Postharvest losses from temperature during transit: Evidence from a million truckloads

Options for managing southern blight of processing tomato (caused by Athelia rolfsii) in California are limited. The objectives of this study were to: (i) evaluate grafting with the resistant rootstock Maxifort for southern blight management in processing tomato and (ii) evaluate increasing the height of the graft union to further reduce incidence of southern blight in grafted plants. We evaluated two cultivars (Heinz 5608 or Heinz 8504) and a grafting factor with three levels (grafted to Maxifort rootstock with standard scion height, grafted to Maxifort rootstock at a tall height, and nongrafted) in a field study with natural inoculum or in inoculated greenhouse experiments. Southern blight severity was low in both greenhouse experiments in 2018 and 2019, and no consistent trends were observed. In field experiments in 2018 and 2019, mean incidence in nongrafted plots was 6.2 to 17.0 times higher when compared with either the standard or tall grafted treatments. Southern blight was numerically lower in tall grafted plots compared with standard, but the magnitude was small and not statistically significant. Based on our studies, grafting can reduce losses of processing tomato in California to southern blight, but increasing the height of the graft union does not offer a tangible benefit.

Tomato spotted wilt orthotospovirus (TSWV) causes substantial economic loss to tomato production, and the Sw-5b resistance gene is widely deployed for management. Here, we show (i) the emergence of resistance-breaking (RB) TSWV strains in processing and fresh market tomato production in California over the past ten years, and (ii) evolutionary relationships with RB strains from other areas. A specific RT-PCR test was used to show the C118Y RB strain that emerged in Fresno County in 2016 quickly became predominant in the central production area and remained so through this study. In 2021, the C118Y strain was detected in the Northern production area, and was predominant in 2022. However, in 2023, the C118Y strain was unexpectedly detected in fewer spotted wilt samples from resistant varieties. This was due to emergence of the T120N RB strain, previously known to occur in Spain. A specific RT-PCR test was developed and used to show that the T120N RB strain was predominant in Colusa and Sutter counties (detected in 75–80% of samples), and detected in ~50% of samples from Yolo County. Pathogenicity tests confirmed California isolates of the T120N strain infected Sw-5b tomato varieties and induced severe symptoms. Another RB strain, C118F, was associated with spotted wilt samples of Sw-5 varieties from fresh market tomato production in southern California. Phylogenetic analyses with complete NSm sequences revealed that the C118Y and T120N RB strains infecting resistant processing tomato in California emerged locally, whereas those from fresh market production were more closely related to isolates from Mexico. Thus, widespread deployment of this single dominant resistance gene in California has driven the local emergence of multiple RB strains in different tomato production areas and types. These results further emphasize the need for ongoing monitoring for RB strains, and identification of sources of resistance to these strains.

Genetic diversity of Alternaria alternata isolated from tomato in California assessed using RAPDs

Communicating risk to the public continues to be a challenge for public health practitioners working in the area of climate change. We conducted a scoping literature review on the evaluation of risk communication for extreme weather and climate change to inform local public health messaging, consistent with requirements under the Ontario Public Health Standards (OPHS), which were updated in 2018 to include effective communication regarding climate change and extreme weather. Search strategies were developed by library information specialists and used to retrieve peer-reviewed academic and grey literature from bibliographic databases (Medline, Embase, Scopus and CINAHL) and Google country specific searches, respectively. The search strategy was validated through a workshop with experts and community stakeholders, with expertise in environment, health, emergency management and risk communication. A total of 43 articles were included. These articles addressed issues such as: climate change (n = 22), flooding (n = 12), hurricane events (n = 5), extreme heat (n = 2), and wild fires (n = 2). Studies were predominantly from the US (n = 14), Europe (n = 6) and Canada (n = 5). To meet the OPHS 2018, public health practitioners need to engage in effective risk communication to motivate local actions that mitigate the effects of extreme weather and climate change. Based on the scoping review, risk communication efforts during short-term extreme weather events appear to be more effective than efforts to communicate risk around climate change. This distinction could highlight a unique opportunity for public health to adapt strategies commonly used for extreme weather to climate change.

