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Thoughts on Rice
This podcast is for growers, PCAs, consultants, and other industry professionals in the California rice industry. We'll primarily be focusing on the Sacramento Valley and Delta Region of California. The UCCE Rice Farm Advisors aim to deliver extension information relating to the California rice industry.
Find out more about UCCE and California rice here!
Thoughts on Rice
Nutria as emerging pests
In honor of National Invasive Species Awareness Week, Sarah Marsh Janish discusses the recent focus on nutria in California. Although this semi-aquatic mammal is not new to California, the surge in population and range across the state is of some concern, especially to those of us who work in the habitats they prefer to inhabit.
Report Nutria: "Suspected observations or potential signs of nutria in California should be photographed and immediately reported to CDFW ONLINE, by email to Invasives@wildlife.ca.gov, or by calling (866) 440-9530."
Nutria Links
UCCE Annual Meeting - Emerging Pest Presentation
Upcoming Events!
Propanil Stewardship Meetings
March 17 in Woodland at the Yolo County Farm Bureau office
March 18 in Richvale at the Community Church.
Other Resources
UC Rice Blog
UC ANR is an equal opportunity provider and employer
Hello and welcome to Thoughts on Rice, a podcast hosted by the University of California Cooperative Extension Rice Advisors. I'm one of your hosts, Sarah Marchionish, and I'm a rice farm advisor for Colusa and Yolo counties.
SPEAKER_00:I'm Whitney from DeForest. I'm the Cooperative Extension Rice Advisor for Sutter, Yuba, Placer, and Sacramento counties.
SPEAKER_01:My name is Luis Espino. I'm the Rice Farming Systems Advisor for Butte and Glynn counties.
SPEAKER_02:I'm Michelle
SPEAKER_01:Leinfelder-Miles.
SPEAKER_02:I'm a farm advisor in the Delta region. I work on all sorts of field crops, grains and forages, but one of those is rice. And the counties that I cover are San Joaquin, Sacramento, Yolo-Solano, and Contra Costa counties.
SPEAKER_03:Together, the UCC rice farm advisors seek to provide relevant, topical, research-backed information relating to California rice production. Forgive me if I sound a bit off today. We just got back from the Rice Technical Working Group conference in New Orleans last week, and I have been fighting off the cold that everybody seemed to have. Disregarding that, it was a fantastic conference, with a lot of great talks from all over the US and the globe, and I can't wait to go to the next one in Texas in 2027. Today, in honor of Invasive Species Week, I'll be discussing the recent focus on Nutria in California. Although this semi-aquatic mammal is not new to California, the search Urge and population and range across the state is of some concern, especially to those of us who work in the habitats they prefer to inhabit. This talk is paraphrased from one that I gave during the annual UCCE grower meetings earlier this month, so if it sounds a bit familiar, that's why. Music Nutria, or koipu if that's a name you're more familiar with, are large semi-aquatic rodents that are native to South America. The species is invasive in the U.S. and currently established in 17 states, including California. Nutria inhabit both freshwater and brackish coastal water areas and can be found near permanent water sources, including rivers, streams, lakes, ponds, wetlands, and continual rice production. However, they can still thrive in urban conditions. In cities, they can be found in their buildings, in overgrown lots, on golf courses, and in storm drains. Nutria thrive in warmer conditions, such as the southeastern region of the U.S., and their reproductive success is reduced by severe winter conditions. However, that's not to say they're not found in the north. They are there. They just have a little bit less success in terms of reproduction. They can grow in size up to 20 pounds and have partially webbed feet. Often mistaken for small beaver or very large muskrats, Nutria can be differentiated by large front teeth that are yellow to orange in color, a heavy, rat-like tail, and prominent white whiskers that protrude from either side of their nose. Incidentally, Nutria have actually been present in California for over a century. Introduced in 1899 to stoke the fur trade, the first members of the species were spectacularly unsuccessful, and the species was declared eradicated from California in the 1970s. This remained true until the spring of 2017, when the California Department of Fish and Wildlife, or CDFW, trapped and necropsied a pregnant female nutria in Merced County. This action triggered monitoring and eradication efforts across the state, which have indicated that nutria is spreading further north every year. Nutria are known for their herbivory and burrowing behavior, which we'll go further into detail about, but they also serve as hosts for tuberculosis and septicemia, which are threats to humans, livestock, and pets. Additionally, nutria carry tapeworms, a nematode that causes a rash known as nutria itch, and blood and liver flukes, which can contaminate swimming areas and drinking water supplies. Nutria can consume up to 25% of their body in above and below ground plant tissue, but they can waste and destroy up to 10 times as much. They clip the plant stems at the waterline and can denude entire landscapes with relatively small populations, causing extensive damage to the native plant community and soil structure, as well as significant losses to nearby agricultural crops. Nutria do not make dens, but rather burrow into levees, riverbanks, or other water control structures, frequently causing water retention or flood control levees to breach, weakening structural foundations, and eroding banks. Thanks. Their burrows have entrances at the waterline for easy access from the water. Additionally, nutria can be problematic in the ways that they increase their populations, because this species is excellent at population growth. Nutria are such prolific breeders that one female can lead to 200 offspring in just a year. In a population modeling experiment from Oregon State