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How to Manage Pests

UC Pest Management Guidelines

Trap for peach twig borer.


Pheromone Traps

(Reviewed 4/10, updated 4/10)

In this Guideline:

In peaches, 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 the trap catch 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 Sacramento Valley – February 20
San Joaquin Valley – February 15
Detect first moth emergence to know when to start degree-day accumulation
San Jose scale Sacramento and San Joaquin valleys – February 25 Detect males to start degree-day accumulation
omnivorous leafroller San Joaquin Valley – February 20 Detect moth emergence to start degree-day accumulation
peach twig borer Sacramento Valley – April 1
San Joaquin Valley – March 20
Detect moth emergence to start degree-day accumulation
obliquebanded leafroller Sacramento and San Joaquin valleys – April 15 Detect moth emergence to start degree-day accumulation



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Peach
UC ANR Publication 3454
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
J. K. Hasey, UC Cooperative Extension Sutter/Yuba counties
S. Johnson, Pomology, Kearney Agricultural Center, Parlier
J. A. Roncoroni, UC Cooperative Extension Napa County

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