04Cotton Insects

Cotton Insects Overview

Course: EPP 4234/6234

Global Cotton Production

• Total Production: 119.1 million bales from 82 million acres.

• Key Producers:

  • China: 8.3 million acres, average yield 1621 lb/ac, producing 27.8 million bales.

  • India: 31.6 million acres, average yield 419 lb/ac, producing 27.6 million bales.

  • US: 10.2 million acres, average yield 864 lb/ac, producing 18.3 million bales.

• Data Source: USDA Foreign Agricultural Service (2017-2021 average).

US Cotton Production

• Total: 10,220 thousand acres with average yield of 864 lb/ac, producing 18,300 thousand bales.

• State Breakdown:

  • Texas: 4,730 thousand acres, 709 lb/ac, 6,970 thousand bales.

  • Georgia: 1,260 thousand acres, 864 lb/ac, 2,260 thousand bales.

  • Mississippi: 580 thousand acres, 1073 lb/ac, 1,300 thousand bales.

  • Arkansas: 500 thousand acres, 1184 lb/ac, 1,250 thousand bales.

• Data Source: USDA National Agricultural Statistics Service (2017-2021 average).

Cotton Cultivation Practices

• Plant Characteristics:

  • Cotton is a perennial plant managed as an annual.

  • Varieties:

    • Upland Cotton (Gossypium hirsutum) mainly cultivated in MS and across most of the US.

    • Pima Cotton (G. barbadense), predominantly in CA and some in AZ, NM, TX; known for extra-long fiber length.

• Yield Statistics:

  • Average lint yield ranges from 800-1200 lb/ac, with some fields exceeding 3 bales/ac.

  • Lint fraction turnover is between 35-43%. Current value per lb lint is $0.80-0.95 based on quality.

Cotton Planting Guidelines

• Population Density: Desired population is 35-40,000 plants per acre (approximately 2.5-3 plants per row ft on 38" rows). Recommended seeding at 3-4 seeds per row ft.

• Row Width Options:

  • Standard: 30-40 inches

  • Ultra-narrow: 7-15 inches

• Planting Depth: ½ to 1 inch.

• Optimal Planting Conditions: Soil temperature should be above 65°F by 10 AM with warm weather forecast; typically, planting occurs between late April to late May in MS.

• Growing Degree Days: Utilizes a base of 60°F without a maximum temperature (DD60).

• Irrigation Methods: Includes irrigated systems (furrow and overhead) and non-irrigated practices in MS.

Cotton Development Stages

Emergence to Cutout

• Emergence: 4-10 days from seeding, approximately 50-60 DD60s required.

• First Square Formation: Occurs about 32 days post-emergence (around 450 DD60s).

• Bloom Timeframe: Interval from first square to first bloom takes 23 days (325 DD60s).

• Cutout: The plant halts energy expenditure on new squares after reaching node NAWF5, typically occurs around 80 days post-planting.

• Maturity Timeline: From planting to maturity takes around 150 days (2200 DD60s).

Pest Management

Major Cotton Pests

• Before Squaring:

  • Major: Thrips.

  • Minor: Spider mites, soil insects, cutworms, cotton aphids, slugs.

• During Squaring:

  • Major: Tarnished plant bug, boll weevil (pre-eradication), bollworm, tobacco budworm.

  • Minor: Spider mites, aphids, cotton fleahopper.

• After First Bloom:

  • Major: Plant bugs, boll weevil (pre-eradication), armyworms, loopers, stink bugs.

  • Minor: Spider mites, aphids, fleahoppers, whiteflies, saltmarsh caterpillar, webworms.

Specific Pest Information

Thrips

• Identification: Slender, spindle-shaped body; varying species include Tobacco thrips and Western flower thrips.

• Life Cycle: Females lay eggs in plant tissue; eggs hatch in 3-20 days, with multiple generations possible each year.

• Damage Symptoms: Feeding leads to holes in leaves, silvery appearance, crinkled leaves, and reduced growth.

• Management: Utilize sampling techniques and insecticides when viability thresholds are crossed.

Spider Mites

• Species: Twospotted spider mite and Banks grass mite.

