Yuba County Research Articles

COVID-19 Education and Resource Development for Punjabi-Speaking Sikh Farmworkers in California

ABSTRACT Objective While the vast majority of farmworkers in California are Latinx, a small proportion of the farmworkers are Asian Indian who primarily speak Punjabi. To date, there are few COVID-19 resources developed that specifically target Punjabi-speaking farmworkers. This study examines the COVID-19 educational needs of Punjabi-speaking farmworkers in California and aims to inform future development of educational materials for Punjabi-speaking farmworkers. Methods During early 2021, a two-phase qualitative study was conducted. In Phase 1, five key informant interviews were conducted using a semi-structured interview guide to assess the content, visual, and cultural relevance of current COVID-19 educational resources. Based on informant feedback, new agriculture-specific COVID-19 educational resources were developed in Punjabi. In Phase 2, three focus groups were conducted (in Fresno and Yuba Counties) with five participants in each group to evaluate the newly developed COVID-19 resources. Results Informant interviews showed that Punjabi-speaking farmworkers preferred printed handouts, videos, and radio messages to receive COVID-19 related information. Participants preferred 8–1/2”x11” sized printed handouts that were colorful and had culturally relevant photographs. Participant video preferences included live action videos that were short (1–3 mins) with characters representing the Punjabi community. A substantial majority of focus group participants approved the newly developed COVID-19 educational and safety resources. Conclusion Current COVID-19 resources are not meeting the educational needs of Punjabi-speaking farmworkers. This community needs COVID-19 educational and safety materials that are culturally relevant and linguistically appropriate to be available in different formats: handouts, videos, and radio messages.

The levee effect revisited: Processes and policies enabling development in Yuba County, California

Prolonged, heavy rain in Northern California led to the evacuation of over 180,000 residents on February 12, 2017 after the capacity of the Oroville Dam, which spills into the Feather River, came into question. This paper examines the development of the floodplain along the Yuba and Feather rivers and identifies changes in risk distribution resulting from increased urbanisation. The levee system in this area was extended, and additional embankments were erected between 2004 and 2011. Olivehurst has particularly experienced high population growth and increased housing values despite a history of flooding, partly due to failed mitigation structures. Increased development stemming from a false sense of security associated with mitigation projects, termed the levee effect, has been well documented. Analyses of census data, land cover change, Federal Emergency Management Agency (FEMA) flood zone designations, and county development plans indicate that several factors other than available land have precipitated expansion: (a) population pressure, (b) recertification of the levees that now confine the official floodplain, and (c) the fact that flood insurance is no longer a requirement for homeowners. Development trends from 1980 to 2015 put communities built in anticipation of the upgraded levee system that are completely reliant upon it for flood protection at risk.

Exploring scientific information for policy making under deep uncertainty

Each actor evaluating potential management strategies brings her/his own distinct set of objectives to a complex decision space of system uncertainties. The diversity of these objectives and uncertainties requires detailed and rigorous analyses that respond to multifaceted challenges. The utility of this information depends on the accessibility of scientific information to decision makers. This paper demonstrates data visualization tools for presenting scientific results to decision makers in two case studies, La Paz/El Alto, Bolivia, and Yuba County, California. Visualization output from the case studies combines spatiotemporal, multivariate and multirun/multiscenario information to produce information corresponding to the objectives and uncertainties described by key actors. These tools can manage complex data and distill scientific information into accessible formats. Using the visualizations, scientists and decision makers can navigate the decision space and potential objective trade-offs to facilitate discussion and consensus building. These efforts can help identify stable negotiated agreements between different stakeholders.

Interactions among habitat, management, and demography for an invasive annual grass

Effective long-term management of noxious plant species depends on our ability to identify and manage ecological processes-driving invasion and to use site-specific information to design realistic management strategies and goals. However, there is a surprising lack of research that investigates relationships among habitat characteristics, weed demography, and management efforts. We investigated the interactions among these factors using the invasive annual grass medusahead (Elymus caput-medusae). In Yuba County, California, we seeded medusahead in densities from 0 to 50,000 seeds/m2 in open grassland and oak woodland habitats. We also exposed plots to defoliation none, once, or twice in a season and captured how medusahead germination, establishment, and persistence responded to experimental treatments. We found that medusahead establishment was higher in the grassland, compared to the woodland habitat, likely due, in part, to the presence of litter under oak canopies. After a single defoliation event, medusahead persistence was higher in the oak, but not the grassland plots. We also found that defoliation once or twice reduced medusahead density. However, a single clipping treatment actually resulted in increased seed production. This was likely a compensatory response by a younger cohort, and provides an explanation for why single control efforts do not generally result in successful long-term outcomes. This work highlights the complex relationships between density-dependent and density-independent processes that may influence invasion dynamics.