Background: Both extreme weather and climate change have been linked to distress and at times mental health problems. Pro-environmental actions have often been related to higher distress. The uncertainty distress model (Freeston et al., 2020) proposes that in real-world situations, perceptions of threat and uncertainty contribute to distress. The aim of this study is to integrate variables from these two literatures and examine their relationships. Method: A community sample (n=327) was recruited and completed an online survey. Network analysis was used to analyse the relationships between the variables. Exposure to extreme weather, perceptions of climate change, climate change distress and pro-environmental action were measured along with symptoms of adjustment disorder and post-traumatic stress disorder, and uncertainty intolerance and behaviours. Results: There was variable exposure to extreme weather, but greater exposure was associated with more severe post-traumatic symptoms. Pro-environmental action was associated with greater severity of adjustment disorder symptoms. The perception that climate change was happening now was linked positively to pro-environmental action and negatively to perceptions of uncertainty about whether climate change was happening. Discussion: The results replicate several findings from the emerging climate change distress literature and are consistent with some predictions of the uncertainty distress model, but not others. Uncertainty as to whether climate change is happening now may be a less distressing position. Research that simultaneously considers extreme weather and climate change may help understanding the range of complex responses that may arise as the frequency of extreme weather increases and evidence for anthropogenic climate change strengthens. Key learning aims (1) To consider why the uncertainty distress model may be an appropriate framework to understand responses to extreme weather and climate change. (2) To consider how the perceived proximity of climate change may play a role in peoples’ emotional and behavioural responses to climate change. (3) To consider some of the variables that are linked to pro-environmental action. (4) To consider whether an uncertainty-based understanding of extreme weather and climate change has helpful implications for practice.

Tomato spotted wilt virus (TSWV; species Tomato spotted wilt orthotospovirus; genus Orthotospovirus; family Tospoviridae) is a thrips-transmitted virus that can cause substantial economic losses to many crops, including tomato (Solanum lycopersicum). Since 2005, TSWV emerged as an economically important virus of processing tomatoes in the Central Valley of California, in part due to increased populations of the primary thrips vector, western flower thrips (WFT; Frankliniella occidentalis). To develop an understanding of the epidemiology of TSWV in this region, population densities of WFT and incidence of TSWV were monitored in California’s processing tomato transplant-producing greenhouses and associated open fields from 2007 to 2013. Thrips were monitored with yellow sticky cards and in tomato flowers, whereas TSWV incidence was assessed with indicator plants and field surveys for virus symptoms. All thrips identified from processing tomato fields were WFT, and females were three-fold more abundant on sticky cards than males. Symptoms of TSWV infection were observed in all monitored processing tomato fields. Incidences of TSWV ranged from 1 to 20%, with highest incidence found in late-planted fields. There was no single primary inoculum source, and inoculum sources for thrips/TSWV varied depending on the production region. These results allowed us to develop a model for TSWV infection of processing tomatoes in the Central Valley of California. The model predicts that low levels of primary TSWV inoculum are amplified in early-planted tomatoes and other susceptible crops leading to highest levels of infection in later-planted fields, especially those with high thrips populations. Based upon these findings, an integrated pest management (IPM) strategy for TSWV in processing tomatoes in California was devised. This IPM strategy focuses on strategic field placement (identification of high-risk situations), planting TSWV- and thrips-free transplants, planting resistant varieties, monitoring for TSWV symptoms and thrips, roguing infected plants, thrips management targeting early generations, extensive sanitation after harvest, and strategic cropping to avoid overlap with winter bridge crops.

The existing body of research into the environmental and socio-economic benefits of green infrastructure supports the case for it to be positioned as a form of critical infrastructure, particularly in urban settings. It is broadly recognized that extreme weather and climate change pose significant risks to critical infrastructure systems linked to the provision of services, including electricity, water, communications, and transport, and consequently risk assessments and associated adaptation strategies are common practice. However, although green infrastructure is also at risk from extreme weather and climate change, threatening the realization of benefits that it can deliver in urban settings, associated risks to green infrastructure are not widely understood or assessed in practice. This paper discusses the status of existing research on this topic and uses this as a foundation for a Greater Manchester (UK) case study that assesses the risk of low water availability to grassed areas, which represent a key element of the city-region’s green infrastructure. In doing so, the paper demonstrates how risks linked to extreme weather and climate change can be assessed spatially to inform green infrastructure planning. In summary, this paper aims to raise awareness of extreme weather and climate change risk to urban green infrastructure, present an empirical case study and associated methodological approach on this topic, and ultimately support efforts to enhance the resilience of urban green infrastructure to extreme weather and climate change.

