How to Manage Pests

UC Pest Management Guidelines

Cotton

Leafhoppers

Scientific Names:
Potato leafhopper: Empoasca fabae
Southern garden leafhopper: Empoasca solana

(Reviewed 5/13, updated 5/13)

In this Guideline:


Description of the Pests

Several species of leafhoppers may occur on cotton. The southern garden leafhopper is most common in desert valleys, and the potato leafhopper is most common in the San Joaquin Valley. Only these two species cause economic damage. The potato leafhopper generally appears in cotton fields near potato fields in the Arvin-Edison area of Kern County and near the Sierra Nevada foothills in northern Kern, Tulare, and Fresno counties. Outbreaks of the southern garden leafhopper are most common near sugarbeet fields in the Imperial Valley.

Both species are identical in appearance; they can only be distinguished by examining their reproductive organs. Adults are pale green, wedge shaped, 0.12 inch (3 mm) long, with inconspicuous white spots on the head and pronotum. Adults fly or jump when disturbed. Nymphs (immatures) also have green wedge-shaped bodies and run rapidly forward, backward, or from side to side when disturbed. Their unique movement plus their bright color and shape distinguishes them from lygus bug nymphs and other slower moving insects like aphids.

Damage

Adults and nymphs suck sap from veins on the undersides of mature leaves, mostly on the lower half of the plant. The midrib veins become roughened. Affected leaves may become distorted, leathery, and develop yellow or red blotches. Though rare, severe infestation may cause plants to shed squares and small bolls. Larger bolls may turn soft and spongy, and fail to mature. Other species cause leaf stippling.

Management

Natural enemies usually keep leafhoppers from building up large populations in cotton. However, if large numbers migrate to cotton from other hosts, treatment may be needed if extensive symptoms appear.

Monitoring and Treatment Decisions

There is no treatment threshold for leafhoppers. Before applying an insecticide, check for swollen, lumpy main veins on a sample of injured leaves to make sure the field symptoms are actually caused by leafhoppers.

Common name Amount per acre** R.E.I.‡ P.H.I.‡
(example trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, also consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
 
A. ALDICARB* 10–14 lb 48 90
  SELECTIVITY: High
  PERSISTENCE: Pest: Long NE:2 Short
  MODE OF ACTION GROUP NUMBER1: 1A
  COMMENTS: at layby by cultivation. Sidedress granules 8–16 inches to one side of the plant row, 2–6 inches deep. Do not graze or feed trash to livestock. Do not make more than 1 application at planting and 1 application after the crop emerges. Apply between March 1 and Sept. 1 only.
 
B. MALATHION 8E Label rates 12 0
  SELECTIVITY: Low
  PERSISTENCE: Pest: Short NE:2 Short
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Ground or air application
 
C. IMIDACLOPRID
  (Provado 1.6F) 3.75 fl oz 12 14
  SELECTIVITY: High
  PERSISTENCE: Pest: Moderate NE:2 Short
  MODE OF ACTION GROUP NUMBER1: 4A
  COMMENTS: A neonicotinoid. Foliar application. Do not exceed 0.31 lb a.i./acre/season.
 
D. ACEPHATE
  (Orthene 97) 4 oz 24 21
  SELECTIVITY: Low
  PERSISTENCE: Pest: Moderate NE:2 Moderate
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: An organophosphate. Do not graze or feed trash to livestock. Apply in water at 5–10 gal spray/acre by air or 10–25 gal spray/acre by ground. May induce outbreaks of spider mites.
 
E. DINOTEFURAN
  (Venom) 1–3 oz 12 14
  SELECTIVITY: Moderate to High
  PERSISTENCE: Pest: Moderate NE:2 Short
  MODE OF ACTION GROUP NUMBER1: 4A
  COMMENTS: A neonicotinoid. Kills lady beetles.
 
** Mix with sufficient water to provide complete coverage.
Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
* Permit required from county agricultural commissioner for purchase or use.
1 Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.
2 NE = natural enemies

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Cotton
UC ANR Publication 3444

Insects and Mites

  • L. D. Godfrey, Entomology, UC Davis
  • P. B. Goodell, UC IPM Program and Kearney Agricultural Research and Extension Center, Parlier
  • E. T. Natwick, UC Cooperative Extension - Desert Research and Extension Center, Imperial County
  • D.R. Haviland, UC Cooperative Extension, Kern County and UC IPM Program
  • V. M. Barlow, UC Cooperative Extension, Riverside County and UC IPM Program
Acknowledgment for contributions to Insects and Mites:
  • E. E. Grafton-Cardwell, Kearney Agricultural Research and Extension Center, Parlier
  • N. C. Toscano, Entomology, UC Riverside

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