UC Cooperative Extension works with fire safe councils to reduce wildfires

In Plumas, Butte and Yuba counties, UC Cooperative Extension advisors have collaborated with fire safe councils to mitigate the risk of wildfire in local communities. They have determined the educational needs within the communities, obtained grant funding and worked collaboratively with the councils to deliver education and applied research programs that have helped homeowners and landowners take action to reduce their vulnerability to the risk of wildfires. Home structures have been modified to improve their fire resistance, fuel reduction programs have been adopted by local communities and maintained, communities have been mapped for evacuation plans and fuel breaks have been constructed on private and public forestland. Several wildfires, including the Marysville fire in 2006 and the Yuba fire in 2009, were slowed or stopped because of measures taken, showing the value of investment in pre-fire planning and actions.

FIRST REPORT OF LASIODIPLODIA CITRICOLA ASSOCIATED WITH STEM CANKER OF PEACH IN CALIFORNIA, USA

In July 2009 and October 2012, stems of young peach (Prunus persica) trees with cankers from Kings, Fresno and Yuba Counties, respectively, in California were submitted to our diagnostic laboratory. The cankered areas were discoloured brown in comparison with the creamy healthy bark and covered with gum galls. More than 30 trees were killed in Fresno and Kings Counties, and 6 trees in Yuba County. Scraping the cankers revealed large black pycnidia and brown discoloured wood. A fungus consistently isolated from the cankers was identified as Lasiodiplodia citricola based on morphological characteristics (Abdollahzadeh et al., 2010) and analyses of ITS, and TEF-1α gene regions. The sequence showed high identity (ITS, 100%; TEF-1α, 99%) with reference sequence (isolate: IRAN 1522C = CBS 124707, ex-type of L. citricola; accession Nos.: ITS, GU945354; TEF-1α, GU945340; β- tubulin, not available) for L. citricola (Abdollahzadeh et al., 2010). Sequences were deposited to GenBank (isolates: 7F93, 7F94 and 7F95. Accession Nos.: ITS, KC357262–KC357264; TEF-1α, KC357268–KC357270; β-tubulin, KC357265–KC357267). Pathogenicity of L. citricola in P. persica variety nectarina cv. Summer Fire was tested using three isolates. Ten two-year-old branches for each isolate were inoculated. Inoculations were made in late Oct. 2012 as described by Chen et al. (2013). Lesion length was measured 3 weeks after inoculation. The three isolates of L. citricola produced 60–67-long lesions within 3 weeks, while wounds were covered with callus tissue in the control inoculations. L .citricola was reisolated from the inoculated branches and no fungus was re-isolated from the control branches. These results indicate the pathogenicity of L. citricola to P. persica.

Distribution and phenology of Rhagoletis fausta (Osten Sacken 1877) and Rhagoletis indifferens Curren 1932 (Diptera: Tephritidae) in California

Abstract We determined the distribution of Rhagoletis fausta (Osten Sacken 1877) and Rhagoletis indifferens Curren 1932 (Diptera: Tephritidae) in California outside the state interior quarantine area. Our data confirmed the historical records of R. fausta in Alpine, Amador, El Dorado, Fresno, Kern, Mariposa, Mendocino, Modoc, Mono, Nevada, Placer, Plumas, Sierra, Tehama, Tulare, and Tuolumne counties and we trapped R. fausta for the first time in Butte, Calavaras, Glenn, Inyo, Lassen, Madera, and Yuba counties. We confirmed the historical records of R. indifferens in Amador, El Dorado, Fresno, Mendocino, Modoc, Nevada, Placer, Plumas, and Sierra counties and we trapped R. indifferens for the first time in Butte, Calaveras, Lassen, Madera, Mariposa, Tulare, Tuolumne, and Yuba counties. No R. fausta were trapped in Lake, Los Angeles, or San Bernardino counties and no R. indifferens were trapped in Alpine, Glenn, Inyo, Lake, Mono, or Tehama counties. The lower altitude at which we trapped both flies increase...