The link between extreme weather and climate change is being highlighted in ever more countries. Increased public understanding of this issue is essential for policymaking, both in terms of climate change mitigation and adaptation. As social media are becoming central to the exchange of information in society, the purpose is to analyze what generates intensified attention to the connection between extreme weather and climate change in digital communication. This is done by examining periods of intensified co-occurrence of mentions of extreme weather and climate change on English-language Twitter (N = 948,993). Our quantitative analysis suggests that during the period 2008–2017 the years 2010, 2011 and 2017 exhibit a considerable increase in ‘causality discourse’, i.e. tweets that articulate the topic of climate change + extreme weather, in comparison with earlier years. These periods of significant growth are interpreted as involving dynamic relationships between three factors, namely mediated highlighting of previous or ongoing extreme-weather events (extreme-event factor); connection of extreme weather to climate change by traditional media or other intermediaries (media-driven science communication factor); and actions of individual users (digital-action factor). Through a qualitative discourse analysis, how these factors jointly generate increasing attention to ‘causality discourse’ is more closely explored for the case of 2017.

Many countries apply import barriers for processing tomatoes, but the European Union is the main producer that uses export and production subsidies. We modeled and measured the potential impacts on global markets and the California industry that would result from reductions in trade barriers (such as import tariffs) and subsidies for the European Union's processing tomato industry. A multiequation simulation model showed that reducing trade barriers in Europe and elsewhere (including the United States) by 50% would raise the market price for California tomatoes by about 6%, improve net returns to California processing tomato producers by $34 million per year, and improve net returns to California tomato processors by $19 million per year. We also found that a 50% reduction in EU domestic support would improve the net returns of California producers and processors by about $8.5 million per year. Based on these results, we believe that negotiating reductions in subsidies, and especially in global trade barriers, would make economic sense for the California processing tomato industry.

Public lands provide many ecosystem services and support diverse plant and animal communities. In order to provide these benefits in the future, land managers and policy makers need information about future climate change and its potential effects. In particular, weather extremes are key drivers of wildfires, droughts, and false springs, which in turn can have large impacts on ecosystems. However, information on future changes in weather extremes on public lands is lacking. Our goal was to compare historical (1950-2005) and projected mid-century (2041-2070) changes in weather extremes (fire weather, spring droughts, and false springs) on public lands. This case study looked at the lands managed by the U.S. Forest Service across the conterminous United States including 501 ranger district units. We analyzed downscaled projections of daily records from 19 Coupled Model Intercomparison Project 5 General Circulation Models for two climate scenarios, with either medium-low or high CO2 - equivalent concentration (RCPs 4.5 and 8.5). For each ranger district, we estimated: (1) fire potential, using the Keetch-Byram Drought Index; (2) frequency of spring droughts, using the Standardized Precipitation Index; and (3) frequency of false springs, using the extended Spring Indices. We found that future climates could substantially alter weather conditions across Forest Service lands. Under the two climate scenarios, increases in wildfire potential, spring droughts, and false springs were projected in 32-72%, 28-29%, and 13-16% of all ranger districts, respectively. Moreover, a substantial number of ranger districts (17-30%), especially in the Southwestern, Pacific Southwest, and Rocky Mountain regions, were projected to see increases in more than one type of weather extreme, which may require special management attention. We suggest that future changes in weather extremes could threaten the ability of public lands to provide ecosystem services and ecological benefits to society. Overall, our results highlight the value of spatially-explicit weather projections to assess future changes in key weather extremes for land managers and policy makers.

Organic wastes diverted from landfills can reduce greenhouse gas emissions and are used as supplemental nutrient sources for agricultural crops after they are composted. In California, compost should be applied in the fall to processing tomatoes (Solanum lycopersicum L.) to avoid delaying field preparation and transplanting in the spring. The objective of this study was to determine soil nitrogen (N) mineralization following fall application of greenwaste compost (GWC) based on the change of mineral N during a 4 month in‐field buried bag soil incubation in 2 prospective subsurface drip‐irrigated processing tomato fields (PTF1 and PTF2). GWC rates of 0, 11, 22, and 34 Mg ha−1 were evaluated in PTF1 and PTF2 in October 2019. Very dry surface soil conditions in fall 2019 and the disruptive procedure used to prepare soil for in‐field incubation using the buried bag method led us to calculate net N mineralization after adjusting for the initial mineral N concentration of the unamended (0 Mg ha−1) control. The adjusted net N mineralization was significantly less in PTF1 (8.6 mg N kg−1) than PTF2 (16.4 mg N kg−1) and the estimated net N mineralization rate of the surface 0–15 cm soil depth following GWC application to PTF1 was less than PTF2 (1.6–1.9 vs. 2.3–3.1 kg N ha−1 week−1). In‐field incubation requires soil disturbance that likely affected N mineralization and additional research should consider the feasibility of using pretreatments or pre‐incubations to account for disruption to antecedent soil conditions.