University, a hypothetical nutria population was mapped, assuming two litters per year and a 20% predation or loss rate. One breeding pair, after five years, resulted in 2,048 nutria. Part of the reason of this exponential population growth is because nutria reach sexual maturity at about four to six months. Females have anywhere from five to seven babies in a litter, and they can have several litters every year. Additionally, nutria have a high rate of migration and can The current geographic distribution of nutria in California concerns those of us involved in rice production. Current maps from the CDFW place nutria hotspots in the Delta, near rice production areas. However, maps also show that nutria is being spotted as far north as Fairfield, which starts encroaching on the Sacramento Valley rice production areas. As the preferred habitat of these rodents is identical to that of a rice field, the potential for damages is high. Additionally, identifying the rice damage caused specifically by nutria can be challenging, as it is easy to confuse it with the damage caused by muskrats, as both rodents clip the stems of the rice plants at the waterline. At high densities, nutria can substantially impact plant communities. In the U.S., rice is one of the prime However, nutria also favor crops and plants that can neighbor rice fields, including corn, grain sorghum, alfalfa, wheat, barley, oats, melons, and a variety of vegetables from home gardens and farms. When it comes to current methods to try and control the spread of nutria in California, CDFW is collaborating with other agencies and local partners to develop the most effective strategy for eradicating nutria from California. CDFW believes that the current state of nutria population in California indicates that eradication is possible if rapid response is taken. This is really good news, especially compared to other states where eradication is no longer a feasible goal, but instead population control is the attempt. As an example, the nutria population in Louisiana, where the population control costs up to$2 million per year for bounty harvest alone, is an indication where eradication is not an option. In California, nutria are classified as a non-game animal. Fish and Game Code 4152 specifies that property owners or their agents who possess written permission from the owner or tenant may take nutria at any time by any legal means to address damage to crops or property. Restrictions apply to the use of traps and the types of traps, but this does indicate a terminal take, because nutria are a restricted species in California under the California Code of Regulations, Title 14, Sections and cannot be imported, transported, or possessed live in the state of California. In other states, bounty programs are underway to encourage the taking of nutria. However, in California, it is illegal to offer a bounty for nutria. California Fish and Game Code Section 2019 clearly states, it is unlawful for any person, including state, federal, county, and city officials or their agents, to authorize, offer, or or pay a bounty for any bird or mammal. State legislation changes would have to take place to alter the code to provide an exemption for nutria. Any nutria taken on private or public land should be reported to CDFW as soon as possible for purposes of delineating the extent of the infestation. At minimum, CDFW needs photos to confirm identification. Preferably, CDFW needs the carcass to determine sex, age, and reproductive status. Suspected observations or potential signs of nutrient California should be photographed and immediately reported to CDFW online, by email to invasivesatwildlife.ca.gov, or by calling 866-440-9530, and we'll have that information linked in the show notes. Observations on state or federal lands should be immediately reported to local agency staff. If this species is captured, do not release it. Immediately contact your local CDFW office or county ag commissioner. Finally, to wrap up, I'm reaching out to you, our listeners. If you live in California and you think you've seen a nutria, let us know. We're hoping to raise awareness of this invasive pest in the state. Feel free to reach out through any of the contact methods I'm going to mention shortly. We have a few upcoming events. The UCCE Rice team will be holding a propanil stewardship meeting. And this will take place in two locations on two different dates, but it'll be the same meeting. And the first will be March 17th in Woodland at the Yolo County Farm Bureau office. And the second date will be March 18th in Richvale at the Community Church. We'll have the agenda and all other information up on our resources, but that is still to be announced. So for more information about these and other upcoming events, feel free to check out our resources, which include the UC Rice blog and the UC Agronomy Rice website. In terms of other resources you may want to take advantage of, you can also look at our Thanks for listening to Thoughts on Rice, a University of California Cooperative Extension podcast from the University of California Agriculture and Natural Resources. You can find out more about this podcast on our website, thoughtsonrice.buzzsprout.com. We'd love to hear from you, whether it's from using our text link in the show notes, a survey submission in our feedback form, also in the show notes, or in a comment or rating on your podcast streaming service of choice. We're also experimenting with polls on Spotify, so if you're listening on Spotify, you may have an option to answer some of those questions, and we might be able to talk about that on air. You can also email us with any comments, questions, or concerns at thoughtsonrice at ucdavis.edu. Spring has sprung for those of us here in the Sac Valley, and rice season is right around the corner. Remember, like the growers like to say, Have a rice life. Mention of an agrochemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label. The label is the law. Find out more at ipm.ucanr.edu. The views, thoughts, and opinions expressed are the speaker's own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented herein Thank you.
