Crop Profile for Cotton in Louisiana

Prepared, August 2002

In 2000, there were 2,633 farmers who planted 690,000 acres of cotton.

From 1998 to 2000, the planted cotton acreage in Louisiana increased from 535,000 to 690,000. The number of acres harvested during this period ranged from 525,000 in 1998 to 695,000 in 2000. The yield ranged from 586 pounds in 1998 to 633 pounds in 2000. The number of bales increased from 641,000 in 1998 to 910,000 in 2000. Differences in the production costs arise from the area within the state where cotton is grown, whether it is irrigated or non-irrigated, the soil type, etc. One hundred percent of the harvested cotton is processed into various textile products. A high percentage of the harvested cottonseed is processed into cottonseed oil. In 2000, the estimated value of the crop including seed was approximately $235,061,073.

Cotton is grown primarily in the eastern part of Louisiana known as the

Macon Ridge. The following chart indicates number of acres per parish:

There is a relatively small amount of cotton grown in the southwest region of the state.

Reduced tillage or no-till cotton provides growers an opportunity to reduce the potential for erosion and soil movement into surface water. These systems can also afford timelier planting. Two non-conventional systems recommended in Louisiana are stale-seedbed and no-till.

In the fall:

• Prepare the crop for early once-over harvest.
• Immediately behind the picker, cut and/or shred the stalks.
• Broadcast maintenance fertilizer (P and K) as required by soil tests.
• Form elevated rows on existing beds.
• If needed, deep tillage should be accomplished either as a rip and hip or as a separate trip before bedding.
• Install required water furrows.
• If a cover crop is used, seed it following the deep tillage and bed forming.

Spring:

• In early to mid-March, apply a burndown herbicide to the existing vegetation in the field.
• A second burndown as a spot treatment may be required 2-3 weeks later. All weeds must be dead at planting time.

Planting Time:

• Apply preplant nitrogen ahead of bed "knock-off".
• When soil temperature is favorable for planting, knock off the bed, and incorporate preplant herbicide.
• Apply preemergence herbicide behind the planter.
• Manage the crop with conventional tillage from this time until harvest.

In the fall:

• Cut cotton stalks at a 6-8 inch height to reduce planter obstruction in the spring. Shorter stubble will create problems. A flail shredder works best.
• Apply phosphorous and potassium fertilizer after cutting stalks. This can be applied in the spring.
• Determine if a compaction zone exists in the planting bed and consider in-row deep tillage if compaction is a problem.
• If needed, reestablish water furrows.
• If using a cover crop, plant it after performing the practices listed above.

Spring:

• In mid-February, scout for winter annual weed species that may require an application of 2,4-D.
• In mid-March, apply a burndown herbicide.
• Spot treat with herbicides, if needed, to ensure large weeds are not present at planting.
• If phosphorous and potassium fertilizer was not applied in the fall, apply the required amount (based on soil test) after the application of a burndown herbicide.

Planting Time:

• Because of the increased surface residue and crop stubble, close monitoring of seed placement, seed-to-seed contact, and seed covering/seed furrow closure is critical.
• Plant the crop when the soil temperature is favorable for planting. Consider the use of in-furrow fungicide, insecticide, and perhaps a starter fertilizer. Additionally, the use of a low-rate pyrethroid insecticide tank-mixed with a preemergence herbicide is suggested for cutworm prevention.
• Preemergence herbicides should be applied as a broadcast application.
• Nitrogen fertilizer can be applied with a liquid-fertilizer applicator to supply the preplant/at-planting portion of the nitrogen or it may be applied shortly after emergence of the crop. Subsequent nitrogen can be applied broadcast and incorporated through irrigation, or it can be applied as a sidedressing using a coulter applicator.

In Season:

• Sidedress nitrogen using a coulter applicator or water-in surface applied nitrogen.
• Apply post-directed herbicide under the cotton canopy using rates, materials, and timing similar to conventional-tilled cotton.
• Treat row middles and row shoulder areas with a herbicide to maintain weed control since cultivation will not be used in those areas. Hooded sprayer systems work well for this type of application.

Operations that should be accomplished include:

• Stalk destruction
• Phosphorous and potassium fertilizer incorporation
• Deep tillage (if required)
• Formation of rows (i.e., bedding)
• Establishing field drainage
• Bed knockdown and rebedding
• Final bed knockdown, herbicide incorporation, planting, and reinstallation of field drainage.

To reduce the number of trips across the field, consideration must be given to the sequence of the required tillage operations.

