Recombination in the wheat stem rust pathogen mediated by an indigenous barberry species in Spain

The comeback of wheat stem rust in Europe, caused by Puccinia graminis f. sp. tritici, and the prevalence of the alternate (sexual) host in local areas have recently regained attention as a potential threat to European wheat production. The aim of this study was to investigate a potential epidemiological link between the aecia found on an indigenous barberry species and stem rust infections on nearby cereals and grasses. Aecial infections collected from Berberis vulgaris subsp. seroi were inoculated on a panel of susceptible genotypes of major cereal crop species. In total, 67 stem rust progeny isolates were recovered from wheat (51), barley (7), and rye (9), but none from oat, indicating the potential of barberry derived isolates to infect multiple cereals. Molecular genotyping of the progeny isolates and 20 cereal and grass stem rust samples collected at the same locations and year, revealed a clear genetic relatedness between the progeny isolated from barberry and the stem rust infections found on nearby cereal and grass hosts. Analysis of Molecular Variance indicated that variation between the stem rust populations accounted for only 1%. A Principal Components Analysis using the 62 detected multilocus genotypes also demonstrated a low degree of genetic variation among isolates belonging to the two stem rust populations. Lastly, pairwise comparisons based on fixation index (Fst), Nei's genetic distances and number of effective migrants (Nm) revealed low genetic differentiation and high genetic exchange between the two populations. Our results demonstrated a direct epidemiological link and functionality of an indigenous barberry species as the sexual host of P. graminis in Spain, a factor that should be considered when designing future strategies to prevent stem rust in Europe and beyond

Plant pathogen infection risk and climate change in the Nordic and Baltic countries

Climate change and global warming are already affecting food production, and the impact is predicted to intensify in the future. Previous studies have been based on global data and have provided general information about climate change effects on food production. Regional high-resolution data are, however, needed to evaluate the effect of future scenarios of climate change to support strategic and tactical planning to safeguard food production. Here, we provide results on the future potential distribution range of fungal plant pathogens in the Nordic and Baltic countries. This is done using regional climate model data at 12.5 km horizontal resolution. The temperature dependent infection risk and species richness are calculated using data for 80 plant pathogens. Within the region the studied pathogens will in most cases thrive more and be more abundant in a warmer climate; leading to a longer infection risk season and the introduction of new pathogens. This applies to all emissions scenarios, even though the effects are stronger with high emissions. Our results indicate that plant diseases will increase, and this will negatively affect crop production and food security

Beekeeping for recuperation?

I mötet med djur och natur upplever människor ofta att de befinner sig i, och är delaktiga av ett större sammanhang. Naturens positiva inverkan på människors hälsa har sedan länge varit allmänt känd och på senare år även med forskning som stöd. Med ett eget intresse för biodling och de senaste åren ett allt större medialt fokus på bin och pollinerare väcktes min nyfikenhet för vad biodling egentligen innebär och vad det ger en biodlare att hålla på med biodling. Syftet med arbetet blev att ta reda på vad biodlare upplever att biodling egentligen innebär för dem, vad som är själva essensen i biodling. Frågeställning blev därmed: Vad är det som lockar till att bli biodlare, och till att fortsätta vara det? Genom intervjuer med tre olika biodlare söktes deras upplevelse av fenomenet biodling och efter att ha analyserat intervjuerna framträdde resultatet med fem olika konstituenter: Ursprungligt intresse för djur och natur; Fascination över binas sätt att leva och överleva; Omvårdnad av bina, men även om sig själv; Glädjen att få dela med sig och Årstidsväxlingarnas återkommande rytm - aktivitet och vila. Genom en litteraturstudie fördjupades också kunskapen inom området biodling och inom området för naturens positiva inverkan på människors hälsa.In contact with animals and nature people often experience themself as part of something bigger. It has long been known to people that nature has a positive effect on personal health, which recent research has proven to be true. With my own personal interest in bees and through medias exposure of bees and pollinators lately, I have become curious about what beekeeping really is, what makes people become beekeepers and why they continue as beekeepers. The aim with my research was to find out what the essens / the phenomenon of beekeeping means to beekeepers.The questions I wanted to find answers to were: What makes someone become a beekeeper, and what makes one continue as a beekeeper? Through interwievs with three beekeepers I searched for the essens or the phenomenon in beekeeping and analysing the material resulted in five different constituents:An interest in animals and nature; Fascination of the bees way of living and surviving; Caretaking of the bees, but also caring for oneself; The joy of sharing, and The rhytm of the yearly seasons - activity and rest. Through a literature review, increased knowledge was gained both about beekeeping and also about natures positive effect on peoples health

Vegetation type determines spore deposition within a forest–agricultural mosaic landscape

