How to Manage Pests

UC Pest Management Guidelines


Monitoring Spider Mites, Aphids, and Thrips (Seedling Cotton)

(Reviewed 5/13, updated 5/13)

In this Guideline:

Start sampling for aphids, spider mites, and thrips as soon as plants emerge. Go to the specific pest sections for more information on when to treat and treatment options.


  • Sample once or twice a week.
  • Walk down rows in four quadrants of the field.
  • Use a hand lens to examine the first true leaves or cotyledons of random plants looking for damage and insects and mites.


Thrips No treatment is generally required. Treat for thrips only if plants show poor growth, there is terminal damage, and thrips are present in significant numbers.
Mites Treat for mites before defoliation occurs and the mite populations are high.
Aphids Treat for aphids if high populations persist for 7 or more days.


[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Cotton
UC ANR Publication 3444

General Information

  • 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

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Statewide IPM Program, Agriculture and Natural Resources, University of California
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