A New Sidalcea (Malvaceae) from Northeastern California

Sidalcea gigantea G. Clifton, R. E. Buck, & S. R. Hill is described as a new species from the northwestern slope of the Sierra Nevada in Butte, Plumas, Sierra, and Yuba Counties and from the extreme southern Cascade Range in Shasta County, California. The new species is a robust, long-lived perennial from large and extensive rhizomes; it is one of the tallest species known in the genus and it forms the largest known clonal colonies. Based on both morphological and DNA characters, S. gigantea appears to be most closely related to S. asprella Greene and S. celata (Jeps.) S. R. Hill, both found in the vicinity of the new species. Sidalcea gigantea occurs around margins of meadows, seeps, and streams in montane conifer forests, especially Mixed Conifer Forest.

Distribution of California Black Rails in the Sierra Nevada foothills

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Livin’ Large with Levees: Lessons Learned and Lost

The use of levees for flood control has a long history in the United States in part because their relatively low construction costs and general effectiveness in protecting low-lying areas are politically expedient. Consequently, there are thousands of counties and communities relying on levees as their primary flood protection measure. However, levees can also promote floodplain development, placing more property at risk, and they have negative hydrological and environmental consequences. In addition, failures occur when design standards are exceeded or because of poor maintenance, leading to catastrophic losses. Recognizing these limitations, the Association of State Floodplain Managers has issued 25 recommendations regarding the use of levees, three of which are evaluated here in the context of Yuba County, California, a county that has experienced three major flood events in the last 25 years due to levee breaks. Faced with ongoing development pressures and suburban sprawl from Sacramento, Yuba County has permitted several new residential areas in the flood-prone land, in anticipation of levee certification. The county's levee strategy demonstrates the county is going beyond what is currently required for official certification of its levees. However, it is clear that additional measures need to be taken in order for the risk to be fully acknowledged and managed.

Mining pesticide use data to identify best management practices

AbstractThis paper reports on the initial findings of an ongoing research project to capture differences in pest management strategies and decision-making among growers using the California Pesticide Use Reports (PUR) database. Analysis was performed for prunes in Sutter and Yuba counties to identify on-farm innovation by analyzing the PUR for best management practices to reduce pesticide use. Results showed that large variations in pesticide use were present in 2000, with a range of less than 5 kg to more than 41 kg of pesticide applied per hectare (ha) crop planted in Sutter County and a range of less than 2 kg to close to 30 kg per ha crop planted in Yuba County. Among the 42 growers selected cultivating more than 80 ha, five growers in Sutter County and three growers in Yuba County in 2000 were identified as low pesticide use growers. The results indicated a surprising number of low to no fungicide users and an even higher number of growers using no herbicides in both counties. Twenty-nine viable low pesticide use growers were identified overall among the total 294 growers in the Sutter and Yuba counties. However, there were no spatial patterns of where these low pesticide use growers' fields were located. The transition from higher-risk active ingredients (AIs) to reduced-risk AIs used by many of the low pesticide users suggests intentional substitution. Initial yield data indicate that quantity and quality were not adversely affected by low use growers employing reduced-risk pesticides, fewer (AIs) per field, and lower rates per chemical than their moderate to high use counterparts. Diverse collaborators consisting of university researchers, environmental and community organizations, state government scientists, and growers worked together throughout the entire project, beginning with defining the research parameters, then interpreting the results, and finally suggesting practical applications for the outcomes. The paper also highlights the effectiveness of using such collaborative research relationships to explore low pesticide use alternatives, to directly exchange research findings with growers, and to encourage a farmer-to-farmer extension model.

GENETIC RELATIONSHIPS AMONG FREMONTODENDRON (STERCULIACEAE) POPULATIONS OF THE CENTRAL SIERRA NEVADA FOOTHILLS OF CALIFORNIA

ABSTRACT Fremontias, or flannel bushes (Fremontodendron), are a distinctive element of California's chaparral communities. Fremontodendron decumbens is only known from a few populations in gabbro soil plant communities of the Sierra Nevada foothills in El Dorado County. Although a recovery plan for these communities has been drafted, the long-term management of F. decumbens is complicated by its treatment as a subspecies of the more widespread F. californicum, and by the recent discovery of additional populations of decumbent plants in Yuba and Nevada Counties that are not easily assigned to either F. californicum or F. decumbens. Genetic relationships among 5 populations, including F. californicum, F. decumbens, and the decumbent plants in Yuba County, were ascertained using AFLP markers. Principal coordinates and population structure analyses of the AFLP data showed that F. decumbens is genetically distinguishable from the populations of F. californicum that we sampled. This distinction, coupled with it...

