California Almonds, Walnuts: Trapping Options – Quick Overview

Navel orangeworm moth. Photo: L. Brian Stauffer, University of Illinois News Bureau

Moth and egg traps should be going up now in stone fruit, almond and walnut orchards in this part of the state. Here’s a brief overview on trap types and ideas on the best strategies for using them.

For nut crops, the use of the ovibait traps – wing or delta traps baited with ground almond or pistachio or any other kairomone to attract females – has become more common in the last several years. They tend to capture more mated and relatively older female moths.

Due to the potentially short active distance of the kairomone bait, wing traps perform better compared to the delta trap, although the latter is more user-friendly.

On one hand, the ovibait traps capture a smaller number of moths compared to the pheromone traps. On the other hand, ovibait trap information seems to be more reliable because those number more strongly correlate with almond crop damage. That is based on a study in the south San Joaquin Valley.

Also, the ovibait traps can be used to track NOW flight in orchards where mating disruption is being used. In those situations, pheromone traps are ineffective at tracking seasonal flights for those orchards.

A new type of lure, which has Phenyl Propionate (PPO) as the attractant, is now available with the commercial name NOW Female/Male Lure. It is intended for orchards where mating disruption is being used.

NOW pheromone traps, which attract male moths, can be used to track seasonal NOW activity in the orchard without mating disruption. If possible, position these in the almond orchard by mid-March.

In an orchard where NOW mating disruption is in place, use the pheromone trap in borders and also in low-lying areas to judge whether the mating disruption is working. In this case, little or no moth capture should indicate that mating disruption is functioning.

For codling moth monitoring in walnut orchards, put both 1x lure (standard 1-mg codling moth pheromone lure) as well as CM-DA combo lure (combination of codling moth pheromone and pear ester kairomone) by mid-March to determine biofix and start accumulating degree-days. The regular delta trap works fine.

Biofix (for codling moth) is the first date when moths are found consistently in traps, and sunset temperatures have reached 62°F.

Find more details here on the UCIPM website,


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