Codling Moth Activity in Walnut Orchards

Tim Hammerich

News Reporter

Codling moth is a significant pest in walnut orchards. Growers, PCAs, and extension have all been trapping the pest since March to get an indication about how severe each of the first two flights are of the pest. UC Cooperative Extension IPM advisor Jhalendra Rijal, says populations have been low in the first two flights so far this season.

Rijal… “The majority of my traps and then all the majority of the pest control advisors in our area, Northern San Joaquin valley. For first flight, second flight, there is very, very low activity off codling moth. So in other words, based on those numbers, there is no need for any kind of treatment. And if we go to the third flight, that number can jump up and there might be need for that third flight. So the trapping and then doing the monitoring, really is actually helping not to spray and if we need to spray and make a decision when to spray. That's the very foundation of the IPM, right? Integrated pest management is about that. We decide based on when to spray or whether there is a need for the spray or not.”

Rijal says the third flight, which starts in August, could still be above economic thresholds even though the first two flights have not been significant. He says codling moth monitoring and management requires discipline throughout the growing season for effective integrated pest management.