Although the need for agriculture to adapt to climate change is well established, there is relatively little research within a UK context that explores how the risks associated with climate change are perceived at the farm level, nor how farmers are adapting their businesses to improve resilience in the context of climate change. Based on 31 in-depth, qualitative interviews (15 with farmers and 16 with stakeholders including advisors, consultants and industry representatives) this paper begins to address this gap by exploring experiences, attitudes and responses to extreme weather and climate change. The results point to a mixed picture of resilience to climate risks. All interviewees had experienced or witnessed negative impacts from extreme weather events in recent years but concern was expressed that too few farm businesses are taking sufficient action to increase their business resilience to extreme weather and climate change. Many farmers interviewed for this research did not perceive adaptation to be a priority and viewed the risks as either too uncertain and/or too long-term to warrant any significant investment of time or money at present when many are preoccupied with short-term profitability and business survival. We identified a range of issues and barriers that are constraining improved resilience across the industry, including some lack of awareness about the type and cost-effectiveness of potential adaptation options. Nevertheless, we also found evidence of positive actions being taken by many, whether in direct response to climate change/extreme weather or as a result of other drivers such as soil health, policy and legislation, cost reduction, productivity and changing consumer demands. Our findings reveal a number of actions that can help enable adaption at the farm level including improved industry collaboration, farmer-to-farmer learning, and the need for tools and support that take into account the specificities of different farming systems and that can be easily tailored or interpreted to help farmers understand what climate change means for their particular farm and, crucially, what they can do to increase their resilience to both extreme weather and longer term climate risks.

When tropical cyclone Winston hit Fiji on 20 February 2016, it became the strongest storm recorded in the southern hemisphere and the second strongest storm ever recorded in the world. Forty-four people died as a result of the superstorm, and the ongoing governmental recovery plans have estimated nearly three billion Fijian dollars (£1.1 billion) in damages. Fijian Prime Minister Frank Bainimarama, in a national address following Winston, stated ‘almost no part of our nation has been left unscarred’. This paper explores the adaptation measures for extreme weather and climate change in Fiji following Winston, as well as the author’s experiences both as a survivor of Winston and as a volunteer aid-relief worker living in Suva, the Fijian capital, at the time of the superstorm. Notably, Winston struck 5 days after Fiji became the first nation to ratify the United Nations Climate deal agreed to by 195 nations in Paris in December 2015. Many Pacific island nations have played a vital role in leading the global dialogue on climate change. In the lead up to the Paris summit, Prime Minister Bainimarama, stressed that ‘unless the world acts decisively in the coming weeks to begin addressing the greatest challenge of our age, then the Pacific, as we know it, is doomed.’ This is undoubtedly true and a global response is desperately needed, but equally true is the importance for such a reaction to be a cultural and faith-integrated process across multiple scales, ranging from village and community to regional, in scope. One critical aspect of extreme weather and climate change response in the Pacific is migration. However, the impacts of migration include organizing, adaptation and urban poverty, a further source of vulnerability. Consequently, human mobility in response to extreme weather and climate change is far more complex than originally addressed and is deserving of deeper consideration.

Oviposition patterns of Heliothis zea, Manduca spp., Spodoptera exigua, and Trichoplusia ni were studied in processing-tomato fields of northern California. The initiation of egg laying appears to be related to flower formation, with peak egg deposition occurring in relation to the peak number of open flowers per plant for H. zea, S. exigua, and T. ni. Oviposition by Manduca spp. increases as the season progresses. All species deposit most of their eggs on leaves of the terminal half of the branch. The majority of eggs are located on the ventral leaf surface, within one leaf of the inflorescence. From these data, it is possible to estimate the number of plants that would have to be sampled to find an egg of one species at a given egg density.

During the 2017 growing season, high-tunnel-grown fresh market tomatoes from an Indiana producer were identified with virus-like symptoms. Foliar symptoms included necrotic spotting and flecking, and stems had necrotic streaks. Fruit had an extensive pattern of necrotic concentric lines, spots, and scabbing, making them unsaleable. Around 5% of the plants exhibited symptoms. Degenerate Ilarvirus group-specific primers identified the virus as belonging to the Ilarvirus group. Primers designed to amplify the coat protein identified the virus as tomato necrotic spot virus, previously only reported in processing tomatoes in California.