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A major collaborative project launched in 2017 to accelerate the development of disease-resistant strawberry cultivars is responding urgently to two developments: increasing restrictions on fumigant use and the appearance of two novel pathogens not evidently manageable with allowed fumigants. As part of that project, I sought to understand the factors that guide growers' cultivar choice and assess their willingness to choose a pathogen-resistant cultivar to reduce or potentially replace fumigation. From a survey completed by 33 strawberry growers and in-depth interviews with 20 growers, I found that most growers prioritize yield in choosing cultivars, despite the industrywide problem with low prices. Few growers said they would be willing to substitute disease-resistant cultivars for fumigation without fail-safe disease control methods. Many growers, even those with existing organic programs, would opt for soilless systems in a tighter regulatory environment. This study thus suggests that disease resistance breeding must be coupled with support for other disease management techniques, and the economic situation that makes growers feel that they cannot forgo yield also needs attention.

Several ways to address the looming ecological disaster that is the Salton Sea have been proposed — including water importation. Here we considered two options: importing ocean water from the Sea of Cortés and leasing water from agricultural users in the Imperial Valley. We estimated the monetary costs for importing Sea of Cortés water to the Salton Sea and compared that with the costs of transferring water from agricultural users to the Salton Sea. We found that leasing water from agriculture would be substantially cheaper than ocean water imports. Additionally, all the infrastructure for leasing water from growers exists, which means water transfers could begin immediately. That is important given the present and increasing environmental and human health damages that are occurring at the Salton Sea.

Traditional sources of retail price information, such as scanner data and government price surveys, are not available for cannabis. To help fill this gap, between October 2016 and July 2018 the UC Agricultural Issues Center collected online retail price ranges for dried cannabis flower and cannabis-oil cartridges at retailers around California. During this 21-month time period, the legal landscape of the California cannabis market underwent three broad regulatory changes: adult-use decriminalization, licensing and regulation and mandatory testing. This article provides unique primary data on legal cannabis prices in California before and after each of these three changes. Our data are imperfect but do provide a glimpse of the patterns of California cannabis prices at different times. For dried cannabis flower, we observe relatively stable retail prices over the 21-month period at both the top and bottom ends of the price range. For cannabis-oil cartridges, we observe relatively stable prices at the bottom end but increasing prices at the top end between November 2017 and July 2018.

In 2018, we surveyed cannabis growers about their experiences with California's commercial cultivation legalization system. Our results suggest high rates of noncompliance with the new regulations. Of the respondents, 31% reported income from cannabis and had not applied for cultivation licenses, indicating a violation of state regulations. These findings highlight the need to further explore conditions that might incentivize growers to apply for cultivation licenses. Respondents' answers and comments indicate modifications to cannabis cultivation licensing programs might be needed to reduce compliance costs and regulatory inconsistencies and to overcome threats of legal repercussions from enhanced bureaucratic oversight. Growers characterized legalization as a process that excludes small growers, contributes to an increase in black market sales and undermines the economies in rural communities. More research is necessary, including on the socioeconomic and environmental contributions that unlicensed small cannabis growers make to rural regions.

Pierce’s disease of grapevines, caused by a strain of the bacteria Xylella fastidiosa, threatens an industry with a farm value of production exceeding $3 billion per year. The grape industry incurs substantial costs from losses of vines to the disease and efforts to mitigate damage. Additional costs are borne by the public in providing programs that aim to contain the disease and develop longer-term solutions, and by the citrus, nursery and grape industries in complying with those programs. Aggregating the costs of vine losses, industry assessments, compliance costs, and expenditures by government entities, we estimate the cost of Pierce’s disease in California is approximately $104.4 million per year. Of that, $48.3 million funds Pierce’s disease activities undertaken by various government agencies, the nursery and citrus industries and the UC system, and $56.1 million is the cost of lost production and vine replacement borne by grape growers.

More than 40 million hundredweights of rice are produced in California's Sacramento Valley every year. After harvest, the rice is stored in facilities on-farm or off-farm until it is transported to mills or to ports for export. We conducted a survey of storage operations to characterize grain storage and pest management practices to guide future UC Cooperative Extension research efforts. The results indicate that grain moisture content, temperature and insect pest management are the most important challenges for both on- and off-farm storage operations. Survey responses show high adoption of integrated pest management programs, with most storage operations relying on monitoring, thresholds, sanitation and aeration to manage pest problems. Fumigant use was reported more frequently in off-farm storage operations than on-farm operations. Cooperative Extension educational efforts should focus on grain and temperature monitoring, insect identification and safe use of fumigants. Research is needed to improve management of grain temperature and moisture content, and insect infestations.

