Delta Region Areawide Aquatic Weed Project

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2026 rice acreage and supply comments

July 15, 2026
By Sarah Marsh Janish
According to the June 2026 NASS Acreage Report, U.S. rice planted area fell sharply to 2.017 million acres, a 28% drop from the previous season and the lowest number of rice acres since the 1970s. The steep decline is largely attributed to severe weather issues (including localized moderate to extreme…
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Delta armyworm monitoring

July 15, 2026
By Taiyu Guan
Author: Michelle Leinfelder-MilesSeasonal monitoring for armyworms began in late-May in the Delta region. Our monitoring involves scouting for damage and deployment of pheromone bucket traps that catch the true armyworm moths. Traps are set up at three Delta locations, where at each location, there are three…
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Cultivating resilience: mental health resources for the ag community

June 8, 2026
By Sarah Marsh Janish
The demands of agriculture are unique, often blending long hours, unpredictable weather, and financial pressure. Taking care of your mental well-being is just as vital as tending to your crops. Whether you are looking for proactive stress management or need immediate support, there are resources specifically…
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Effects of azoxystrobin when disease pressure is low

June 1, 2026
By Luis A Espino
Azoxsytrobin (Quadris, Tetraban) is the most used fungicide on rice in California. Azoxystrobin has been in use since the late 1990s. This fungicide was registered after rice blast was discovered in California in 1996. More recently, several years of trials showed that when azoxystrobin is used at the late…
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Ongoing diesel exhaust fluid (DEF) action

May 25, 2026
By Sarah Marsh Janish
Background Since 2010, most on-road and many off-road vehicles and equipment have used selective catalytic reduction (SCR) systems to inject diesel exhaust fluid (DEF) into exhaust streams with the intended goal of nitrous oxide (NOx) emission reduction. In cases where DEF levels ran low or unexpected…
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Best practices for early-season weed control in California rice

May 18, 2026
By Whitney B Brim-Deforest
Reprint from Rice Farming, March 2026Early season weed control is vital to keeping yield potential high in California rice. Most of our yield potential is lost to weed competition in the first 30 days. The vast majority of that yield loss is due to watergrass species (Echinochloa spp.) including…
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Where can you reduce fertilizer input costs?

May 11, 2026
By Bruce A Linquist
This post is somewhat a repeat of last year’s. However, while last year the rice price was low, this year we have both low rice prices and high fertilizer costs. Therefore, there is even more reason to carefully manage your fertilizer input costs. Below are some suggestions on how you can reduce your costs…
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A lot of April rain!

May 1, 2026
By Bruce A Linquist
We have had a lot of rain this past April. I wanted to look at this year relative to previous years. I maintain an on-going database from three CIMIS stations in the Sacramento Valley Rice growing region (Davis, Colusa/Williams and Durham/Biggs). I develop an index where I take the average values from these…
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Remembering Jodie Holt

April 29, 2026
By Justin M Valliere
It is with great sadness that we share the passing of Dr. Jodie Holt, a longtime faculty member in the Department of Botany and Plant Sciences at UC Riverside, who passed away April 27, 2026. Jodie was a leader in weed science whose work helped shape the field at the intersection of ecology and…
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nutria where you can observe its long, rat-like tail

Update on Nutria Populations

April 20, 2026
By Sarah Marsh Janish
Last year during the 2025 Winter Grower Meetings, we mentioned nutria as an emerging invasive pest capable of harming rice fields, especially in the Delta region. After these meetings, we received several anecdotal confirmations of sightings of nutria and nutria burrows around the Stockton area and further…
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Stem Rot Monitoring Guidelines for the Mid Boot Stage

April 13, 2026
By Luis A Espino
Stem rot is a common rice pathogen present in all fields. The pathogen produces resting structures called sclerotia that survive in the soil after harvest. The sclerotia germinate in the spring and the pathogen infects tillers at the water level approximately when plants reach panicle initiation (45 to 50…
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AI generated buff tadpole shrimp weight lifting pesticides

From Highly Effective to Highly Resistant: Pyrethroids and Tadpole Shrimp in Rice

April 6, 2026
By Ian M Grettenberger, Luis A Espino
Additional authors: Sophie Allen, UCD Jr. SpecialistPyrethroids are heavily relied upon for management of tadpole shrimp in California rice. Their efficacy has historically been excellent (and mostly still is!); they have proven both effective and very economical given their low material costs, in particular…
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Weed Management Considerations for Drill-Seeded No-Till Rice

March 30, 2026
By Whitney B Brim-Deforest
Interest in drill-seeded no-till rice has increased in recent years; however, the most comprehensive herbicide research in drill-seeded rice systems was conducted before 2015, more than 10 years ago. Transitioning from water-seeded to drill-seeded rice, whether tilled or no-till, substantially alters weed…
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Statewide Variety Trial Results

March 23, 2026
By Bruce A Linquist
The California Rice Research Board supports our statewide variety trail evaluation each year. This project runs nine variety trails around the state and evaluates commercially available lines as well as promising lines that are coming out of the Rice Experiment Station. These are large trails with each one…
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2025 Year-in Review

March 16, 2026
By Bruce A Linquist
In California, 533,000 acres of rice were planted in 2025, which is the highest amount since 2016. Some of this increase in acreage was seen in San Joaquin County which planted 15,000 acres in 2025. There has been a steady increase in acreage in this county since 2017 when only 3000 acres were planted. …
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Welcome

Participants
NASA Ames Research Center
USDA-ARS Invasive Species and Pollinator Health Research Unit 
California Dept of Parks & Recreation - Division of Boating & Waterways
California Dept of Food & Agriculture
Sacramento-San Joaquin Delta Conservancy
University of California, Davis
Local mosquito vector control districts
 
General areas of study
Weed mapping tools
Management techniques and strategies
Weed effects on ecosystems, native plants, and water quality
Biological control agents
Effects of weeds on mosquito populations
Bio-economic modeling of weed control costs and project benefits

 

Announcements

As of September 2021, a special issue of the Journal of Aquatic Plant Management features participants in DRAAWP. Individual papers can be seen under the "Journal Articles" tab to the left.

We have posted a new 2020 Areawide Report under the Products tab to the left.

This year's Aquatic Plant Management Society annual meeting is planned for July 12-14, 2021, in New Orleans.

The Western Aquatic Plant Management Society (WAPMS) recently participated in a virtual conference jointly with the Western Society of Weed Science. The 40th annual meeting of WAPMS is scheduled for March 7-11, 2022. 

Our DRAAWP informational brochure is available from the Site Navigation tab at the left.

 

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