• Lifecycle: Continuous generations; capable of rapid population growth under warm, dry conditions.

• Damage: Wilting and chlorosis of leaves, webbing on leaves; needs a threshold for treatment monitoring.

Pest Control Strategies

• Cultural Controls: Adjust planting variety, manage field borders, and proper timing.

• Biological Controls: Includes natural predators and parasitoids, ensuring populations of beneficial insects.

• Chemical Controls: Careful selection of insecticides, considering resistance issues across pest populations.

Conclusion

Understanding the complexities of cotton insect management is critical for optimizing yields and minimizing pest-related losses. By following proper cultivation, planting, and pest management guidelines, growers can improve cotton health and production outcomes.

Major Cotton Insects

1. Thrips

• Scientific Name & Family: Frankliniella occidentalis (Western Flower Thrips, Thripidae)

• Generations per Year: Multiple generations possible each year.

• Damage: Feeding leads to holes in leaves, silvery appearance, crinkled leaves, and reduced growth.

• Overwintering: Eggs laid in plant tissue; adults may survive in debris or alternate hosts.

• Control Strategies: Utilize sampling techniques and insecticides when viability thresholds are crossed.

2. Spider Mites

• Scientific Name & Family: Tetranychus urticae (Twospotted Spider Mite, Tetranychidae)

• Generations per Year: Continuous generations, rapid population growth under warm, dry conditions.

• Damage: Wilting and chlorosis of leaves, webbing on leaves.

• Overwintering: Eggs may survive in leaf litter or soil; adults can also hibernate in protected locations.

• Control Strategies: Monitor thresholds for treatment; consider natural predators and proper irrigation to manage populations.

3. Tarnished Plant Bug

• Scientific Name & Family: Lygus lineolaris (Tarnished Plant Bug, Miridae)

• Generations per Year: 2-3 generations.

• Damage: Feeding causes distortions in flower and fruit development, stunting plants.

• Overwintering: Can overwinter as adults in debris or leaf litter.

• Control Strategies: Scout fields, use insecticides selectively, and encourage beneficial insects.

4. Boll Weevil

• Scientific Name & Family: Anthonomus grandis (Boll Weevil, Curculionidae)

• Generations per Year: 2-3 generations.

• Damage: Larval feeding inside buds and bolls leads to damage and reduced yield.

• Overwintering: Adults burrow into the soil or remain in crop debris.

• Control Strategies: Eradication programs, monitoring traps, and insecticide applications.

5. Bollworm

• Scientific Name & Family: Helicoverpa zea (Bollworm, Noctuidae)

• Generations per Year: Multiple generations possible during the growing season.

• Damage: Feed on bolls and flowers, leading to direct yield loss.

• Overwintering: Can migrate and overwinter in warmer climates; pupal stage can survive in soil.

• Control Strategies: Utilize resistant varieties, insecticides, and biological controls such as Bt (Bacillus thuringiensis).

6. Tobacco Budworm

• Scientific Name & Family: Heliothis virescens (Tobacco Budworm, Noctuidae)

• Generations per Year: Multiple generations possible.

• Damage: Feeding on buds and blooms, causing developmental damage.

• Overwintering: Overwinters primarily as pupae in the soil.

• Control Strategies: Monitor and apply insecticides when thresholds are met; encourage beneficial arthropods.

7. Armyworms

• Scientific Name & Family: Spodoptera spp. (Armyworms, Noctuidae)

• Generations per Year: Multiple generations throughout the year.

• Damage: Chewing damage on leaves; can lead to defoliation.

• Overwintering: Pupae survive in the soil or migratory behavior to warmer areas.

• Control Strategies: Field scouting, use of insecticides when needed, and cultural practices.

8. Stink Bugs

• Scientific Name & Family: Acrosternum hilare (Southern Green Stink Bug, Pentatomidae)

• Generations per Year: 1-3 generations; depends on environmental conditions.

• Damage: Feeding can cause discoloration and drop of cotton bolls.

• Overwintering: Adults overwinter in protected areas like debris or buildings.

• Control Strategies: Use of insecticides and promoting beneficial insects for control.