How to Manage Pests

UC Pest Management Guidelines



(Reviewed 5/13, updated 5/13)

In this Guideline:


Grasshoppers can be occasional early season pests. In late summer and fall, grasshopper eggs are laid in grassy foothills, on ditchbanks, along roadsides and fence rows, in pasture areas, and in alfalfa fields. The eggs hatch in spring and the young nymphs feed on nearby plants. When wild grasses and other plants become dry, the grasshoppers migrate to irrigated croplands.


Grasshoppers feed on foliage, most often on the edges of fields near pasture areas or roadsides. They seldom cause economically significant injury.


Topical treatments are most effective; treating field borders may be adequate. Insecticidal baits are not effective in cotton itself but may be when applied to rangelands or other breeding grounds before grasshoppers migrate to crops.

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

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
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. MALATHION 8E 1.5–2 pt 12 0
  SELECTIVITY: Low      
 PERSISTENCE: Pest: Short NE:2 Short
  COMMENTS: Limited residual effectiveness.
B. NALED      
  (Dibrom 8EC) 0.5–0.75 pt 48 See comments
  SELECTIVITY: Low      
 PERSISTENCE: Pest: Short NE:2 Short
  COMMENTS: Apply before bolls open. Do not graze livestock in treated fields. Destructive of natural biological control. Tank mixing may affect selectivity and persistence of this material. Do not apply more than 5 pt/acre/season.
** 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



[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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