Integrating prescribed burning and clopyralid for the management of yellow starthistle (Centaurea solstitialis)

Prescribed burning and the herbicide clopyralid are very effective tools for the management of yellow starthistle. However, repeated use of either can be impractical or can present other problems. The potential solution is the development of an effective integrated weed management strategy using a combination of the two approaches. In small plot studies (0.2 ha), we tested one of five possible treatments: (1) untreated control, (2) 2 consecutive yr of clopyralid (0.105 kg ha−1), (3) 2 consecutive yr of prescribed summer burning, (4) first-year clopyralid followed by second-year prescribed burning, and (5) first-year prescribed burning followed by second-year clopyralid. Treatments were made in 1999 and 2000 at three study sites in California (San Benito, Yuba, and Siskiyou counties). In 2001, the year following the final treatment, 2 consecutive yr of clopyralid or first-year burning followed by second-year clopyralid consistently reduced yellow starthistle cover in the following year by 92 to 100%. However, at the Yuba site, clopyralid alone increased medusahead and ripgut brome cover. Although 2 consecutive yr of burning was effective in Yuba, very high levels of starthistle infestation in San Benito were not completely burned in the second year because of the lack of available consumable fuel. Clopyralid treatment the first year followed by prescribed burning in the second year stimulated yellow starthistle germination and did not reduce the infestation. In a large-scale study conducted at two sites (13 and 81 ha) in southern Monterey County, we used a first-year burn followed by either 2 yr of clopyralid (0.158 kg ha−1) or a single year of clopyralid (0.210 kg ha−1) and a subsequent burn. Results were in close agreement with those found in the small-scale studies. In the year following the final treatment, control of yellow starthistle was greater than 99% when the burn was followed by 2 yr of clopyralid. In contrast, when a prescribed burn was used in the last year of the program, the level of control was not as good, probably because of the increased germination of the remaining soil seedbank. These results indicate that a first-year prescribed burn followed by a second-year clopyralid treatment can provide consistently good control of yellow starthistle, as well as reduced levels of noxious annual grasses, including medusahead and ripgut brome.

A GENETIC AND MORPHOLOGICAL STUDY OF CLARKIA STELLATA (ONAGRACEAE) AND RELATED SPECIES IN NORTHEASTERN CALIFORNIA

ABSTRACT Clarkia stellata Mosquin (Onagraceae) is an uncommon annual herb endemic to Plumas and Yuba Counties in northeastern California that has threatened populations due to noxious weeds, recreational and forest management activities, and development. The purpose of this study is clarify the species identification of populations of Clarkia stellata for management purposes, specifically, populations of C. stellata and C. rhomboidea that are difficult to differentiate in the field. A total of 11 populations of C. stellata and related species were sampled for morphometric analyses and nine populations were sampled for genetic analysis using amplified fragment length polymorphisms (AFLPs). Clarkia stellata can be separated from C. rhomboidea based on all floral characteristics except claw width, claw length, and isthmus width. These species also can be differentiated based on the following vegetative characteristics: petiole length, leaf length, leaf width, and plant height. The sympatric Clarkia mildredia...

Mapping the risk of establishment and spread of sudden oak death in California

Sudden oak death, caused by the recently described pathogen Phytophthora ramorum, is an emerging forest disease that has reached epidemic levels in coastal forests of central California. We present a rule-based model of P. ramorum establishment and spread risk in California plant communities. The model, which is being used as a management tool to target threatened forests for early-detection monitoring and protection, incorporates the effects of spatial and temporal variability of multiple variables on pathogen persistence. Model predictions are based on current knowledge of host susceptibility, pathogen reproduction, and pathogen transmission with particular regard to host species distribution and climate suitability. Maps of host species distributions and monthly weather conditions were spatially analyzed in a GIS and parameterized to encode the magnitude and direction of each variable's effect on disease establishment and spread. Spread risk predictions were computed for each month of the pathogen's general reproductive season and averaged to generate a cumulative risk map (Fig. 6a and b). The model identifies an alarming number of uninfected forest ecosystems in California at considerable risk of infection by Phytophthora ramorum. This includes, in particular, a broad band of high risk north of Sonoma County to the Oregon border, a narrow band of high risk south of central Monterey County south to central San Luis Obispo County, and scattered areas of moderate and high risk in the Sierra Nevada foothills in Butte and Yuba counties. Model performance was evaluated by comparing spread risk predictions to field observations of disease presence and absence. Model predictions of spread risk were consistent with disease severity observed in the field, with modeled risk significantly higher at currently infested locations than at uninfested locations ( P < 0.01, n = 323). Based on what is known about the ecology and epidemiology of sudden oak death, this model provides a simple and effective management tool for identifying emergent infections before they become established.