• To obtain maximum incorporation of fertilizer and to minimize the potential loss from erosion, the fertilizer application (P and K) should be made either ahead of the deep tillage in the fall or just prior to preplant tillage in the spring.
• To facilitate the bedding operation and improve bed height, disking or the use of a field cultivator (preferred) should occur just ahead of bedding.
• To avoid reestablishing hardpans after deep tillage, limit preplant disking
• operations or use alternative field preparation tools such as field cultivators.

Several alternatives can be used to obtain the desired end result. A suggested approach follows:

• Shred stalks or disk once anytime up to early April.
• If phosphorous and potassium fertilizers are to be applied without nitrogen
fertilizer, make the P and K application ahead of disking, field cultivator, or deep tillage (if deep tillage is required).
• Follow the fertilizer application with either a light disking, a field
cultivator, or deep tillage. Determine if deep tillage is required by probing the soil and/or examining the root system of the previous year’s crop (if not already destroyed).
• Bed the field (i.e., form elevated rows) before the tilled soil is firmed by rain. Liquid or granular preplant nitrogen can be applied just prior to the bedding operation if the bedding occurs before April 1. The nitrogen application should be delayed until the rebedding operation, which is normally required just ahead of planting. Install the required water furrows after the initial bedding operation.
• One to two weeks prior to planting, knock down the beds just enough to remove existing vegetation and then rebed. If nitrogen was not applied in the initial bedding operation, it should be applied ahead of this knockdown and rebedding operation. Anhydrous ammonia can be applied during the rebedding operation.
• Install the required water furrows after rebedding. Initial nitrogen applications may also be made shortly after emergence of the crop

  If at this point (1-2 weeks before planting) the beds are still well formed from the initial bedding operation and are free of large vegetation, consider skipping the rebedding operation. Simply knockdown and plant when the desired conditions for planting occur.

Planting should not start until the soil temperature in the beds reflects a mid-morning temperature of 68° F (20° C) at a two-inch depth for three consecutive days, and there is a favorable five-day weather forecast. The soil temperature at a two-inch depth in the peak of a bed that has not been knocked down may be quite different from the soil temperature in the zone where the seed will actually be planted.

Attempting to specify exact planting dates by calendar is somewhat hazardous because of wide year-to-year variability. Generally, conditions favorable for planting do not occur before April 25. Normally, mid-April to mid-May should be considered as the first period favorable for planting over most of the state.

The desired plant stand is 2 to 3 plants per row foot (41,267 to 55,023 plants per acre) for cotton planted at the conventional row spacing of 38 inches. Often the uniformity of plant distribution within the row and across the field can have as much or more impact on potential yield than the number of plants per acre. The minimum stand recommendation is two plants per row foot or 27,110 plants per acre for 38-inch row cotton. On irrigated fields, it may be possible to accept fairly uniform stands as low as 1.5 plants per row foot or 20,633 plants per acre, but some yield loss is probable.

The majority of Louisiana cotton is produced under an integrated pest management (IPM) program. The LSU AgCenter Cooperative Extension Service personnel, private consultants, independent part time scouts, agricultural industry representatives, and producers provide the monitoring or scouting.

Integrated Pest Management is a sustainable approach to managing pests by combining biological, cultural, physical, and chemical tools in a way that minimizes economic, health, and environmental risks. IPM centers on the organization of a systems-type approach to the crop production plan. It is a management approach that relies, to the maximum extent possible and economically practical, on prevention or avoidance of the pest problems that are commonly encountered. Pest management practices include cultural control (e.g., transgenic cotton varieties), field monitoring/ scouting, mechanical controls, and use of naturally occurring, or in some cases, applied biological control agents. When satisfactory non-chemical controls are not available or fail to provide adequate control, chemical controls are applied as needed based on established economic thresholds for the pest(s).

Several insects attack cotton at various stages of growth. The primary insect pests in Louisiana are the bollworm (Helicoverpa zea), tobacco budworm (Heliothis virescens), thrips (Frankliniella spp.) and plant bugs (Lygus spp.). Secondary insect pests of cotton, which occur occasionally, include the beet armyworm (Spodoptera exigua), fall armyworm (Spodoptera frugiperda), cutworm (various species), aphid (Aphis gossypii), green stinkbug (Nezara viridula), brown stinkbug (Euschistus servus), and spider mite (Tetranychus urticae).

Insect populations vary depending on the area of the state where the cotton is produced.

