December 2018
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Weedy Rice Update
An e-newsletter from the
University of California Cooperative Extension
End of 2018 Season Summary
This season, we were contacted by many growers and PCAs to inspect plants that were suspected to be weedy rice. When the identification was difficult, we grew them in the greenhouse to determine if they were weedy or not. Of these, only five turned out to be weedy. The infestations in these fields ranged from a few patches to just one plant. Unfortunately, one of the five positive samples turned out to be a new type of weedy rice (pictured above). This new type, which we are calling type 6, has reddish awns early after heading, and black hulls at maturity. It is distinguishable from type 4 (which also has black hulls) by the height of the plants (type 6 is tall, type 4 is not).

Growers managing infested fields keep working to reduce infestations. In some infested fields we were not able to find any weedy plants this year. This doesn’t mean the fields are free of weedy rice, because seeds can survive in the soil for several years. However, it indicates that infestations are being reduced. This is very good news.

New seed regulations come into effect next year. All growers should plant certified seed or seed that has been through a quality assurance program. Research and experience shows that the use of certified seed is the best way to prevent the introduction of weedy rice into new fields and stop the spread in infested areas. 

Next year, we will continue to work with growers and PCAs to identify and reduce the spread of weedy rice in California. Thanks for your support.
Check out the UCCE weedy rice web page by clicking below
UCCE Contacts
Luis Espino
UCCE Rice Farm Advisor
Colusa, Glenn and Yolo Counties
Whitney Brim-DeForest
UCCE Rice Farm Advisor
Sutter, Yuba, Placer and Sacramento Counties

Michelle Leinfelder-Miles
UCCE Farm Advisor
Delta Crops

Kassim Al-Khatib
Weed Science Specialist, UC Davis

This e-newsletter was developed by the University of California Cooperative Extension with support from the California Rice Commission.