Human and Pet-related Risk Factors for Household Evacuation Failure During a Natural Disaster

This study characterized risk factors for household evacuation failure. A random digit dial telephone survey was conducted of 397 households in Yuba County, California, in July 1997, 6 months after residents had been under evacuation notice due to flooding. Case households failed to evacuate, whereas control households evacuated. The cumulative incidence of household evacuation failure was 19.4%. Fewer households with children (25.8%) failed to evacuate than households without children (45.9%, p < 0.01). More households with pets (20.9%) than households without pets failed to evacuate (16.3%, p = 0.11). With multivariate logistic regression, the risk of household evacuation failure was lower in households with children (odds ratio = 0.4, 95% confidence interval: 0.2, 0.8) compared with households without children. The risk of household evacuation failure increased in pet-owning households without children (odds ratio = 1.3, 95% confidence interval: 1.1, 1.5) compared with pet-owning households with children; the more pets a household owned, the higher the risk of household evacuation failure was. Impediments to pet evacuation, including owning multiple pets, owning outdoor dogs, or not having a cat carrier, explained why many households that owned pets failed to evacuate. Predisaster planning should place a high priority on facilitating pet evacuation through predisaster education of pet owners and emergency management personnel.

A Study of Pet Rescue in Two Disasters

Pet rescues endanger public and animal health in disasters and are a direct consequence of pet evacuation failure. This study characterized pet rescue attempts in two disasters. A random digit dial telephone survey was conducted of 397 households in Yuba County, California, where residents were under an evacuation notice due to flooding. A mail survey was conducted of 241 households in Weyauwega, Wisconsin, where residents evacuated from a hazardous chemical spill. Risk factors for pet rescue were identified using multivariate logistic regression. Case households were defined as those that evacuated without pets and later attempted to rescue them, while control households were those that evacuated without their pet and did not attempt a rescue. Approximately 20 percent and 50 percent of pet-owning households that evacuated failed to take their pet with them in Yuba County and Weyauwega, respectively. Approximately 80 percent of persons who reentered the evacuated area did so to rescue their pet. Attempts to rescue a pet was most common by households with children. Predisaster planning should, therefore, place a higher priority on facilitating pet evacuation so as to minimize the subsequent need to rescue pets.

The Barred Owl (Strix varia) Invasion in California

We estimated the range expansion of Barred Owls (Strix varia) in California and the potential negative effects this species may have on Spotted Owls (Strix occidentalis). Barred Owl range expansion has been rapid over the past two decades. A total of 61 Barred Owls has been detected in 12 different California counties. Barred Owls were first sighted in California in 1981 in Del Norte and Trinity counties. They now have been detected as far south as Sonoma County in western California and Yuba County in the Sierra Nevada. The ratio of new Barred Owl sites found per new Spotted Owl territory has increased from one per 50 Spotted Owl territories in the 1980s to one per 10 to 20 new Spotted Owl territories in the mid 1990s. This suggests that the Barred Owl population in California is increasing. In addition, seven Barred Owl X Spotted Owl hybrids have been reported in California. Because of the potential for hybridization, competition for food and habitat, and predation, it appears that the Barred Owl could influence Spotted Owl populations negatively. Received 12 December 1996, accepted 19 May 1997.

Postharvest prune rust does not lower French prune yield

Yields and fruit quality of French prune trees in Tulare and Yuba counties were not improved by controlling late-season prune rust with mancozeb or sulfur over a 3-year period. Accelerated postharvest leaf loss induced by disease did not appear to cause a decline in yields in the following year. In a comparison of mancozeb 80W and sulfur 92W for control of prune rust, mancozeb provided superior control.

Lack of Effect of Stone Fruit Rust on Yield of French Prune Trees and Survival of Urediniospores of the Pathogen on Leaves, Shoots, and Buds

Two prune (Prunus domestica «French» orchards, one in Tulare County and one in Yuba County, California, were treated either two or three times in summer with mancozeb or sulfur or left untreated for 3 yr. Fresh and dry fruit weights per tree, number of dry prunes per kilogram, fresh to dry weight ratio, and percent soluble solids were determined each year. Significant differences in yield parameters were few, minor, and inconsistent. Preharvest defoliation did not occur in either orchard in any year, but postharvest leaf loss was faster and leaf infection greater in control and sulfur than in mancozeb treatments. The number of urediniospores on buds declined from November through February, and the number on 1- and 2-yr-old shoots declined from November through April