The cotton boll weevil has historically been the key pest of Louisiana cotton. An eradication effort for this pest began in 1997. Boll weevils have been eradicated from several areas of the state. They are controlled by the Boll Weevil Eradication Program in the other areas of the state. The boll weevil’s high reproductive capability and resistance to several insecticides allow this insect to build up to large populations quickly. Forested areas around rivers, drainage ditches, and bayous provide favorable overwintering sites in southern cotton growing areas. Cooler winter temperatures and less favorable over-wintering habitats in the northern cotton growing areas cause higher mortality of overwintering boll weevil.

The bollworm and tobacco budworm species comprise what is commonly referred to as the Heliothine complex. Both species belong to the Noctuidae family of insects and attack cotton in a similar fashion. Both species occur as pests of cotton each year. Of the two species, the tobacco budworm is more difficult to control. Tobacco budworms have developed resistance to all major classes of insecticides. Both species can occur at extremely high densities (> 5 larvae/plant). Yield losses associated with this complex have been documented as high as 90% in individual fields.

Pest damage: The most obvious damage is feeding on squares and bolls, but bollworms and budworms can also reduce yields through secondary damage. Feeding damage often provides entry for disease organisms, which can lead to boll rot. This usually occurs in irrigated cotton, but it can occur in wet periods after rainfall.

Life cycle: Egg - 3 to 5 days; larva - 12 to 15 days spent feeding on cotton; pupa - 12 to 15 days resting in top two to four inches of the soil; adult - moths emerge from pupae and begin laying eggs in 3 to 12 days. The development of one complete generation may require from 27 to 35 days. Female bollworm moths can lay from 250 to 1,500 eggs. In a normal season, there usually are about six generations, but some of these are spent on plants other than cotton. Normally, only three to four generations inflict important damage on cotton. These worms overwinter in the soil in the pupal stage, after going through a preparation phase. Moth migration is common and moths may move many miles. Expect the first generation in early spring. At that time, the pests develop on legume crops, such as crimson clover or alfalfa. The second generation apparently prefers corn, where bollworms are known as corn earworms. Third generation worms generally are the first infestation for cotton, but insects also will infest corn or grain sorghum if these crops are present. If corn or sorghum is close by, the third generation may leave and migrate into cotton. Also, roadside plants such as evening primrose attract bollworms.

Light intensity, rather than the time of day, triggers bollworm and budworm behavior. On an average day, light intensity of 800 foot-candles, known to affect moth feeding, is reached at 4 to 5 p.m. Moths feed on nectar from flowers and the nectary glands of cotton. Aphid honeydew also is an attractive food, as well as water droplets. By 7 p.m., if the light intensity is around 28 foot-candles, moths are triggered into laying eggs, which may continue until 9 to 10 p.m. Some eggs are laid in blooms so newly emerged larva may feed inside the bloom. Blossoms may fold over the pests, so insecticide coverage failure can occur. Newly hatched larvae may feed on leaves the first day before attacking squares and bolls.

Critical timing of control measures: Treat when infestation levels reach 5% eggs and small larvae on non-Bt cotton or 2-3% live larvae on Bt-cotton.

Yield losses attributed to pest:

Chemical Control - Larvae and Adults

Cyfluthrin:

Thiodicarb:

Transgenic Bt cotton varieties.

Monitoring bollworm and tobacco budworm populations using pheromone traps.

Transgenic cotton (Bt-cotton) comprises 80% of the acreage planted and is effective in controlling the tobacco budworm. One hundred percent of Bt cotton acres receive an average of 1.5 yearly sprays of a pyrethroid insecticide for bollworm control.

Thrips are a common (i.e., yearly) problem for most cotton producers in Louisiana. Thrips infest cotton in the young seedling stage and severe thrips damage can stunt growth and reduce yield potential. As a result, most cotton is treated with an in-furrow insecticide to prevent the development of damaging populations and consequently thrips are rarely a devastating problem in Louisiana cotton.

Pest damage: Larvae and adults suck plant juices from the tender terminals. The first targets of thrips moving into early cotton are the seed leaves, which become distorted or crinkled. Feeding damage can reduce stands enough to force replanting in extreme cases. Thrips feeding also can set back stand maturity. In most cases, the seedlings can grow out of the first stage of damage. Where feeding punctures are numerous enough, cotton may be triggered into a period of erratic habit and growth.

Life cycle: Egg - 4 days; larva - 6 days, molting twice; pupa - 4 days; egg to adult - 14 days average. These pests overwinter in the pupa stage in plant trash. They begin reproducing in early spring in non-cotton host plants, such as grains, early blooming weeds, and legumes. Once the early host plants toughen, thrips move quickly into cotton fields. In many areas of the Cotton Belt, thrips migrate into cotton about the time wheat is cut. When the pests migrate, late-planted cotton is one of their chief targets since the crop is tender and offers easy feeding.

