EVENT:	UC Rice Pest Management Course 2021
DAY/DATE:	Friday, Sept. 10, 2021
LOCATION:	Hamilton Road Field (on West Hamilton Rd. between Hwy. 99 and Riceton Hwy., Biggs, CA)
EVENT TIME:	8:00 AM-3:25 PM (Check-in: 7:30-8:00 AM)
COST:	Non-student: $80/100; current student: $40/50

This year will mark the 4th rice-specific course at the Hamilton Road Field and the Rice Experiment Station in Biggs, CA. The UC Rice Pest Management Course 2021 will begin with an interactive field tour of the research plots (Hamilton Road Field) where attendees can get up close to the weeds and rice (BRING YOUR BOOTS!) The course will include hands-on weed identification sessions on emerging and mature weeds and a disease and pest ID session. In the afternoon, speakers will address several pertinent topics in CA rice, including regulatory updates, new herbicides for resistance management, diseases and pests research updates, and how to construct a weed management program. 

The course is a collaborative effort between UC Cooperative Extension (UCCE), UC Davis, and the California Rice Experiment Station (CRES.) “This course provides a strong foundation for weed and pest management in California rice, as well as a chance for interaction and discussion with researchers on the latest pests and pest control options for California rice systems” said Whitney Brim-DeForest, UCCE Rice Farm Advisor. The event is a great opportunity for pest control advisers, growers, industry, extension, and interested students to gain a deeper understanding of pest management topics that affect rice.

Enrollment is limited, so register early. The cost is $80 if received by 9/7/2021 and $100 if received after 9/7/2021 (if there is space.) The cost for current students with proof of student status is $40/$50. Online registration closes on 9/7/2021. If there is space, you can register onsite the day of the event. For more details or to register, visit http://wric.ucdavis.edu and click on RICE PEST MANAGEMENT COURSE.

CA DPR and CCA continuing education units pending approval.

If you have questions, contact Whitney Brim-DeForest [wbrimdeforest@ucanr.edu or (530) 822-7515.]

 

Date: August 3, 2021

Location: UCCE Sutter-Yuba Office

142A Garden Highway, Yuba City

 

Register here!

Free (lunch provided)

 

Meeting Agenda

9:00–9:30 am Research Updates 2020-2021 (Whitney Brim-DeForest, CE Rice Advisor)

9:30–10:00 am Weedy Rice Survey 2020 (Luis Espino, CE Rice Advisor)

10:00-10:15 am Weedy Rice Identification (Luis Espino, Whitney Brim-DeForest, CE Rice Advisors)

10:15–10:30 am —BREAK— (plants to view)

10:30–10:45 am Non-conventional Path to Pesticide Registration (Roberta Firoved, California Rice Commission)

10:45-11:00 am Preventing Spread of Weedy Rice with Certified Seed (Timothy Blank, California Crop Improvement Association)

11:00-11:15 am Weedy rice emergence under various environmental conditions (Liberty Galvin, PhD Candidate, UC Davis)

11:15 am —LUNCH—

 

This project is sponsored with funding from the California Rice Commission.

**CE credits (CCA, DPR) pending**

In 2017, I started getting reports of a watergrass biotype/species (Echinochloa spp.) that was difficult to control using our suite of herbicides registered in rice. At the time, I knew we had multiple herbicide-resistance in late watergrass (Echinochloa phyllopogon), so I initially just thought the resistant biotype was spreading, and had maybe gained resistance to additional herbicide modes of action. However, once I started visiting fields, it quickly became apparent that this was not late watergrass (phenotypically-speaking). It also did not appear to be barnyardgrass (Echinochloa crus-galli), although the Echinochloa species are notoriously difficult to identify, and phenotypically quite variable in nature.

We came up with a preliminary set of characteristics to distinguish this unknown biotype or species (we are unsure if it is a distinct species) from the typical barnyardgrass and late watergrass found in California rice fields. All were characterized by their seed size and awns (Table 1).

Table 1. Preliminary distinguishing characteristics of watergrass species in California rice fields, based on seed characteristics. 

Preliminary Identification	Seed Description
Late watergrass	Large size, no awns
Early watergrass	Large size, awned (all seeds)
Barnyardgrass	Small size, variably awned (some seeds have awns, some do not)
New biotype/species (unknown)	Small size, awned (all seeds)

In 2018, we collected 8 samples from the field, and used two late watergrass samples from known susceptible populations to use as controls. We conducted a screening in the greenhouse, to see if we could replicate what we were seeing in the field. Field rates of Cerano® (clomazone), Butte® (benzobicyclon+halosulfuron), Granite GR® (penoxsulam), and Bolero® (thiobencarb) were used as the early-season granular applications. Field rates of SuperWham® (propanil), Regiment® (bispyribac-sodium) and Clincher® (cyhalofop) were used to test for the late-season cleanup applications. In the greenhouse, all applications were made at the 1.5 leaf stage of the grass.

Results indicate that 8 of the 8 samples were not controlled (less than 50% by biomass, in comparison to the untreated controls) by Granite GR® or Butte®. 7 of the 8 samples were not controlled by Bolero®, and 6 of the 8 were not controlled by Cerano®. This closely follows what growers were stating had occurred in the field: the watergrass was escaping early-season control, and was then difficult or impossible to control with later-season herbicide applications. SuperWham®, Regiment®, and Clincher® controlled 8 of 8 samples (at least 60% control). However, since the greenhouse application was conducted at an early timing (1.5 leaf stage), it is possible that later applications in the field may be less effective.

For growers, the implications of this preliminary screening are that control of this new biotype/species will need to be prioritized early in the season. Possible treatments (keep in mind that these have not been field-tested and could cause phytotoxicity) could be: a stale seedbed using a non-selective herbicide; pre-plant Abolish® (thiobencarb) followed by Cerano® or Butte® or Granite GR®; Cerano® followed by Butte® or Bolero® or Granite GR®; or Butte® followed by Granite GR® or Bolero®. There is still a strong likelihood that a follow-up application may still be required later in the season, even with these early-season applications.

In 2020, more than 60 watergrass samples were collected from all over the rice-growing region. We will continue working on identification and conduct further herbicide screening this year. 

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)