How to Manage Pests

UC Pest Management Guidelines


Pheromone Traps

(Reviewed 6/10, updated 6/10)

In this Guideline:

In nectarines, pheromone traps are used to monitor adult emergence and flights of San Jose scale and certain moths including oriental fruit moth, omnivorous leafroller, peach twig borer and obliquebanded leafroller.

Use the information obtained from trap catches to schedule control actions when used in conjunction with degree-day calculations. The traps are used to establish a biofix—an identifiable point in the life cycle of the pest at which you can begin degree-day accumulation or take a management action. For example, the biofix for peach twig borer is the date that the first adult moth of each generation is caught.


  • Place traps in each orchard for which you need to make pest management decisions.
  • Traps should be placed in orchards by the dates indicated in the table below.
  • Use at least 2 traps per block for moths, and 3 or 4 per block for San Jose scale.
  • Distribute the traps uniformly throughout the orchard and use the same locations each year.
  • Place additional traps in hot spots for specific pests.
  • Hang traps 6 to 8 feet high, 1 to 3 feet inside the canopy in the north quadrant of the tree, in the shade, and at least 5 trees in from the edge of the orchard.
  • Check traps twice a week until the biofix is established; thereafter, check traps weekly.
  • Remove trapped insects from the trap bottom after you count and record trap catches on a monitoring form (49 KB, PDF).
  • Replace trap bottoms monthly or when they become covered with debris.
  • Follow manufacturer's recommendations for replacing pheromone dispensers.
  • Store pheromone dispenser in a refrigerator or freezer.


Pest Where and when Importance
oriental fruit moth February 15 Detect first moth emergence to know when to start degree-day accumulation
San Jose scale February 25 Detect males to start degree-day accumulation

omnivorous leafroller February 20 Detect moth emergence to start degree-day accumulation

peach twig borer March 20

Detect moth emergence to start degree-day accumulation
obliquebanded leafroller April 15 Detect moth emergence to start degree-day accumulation



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Nectarine
UC ANR Publication 3451

General Information

W. J. Bentley (Crop Team Leader), UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare County
R. A. Duncan, UC Cooperative Extension Stanislaus County
S. Johnson, Pomology, Kearney Agricultural Center, Parlier
J. A. Roncoroni, UC Cooperative Extension, Napa County

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