Critical timing of control measures: Must be treated early either with an in-furrow application at planting or a foliar application soon after the cotton plant emerges.

PLANT BUGS

Pest damage: All plant bugs have piercing mouthparts used to suck plant juices. Plant parts damaged include pinhead squares, squares, and bolls. Injury to pinhead squares will cause square to abscise. Injury to larger squares can impact pollination. Injury to bolls causes direct damage to lint and lint loss from boll rot.

Severe infestations often develop quickly because these pests may build up into a massive population on another host, such as alfalfa or corn. When the first host plant is cut or becomes tough, plant bugs migrate quickly into cotton and growers are faced with a full-blown plant bug problem just a day or two after checking clean fields. Flowers also are attacked by some plant bug species, causing warty growths on flower petals and brown spots on stamens and pistils. Plant bugs lay eggs inside cotton stems near the top of the plant. The pests usually lay very small eggs in groups that normally are impossible to detect.

Life cycle: The rapid plant bug and tarnished plant bug: eggs - 10 days; nymphs -15 to 20 days; number of life stages - 5. Clouded plant bug: eggs - 12 to 14 days; nymphs - 10 to 18 days; number of life stages - 5. All plant bugs are multiple-host insects and spend most of the season on other hosts, which they prefer over cotton. Tarnished and rapid plant bugs overwinter as adults in ground trash near host plants. The clouded plant bug overwinters in the egg state in the stems and stalks of host plants of various kinds. These pests are referred to as "true bugs" by entomologists because they do not pass through a larval or worm stage, and they do not go into the pupa or resting stage. When true bugs hatch, they resemble the adults except for size and often the absence of wings.

Critical timing of control measures: Vary treatment thresholds according to pre-bloom square set. During squaring, treat for plant bugs if square set is 70% or less, and plant bugs are present. For post-bloom cotton, treat when infestation reaches 10-15%.

Yield losses attributed to pest: The average yield loss due to plant bugs was 1.5% from 1996-1998. Yield loss estimates do not include the costs associated with controlling or managing the pest.

Thick stands of cotton tend to have increased numbers of plant bugs.

Aphids are a secondary pest in cotton. They tend to be a greater problem in reduced tillage cotton. In some years, aphids have caused severe problems for growers.

Frequency of occurrence: Aphids tend to be a frequent pest of a portion of Louisiana cotton each year.

Pest damage: Heavy infestations cause curling or crinkling of leaves. Aphids feed on the youngest, most tender growth and, when present in large numbers, will cover terminals. During the principal blooming period, aphids may cause older leaves to turn yellow and shed. Severe infestations can cause heavy yield/quality losses.

Life cycle: Female aphids give birth to live young. Females continuously reproduce without a male. The pests can multiply rapidly under high temperatures and may develop the equivalent of a new generation every 5 days.

Critical timing of control measures: Treat when populations are building and aphids are present on approximately 50% of the plants. Aphid treatments will be more effective when applied in combinations. Do not apply pyrethroids prior to July 1. Use systemic in-furrow insecticides at planting to suppress early season aphids.

The green, southern green, and brown stinkbugs have become problems in recent years. Stinkbugs can be found in the cotton all season. Recent research has shown that all pyrethroids are effective on green and southern green stinkbugs. However, control of the brown stinkbug is limited to methyl parathion, dicrotophos, and acephate.

Other secondary pests such as spider mites, cutworms, beet armyworms and fall armyworms occur sporadically throughout the state and do not occur in economically damaging numbers every year. Spider mite outbreaks occur along ditch banks and roadways where the spider mites overwinter on winter weeds and other host plants. Spider mites are a greater problem during growing seasons which average less than the expected rainfall. Cutworms attack newly emerged plants by cutting the young plant at the soil line. Most acres are treated at planting with a pyrethroid insecticide for cutworm control. Beet armyworms and fall armyworms occur primarily in Louisiana during late summer. Populations of beet armyworms and fall armyworms can build up to large populations by mid to late summer.

Several diseases are economically important in Louisiana cotton production.

Pathogen levels, seedling vigor, weather, and environmental conditions all affect the incidence and severity of disease each year. Most of the major cotton diseases are soil-borne and survive from year to year in the cotton field. The causal agents that cause seedling diseases include Pythium spp., Fusarium spp., Rhizoctonia solani, and Thielaviopsis basicola. These seedling disease pathogens may cause disease individually, or they may interact to form a disease complex that can be more severe than the individual pathogen effects. Symptoms of seedling disease include pregermination decay of the seed, decay of the seedling on the way to soil surface (preemergence damping off), partial or complete girdling of the emerged seedling at or near the soil surface, and seedling root rot.

