University of California Rice On-line
University of California Rice On-line
University of California Rice On-line
University of California
University of California Rice On-line

Armyworm Monitoring

2019 Armyworm Trapping

Update July 10

After reaching the peak, the number of moths per night is going down. In the field, most worms are finishing their cycle, and unless defoliation is severe, no treatment is necessary. Overall, this first flight of armyworms resulted in more worms than previous years in the field, without reaching outbreak proportions. However, several fields, especially late planted fields where rice was small, had to be treated to avoid damage.

This year I observed and got reports of parasitoids present in fields. Usually I see parasitoids during later in the season. It is unclear how much they can help control worms, but every bit helps. Also, in one field, I observed what seemed like a severe virus outbreak, causing significant worm mortality. The picture below shows what the typical worm killed by virus looks like; they hang on top of the leaf to help spread the virus.


I don't expect the number of moths or worms to increase until we get to the heading stage. We will resume the email alerts as soon as populations start going up again.

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Thanks to Corteva Agriscience for helping fund the 2019 armyworm trapping network.

I'm using the FarmDog app to keep track of sampling sites and moth counts.

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