Tent-shaped pheromone trap.
Placing pheromone lure into wing-type trap.

Pheromone Traps

Pheromone traps are used to monitor the flights of certain pest moths and San Jose scale. In almond orchards, use pheromone traps to monitor San Jose scale and flights of peach twig borer.

Information obtained from trap catches can be used 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.

Monitoring until biofix is essential. Continuing to monitor after biofix will give you more information about the development of San Jose scale and peach twig borer in your orchard.

General guidelines for using pheromone traps:

  • Put up traps for:
  • Place traps in each orchard for which you need to make pest management decisions, using at least 2 traps per block for moths, and 3 or 4 traps per block for San Jose scale.
  • Distribute traps uniformly through the orchard. Use the same trap locations each year. Place additional traps in hot spots.
  • Hang traps in the shade, 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 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 the pheromone trap and degree-days monitoring form(PDF).
  • Replace trap bottoms monthly or when they become covered with debris.
  • Follow manufacturer’s recommendations for replacing pheromone dispensers. Store dispensers in a refrigerator or freezer.

Important links

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