SUPPRESS® herbicide EC, a product manufactured by Westbridge Agricultural Products, was registered in California in 2015. Its active ingredients are Caprylic Acid and Capric Acid. It is registered for use in organic production, and it is labeled for use in “agricultural food and non-food crops”. In rice, it can be utilized only when the field is drained (no standing water allowed).

Since 2019, UCCE Rice Advisor Whitney Brim-DeForest has been testing SUPPRESS® herbicide for use in weed control in rice. In 2019, she collaborated with Jim Cook (Colusa County Farm Supply), to spot spray weedy rice in a field containing Type 3 (long awns, straw hulled). The application was made with a handheld backpack sprayer, at the highest labeled rate. The timing was too close to heading, however, and some of the weedy rice plants recovered.

This past season, in 2020, we did further testing in the field, on several different weedy rice types (field was a mix of Types 1, 2, 3, and 5). The application timing for the field testing in 2020 was made with a handheld backpack sprayer, at the highest labeled rate. The timing was approximately at panicle initiation, and at two weeks after application, the weedy rice plants were 100% controlled. At harvest, there was some regrowth, but none of the plants produced viable panicles.

For use in weedy rice spot spraying in 2021, SUPPRESS® could be an option, but the label does not allow for application when there is standing water in the field. Therefore, in order to be used, the field will need to be drained before application. Application timing is after the last grass herbicide has been applied, but before the weedy rice has started to flower (generally no earlier than 60 days after seeding). Reflooding is recommended within 48 hours of application to reduce the germination of additional weeds, unless the field can remain drained until harvest.

Remember to always follow all label instructions when applying any pesticide, as the label is the law. Make sure to pay particular attention to the Use Precautions and Restrictions. Consult your local Agricultural Commissioner's Office regarding buffer zones and aerial restrictions, before making any applications.

Label: https://westbridge.com/products-pdf-documents/SUPPRESS_Herbicide_Label_161109.pdf

SDS: https://westbridge.com/products-pdf-documents/SUPPRESS_Herbicide_SDS_2015.pdf

For more information, contact UCCE Rice Advisor, Whitney Brim-DeForest (wbrimdeforest@ucanr.edu), and Roberta Firoved, Industry Affairs Manager for the California Rice Commission (rfiroved@calrice.org) 

University of California Cooperative Extension Sutter-Yuba-Colusa is holding a series of webinars in September and October to provide research updates on some of the major crops in the Sacramento Valley. The classes are relevant to growers throughout California and are primarily focused on pest management and pesticide safety. 

The September 9th webinar will feature Franz Niederholzer, Orchard Systems Advisor. "We will be reviewing proven almond IPM practices with an eye to reducing input costs, where possible, while delivering effective pest control," says Niederholzer. He has been working in almonds in the Sacramento Valley for almost 20 years. 

Amber Vinchesi-Vahl, Vegetable Crops Advisor, will give her webinar on September 16th. She states, "I will be providing information on important pest issues in vegetables and the latest research updates on disease and weed management in processing tomatoes and cucumber beetles in melons." Her research on tomatoes covers cultivator trials for within-row weed control and monitoring of soilborne fungal pathogens.

Whitney Brim-DeForest, Rice and Wild Rice Advisor, will present September 30th. "The webinar will provide an opportunity for discussion and interaction about weed identification," she says. "We will also cover the latest research updates on specific weed species, resistance management, and new herbicides in rice." The information is relevant to both organic and conventional rice growers, so all are encouraged to attend.

The final webinar will take place on October 7, and will be given by Sarah Light, Agronomy Advisor. Light says, "We will cover opportunities to decrease environmental risk through pesticide selection and application, accurate diagnosis, and reduction of loss to the environment." 

Enrollment is limited, so register early. The cost is $20 for 1, $35 for 2, $50 for 3, and $60 for 4 webinars. For more details or to register, visit http://ucanr.edu/syc-uccevirtualwebinars. DPR CE credits have been approved (4 "other" hours total, 1 per class), and CCA credits have been approved for IPM credits (4 hours total, 1 per class).  

If you have questions, contact Whitney Brim-DeForest [wbrimdeforest@ucanr.edu or call the UCCE Sutter-Yuba office at (530) 822-7515].