Armyworm Monitoring

2026 Armyworm Monitoring Update

Week of June 22

Moth numbers have come down for the past two weeks. Worm numbers will peak this week. Scout in weedy areas and areas with thick stands near field borders; look for defoliation in lower leafs. If defoliation is higher than 25%, a treatment may be needed.

Graphic line chart: moth captures in Sacramento Valley peak mid-June (~50), then decline.

Armyworm trapping results by location

 

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Funding for the trapping is provided by the Rice Research Board and Corteva Agriscience.