Mid-June Armyworm and Weedy Rice Updates

Mid-June Armyworm and Weedy Rice Updates

The number of armyworm moths trapped in Sacramento Valley rice fields continues to grow.

Here’s the latest update from University of California Cooperative Extension Rice Farm Advisor, Luis Espino:

Week of June 15

On average, we are getting 20 moths/day in the traps. This is double what we were getting last week.

Graph: Average Moth Capture Sacramento Valley

We found the first worms in the four fields we are monitoring. On average, we found 2 very small worms per field, a little smaller than half an inch (see the picture below). Head capsule measures indicate that worms range from second to fourth instar, but they are mostly third instar. It took three persons searching for 30 minutes in each field to find these worms. This shows you how difficult they are to find at this point.

The degree day model predicts that these worms should reach the 5th instar starting in June 22. This would be a good time to increase monitoring of fields. 

For more information, click on the link below for the Armyworm Monitoring Website.

Meanwhile, there’s a new member of the UC Weedy Rice Team: Troy Clark. Here’s more from the Cooperative Extension e-newsletter:

Troy Clark will be working with us this summer visiting fields where weedy rice is known to occur. He will update the extent of the infestation, collect samples, and pull out as many weedy rice plants as possible. Troy is a graduate of CSU Chico where he obtained a degree in Land Resource Management. He has rice experience and is eager to contribute to the weedy rice team.

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Intrepid® 2F Armyworm Label Update

Intrepid® 2F Armyworm Label Update

You must have the Intrepid® 2F supplemental label in hand as if it were on the container. Intrepid® 2F is the only product with the active ingredient methoxyfenozide registered for use to control armyworm on rice. The registration was complete earlier this year, which left the registrant (Corteva Agriscience) no time to include rice on the label. Corteva Agriscience has made the supplemental label available on the CDMS and Agrian websites. For permitting and label questions, please contact your local agricultural commissioner’s office.