In the late 1990s, widespread outbreaks of Pierce's disease in grapevines were linked to transmission via the glassy-winged sharpshooter (GWSS), threatening California's multibillion-dollar table, raisin and wine grape industries. Government agencies responded to the crisis by implementing two control programs to manage GWSS. We analyzed the long-term economic impact of these two programs on citrus, grape and nursery producers. The net economic effects on all citrus producers and on grape producers in the southern San Joaquin Valley were insignificant, while all grape producers in the Temecula Valley saw an average increase in annual production costs of about $13.04 an acre. Based on our survey of nurseries in Southern California, approximately 11% had an infestation in 2008 and 2009, but only 3.0% in 2010. Average losses to nurseries per GWSS infestation were about $12,238. Nursery producers also undertook a variety of pest control methods to prevent infestations and plant losses, and to meet quarantine regulations. Average annual per-acre costs of these approaches were $2,975 for barrier methods to prevent GWSS from entering a premises, $1,032 in pesticide controls and $1,588 for in-house monitoring.

Community Supported Agriculture operations (CSAs) have grown rapidly in recent years. The original model, in which members support a farming operation by paying for produce in advance and receive a share of the farm's produce in return, has been adapted, with much innovation. Since little research existed on CSAs in the Central Valley, we surveyed and carried out in-depth interviews with 54 CSA farmers and two CSA organizers in the Central Valley and surrounding foothills. Here we focus on four aspects of these CSA operations: type, economic viability, farmer characteristics and farm attributes. We found two main CSA models, box and membership/share. Fifty-four percent of the CSAs reported being profitable, and the average gross sales per acre were $9,084. CSA farmers are diverse in political orientation, yet are generally younger, better educated and more likely to be women than the general farming population. CSA farms are relatively small, with a median size of 20 acres; have a median membership of 60 (585 average); use agroecological methods; cultivate agrobiodiversity; and utilize growing practices that generally meet or exceed National Organic Program standards.

Growing evidence of agricultural water pollution in California's Central Coast even after the implementation of tough water quality regulations has increased the pressure on regional stakeholders. Previous research has shown that collaborative relationships between growers and regulators can motivate growers to make management decisions that benefit the environment. However, informal evidence suggested trust might have been eroding between growers and the Central Coast Regional Water Quality Control Board (CCRWQCB, the regulator) since 2004, the year the first legislation went into effect. Using a survey conducted in 2015, interviews and in-depth document review, this study assesses growers' trust of and communication with other agricultural groups and water quality regulatory agencies, specifically CCRWQCB. Survey results were compared to results of the same survey sent out in 2006. Results corroborate other research — growers' trust of most regional agricultural groups was closely correlated with frequency of communication. However, growers' trust of CCRWQCB did not correspond to the relatively high contact frequency and had declined since 2006. The literature on rebuilding trust suggests ways forward for CCRWQCB.

The fresh market berry industry in Santa Cruz and Monterey counties has contributed significantly to the agricultural vibrancy of the two counties and the state of California. Dramatic growth in strawberry, raspberry and blackberry production has been documented over the last 50 years, and most notably since the 1980s. Factors influencing this growth include innovations in agricultural practices and heightened consumer demand. Here, we review the historical context for the berry industry in Santa Cruz and Monterey counties. Organic production, production economics and challenges for the future are also discussed.

The spotted wing drosophila, first detected in California in 2008, has become a major insect pest in caneberries and sweet cherries, causing commercial crop losses. Managing it is challenging because it has many other hosts, including riparian and backyard fruit plantings, and it increases rapidly, with generations overlapping one another. In our study we monitored trap captures in two parts of the San Joaquin Valley, within sweet cherry orchards and in nearby locations. Captures of adult flies showed two main periods of activity — spring and fall — and low captures in the winter (except for citrus and evergreen riparian areas) and summer. On many occasions during the year, trap captures were higher outside of the cherry orchards than within them. Additionally, early in the season, when decisions about control programs are being made, the sex ratio of captured flies in cherries was strongly female-biased. The results suggest that during the weeks leading up to harvest growers should experiment by placing traps in different environments surrounding their orchards to determine SWD activity and potential pest pressure locally, and monitor for both male and female flies.

The impacts of climate change on agriculture depend on local conditions and crops grown. For instance, warmer winter temperatures in a given area would reduce chill hours, potentially cutting yields for some crops but extending the growing season for others. Using a century of climate data and six decades of acreage data, we established quantitative economic relationships between the evolution of local climate and acreage of 12 important crops in Yolo County. We then used the historical trend in climate change to project future crop acreages in the county. Only marginal changes in acreage in 2050 were projected for tree and vine crops there, in part because chill hours, although lower, remained above critical values. Walnuts were the most vulnerable tree crop, and the projections indicated some cultivars might be marginal in years with particularly warm winters. Processing tomato acreage might increase, due to a longer growing season, and also alfalfa acreage, if water availability and other factors remain constant.