Fusarium wilt (Fusarium oxysporum f. sp. vasinfectum) and Verticillium wilt

(Verticillium dahliae) both affect cotton in Louisiana. Fusarium wilt is often associated with the root knot nematode. This disease may be controlled to some degree using resistant varieties, although when nematodes are present even resistant varieties may exhibit moderately severe disease. Practices that reduce nematode populations in cotton along with the use of Fusarium wilt resistant cultivars are effective in managing this disease. Planting tolerant varieties, crop rotation, avoiding deep cultivation, and careful management of irrigation and nitrogen can reduce Verticillium wilt severity. Pesticides are not effective in the control of Fusarium or Verticillium wilts.

Trade name is Baytan (used as a seed treatment). Baytan is usually applied in

Three species of plant-parasitic nematodes occur in Louisiana that can cause economic yield losses to cotton. These are the reniform nematode (Rotylenchulus reniformis), the southern root-knot nematode (Meloidogyne incognita), and the Columbia lance nematode (Hoplolaimus columbus). Nematodes are estimated to be in 70-80% of the fields where cotton is produced each year.

Reniform nematode is the most important nematode in both its distribution and losses inflicted each year. Reniform is widespread throughout the state and is known to occur in all areas where cotton is produced. Early estimates of reniform nematode in the 1960s’ were three to four thousand acres. Reniform nematode is currently spreading throughout much of Louisiana and was estimated in 1995 to be present in at least 510,000 acres. Reniform nematode seems to prefer the silt loams that represent a large percentage of the acreage where cotton is produced in Louisiana but can successfully survive in either sands or clays. It is likely that this nematode will eventually be in almost 100% of the acreage where cotton is produced.

Root-knot nematode is the second most important nematode to cotton in our state. It is found only in sandy soils but is estimated to be in about 20% of our acreage. It is particularly destructive when present and has been showing up fairly severely on some of the newer genetically altered varieties or in rotation with corn. The Columbia lance is extremely limited in Louisiana and found only in a few fields in three parishes.

Yield losses to nematode is estimated at 8% during 2000. Losses can be broken down into 6% for reniform and 2% for root-knot nematodes.

Crop rotation works great against reniform and corn and grain sorghum are used extensively in fields with high populations of nematodes (>20,000 per 500 cm³). About 25% of the fields where reniform nematode are present have populations high enough that crop rotation should be used. Crop rotation is not nearly as useful against root-knot nematode and only a resistant soybean variety (very limited) works. Resistant varieties are not available against reniform nematode and limited (Paymaster 1560 BR) against root-knot nematode.

1,3 -dichloropropene:

The key to weed management in cotton is providing the seedling cotton plant with conditions that allow cotton to outgrow weeds, thus establishing a height difference for directed sprays. While preplant and preemergence herbicides must be used to control or suppress weed growth, the application of timely post-directed herbicides is often required to maintain a successful weed control program. Cultural practices that promote rapid germination and vigorous cotton seedling growth are very important in allowing timely postemergence applications. The weed species composition of the cotton crop is important in selection of the best weed control program. Proper identification of the weed complex will determine the best program to use.

Preplant herbicides are utilized to control several weeds including annual grass suppression, morningglory suppression, and seedling johnsongrass control. Preemergence herbicides are used to control the broadleaf complex including prickly sida, morningglory, and cocklebur. Postemergence herbicide applications are directed toward the control of grasses and broadleaf weeds including johnsongrass, annual grasses, cocklebur, and morningglory.

ANNUAL GRASSY WEEDS:

Frequency of occurrence: Annually.

Pest damage: Competition with the cotton crop for space, water, sunlight, and nutrients. In addition, weed seeds and plant residues in the harvested cotton can result in economic loss due to grade reduction.

Life cycle: Summer annuals

Critical timing of control measures: To best prevent cotton yield losses, annual grasses should be controlled as early as possible. Preplant incorporated and preemergence applications of these herbicides provide good early season control of the annual grasses. Postemergence applications of certain herbicides will also control the annual grasses that escape early season applications.

Chemical Control - Preplant Incorporated (PPI) Treatments for Grassy Weeds:

Chemical Control – Preemergence (PRE) Treatments for Grassy Weeds:

Chemical Control – Postemergence (POST) Treatments for Grassy Weeds:

Fluazifop + Fenoxaprop: