed ... but with adequate fruit retention in the ³dry corners.² Slight stress during early bloom improved boll set. This is a fine line. If we delay too long, we risk fruit shed, premature cutout, or soil water depletion from which it may be difficult to recover.
These two issues seem contradictory. They underscore the fact that we lack understanding about irrigation. They further indicate that good management requires more than following a recipe but also includes careful observation and thoughtful reaction.
http://www.cropsoil.uga.edu

Mississippi
Will McCarty

For producers in Mississippi and the Mid-South, the major cause of plant stress is something out of our control ­ weather. As this is written we are very low in sub-soil moisture and farmers should manage to avoid early-season stress on the plants¹ root systems.
Early root development will be critical this season. Plant high quality seed into a warm soil and use the appropriate fungicide treatment. This is especially true where a systemic insecticide is used at planting. A systemic insecticide at planting will help reduce early-season insect damage and promote plant growth. This is especially true if one is used that has nematode activity.
Choose pre-emerge and early post-emergence herbicide programs carefully. Do not stress or stunt plants with excessive rates or over-the-top applications of material that can slow cotton growth. Avoid close or deep cultivation unless absolutely necessary.
Do not overlook drainage. It is critical that all field drains and water furrows be open and functioning. Wet soil will retard root growth.
Use caution in applying sidedress nitrogen. Do not make application too close to cotton plants. An average may be to split the difference and apply sidedress application half way between the drill and the bottom of the middle. Be especially careful with anhydrous ammonia, being sure the soil is sealing behind the applicator.
Early-season insect control is critical. Scout cotton twice per week and make applications to control damaging levels of pests as needed. Do not fall asleep at the wheel thinking that Bt cotton and boll weevil eradication programs will control all your insect pest problems.
Irrigated producers must be ready to apply water in a timely manner and in enough volume to help the crop. Irrigate the soil ­ not the crop. Keep your eye on the soil and keep moisture available to the plants. With the apparent shortage of sub-soil moisture, be prepared to begin earlier than normally practiced.
Pivot users should consider ripping non-traffic middles to increase water infiltration and perhaps reduce runoff. Considering fuel cost and water use efficiency is critical.
http://ext.msstate.edu

Missouri
Bobby Phipps

If a cotton crop is subjected to stress, its maximum yield potential is lost. Compare the growing season to a horse race. If the horse is off to a slow start or is held back for any reason, it is highly unlikely that it will win the race. It can regain speed but can not catch the rest of the pack. A crop may grow out of stress, but it can not catch up to where it should be at this point in the production season.
This means control as many stresses as possible. Some that can be controlled are thrips damage, which delays maturity and plant bug damage, which causes loss of squares that the crop will have to make up at the end of the season. This delays harvest and adds undue risk from weather. Stress from a low pH or a lack of nutrients can cause trouble during the entire season.
In a horse race, sometimes it is not good to get too far into the lead or the horse may tire before reaching the finish line. If the crop is growing too vigorously, it may be wise to control vegetative growth with mepiquat chloride.
Some stresses cannot be avoided due to the weather. Hail and low light conditions can play havoc with a crop. Excessive moisture can be very stressful. If these things happen, treat the crop gently for the rest of the growing season.
It is best to prevent crop stress rather than to try to cure it. An ounce of prevention is worth more than a pound of cure.
http://outreach.missouri.edu

Oklahoma
J.C. Banks