Predicting fungal community assembly is partly limited by our understanding of the factors driving the composition of deposited spores. We studied the relative contribution of vegetation, geographical distance, seasonality and weather to fungal spore deposition across three vegetation types. Active and passive spore traps were established in agricultural fields, deciduous forests and coniferous forests across a geographic gradient of ∼600 km. Active traps captured the spore community suspended in air, reflecting the potential deposition, whereas passive traps reflected realized deposition. Fungal species were identified by metabarcoding of the ITS2 region. The composition of spore communities captured by passive traps differed more between vegetation types than across regions separated by >100 km, indicating that vegetation type was the strongest driver of composition of deposited spores. By contrast, vegetation contributed less to potential deposition, which followed a seasonal pattern. Within the same site, the spore communities captured by active traps differed from those captured by passive traps. Realized deposition tended to be dominated by spores of species related to vegetation. Temperature was negatively correlated with the fungal species richness of both potential and realized deposition. Our results indicate that vegetation may be able to maintain similar fungal communities across distances, and likely be the driving factor of fungal spore deposition at landscape level

Tomato diseases, quality, yield and pesticide use : a field study in Nicaragua

Nicaraguan farmers have for a long time struggled with tomato production. The primary problem has been Begomovirus infection, which devastated the tomato production in the country in the 1990's. In the battle against the Begomovirus other problems in the native tomato production have been neglected. The overall goal with these projects was to identify common tomato diseases and to evaluate their effect on yield and quality of the tomato fruits at different nitrogen levels. This report contains two separate theses (chapter 2 and 3). The results of the studies are based on the same field experiments. To increase the understanding about local farming conditions (chapter 1), interviews were made at two locations. During the interviews the farmers were asked questions about the farms, their production and pesticide use. Today, the farmers overuse chemical products to control different pests. The Nicaraguan farmers in general have a strong belief that pesticides are the solution of all their agricultural problems. The thesis in chapter 2 deals with the effect of nitrogen on some diseases of tomato. The symptoms that appeared in the field experiment indicated that the plants were not infected by the suspected pathogens and lab results showed that symptoms on the plants were caused by two other diseases: bacterial wilt and powdery mildew (causing agents: Ralstonia solanacearum and Leveilulla taurica). The results showed that plants fertilised with double the normal amount of nitrogen were significantly more resistant to powdery mildew. There was also a significant difference between the varieties in severity of powdery mildew. Regarding bacterial wilt the results are ambiguous, one of the field experiments show no difference between the treatments but in the other experiment there was a considerably higher rate of infection in the to highest levels of nitrogen fertilisation. The aim of the study in chapter 3 was to evaluate the effects of nitrogen fertilization on the yield and quality of the tomato fruits and to evaluate the relations between the incidence of diseases and nitrogen fertilization on one hand and fruit quality on the other. The harvest was divided in good (marketable) and bad (not marketable) fractions. To evaluate the fruit quality, taste tests were carried out on the two first harvests and laboratory analyses of acid (% titratable acids) and sugar content (ºBrix) were measured on the second harvest. The results showed that the unfertilized plots had significantly lower foliar nitrogen content. The total harvest levels of the experiment were in similar range as the average harvest for the region (12-18 t/ha), but the marketable fraction was only between 39 and 50 % of the total yield. In the taste test, one of the varieties was significantly the most preferred variety, independent of fertilizing level. The high not marketable fraction was probably due to poor pollination and fruit set caused by high temperatures and heavy infections of Begomovirus and other diseases. It is also very important to identify the pathogen to know which diseases that are present in the field and how to treat them properly. A solution to many disease and quality problem could be a break in tomato production some time during the year to create a host free period for diseases and vectors.Nicaraguanska bönder har länge tvingats kämpa med problem i tomatodlingen. Det största problemet har varit infektion av Begomovirus, vilket fick katastrofala följder för tomatproduktionen på 1990-talet. I kampen mot Begomovirus glömdes andra problem i den inhemska tomatodlingen bort. Det övergripande målet med de här projekten var att identifiera vanliga tomatsjukdomar och utvärdera deras effekt på skörd och kvalitet på tomaterna vid olika kvävegivor. Rapporten innehåller två separata examensarbeten (kapitel 2 och 3). Resultaten från studierna bygger på samma fältexperiment. För att öka förståelsen om den inhemska tomatproduktionen (kapitel 1), intervjuades bönder i två byar. I intervjuerna ställdes frågor om gårdarna, produktionen och bekämpningsmedel. Idag finns en överanvändning av kemiska preparat för att kontrollera olika skadegörare och Nicaraguanska bönder har generellt sett en övertro på att bekämpningsmedel som en lösning på alla problem inom jordbruket. Examensarbetet i kapitel 2 handlar om effekten av kväve på vissa tomatsjukdomar. Symptomen som uppträdde i fält tydde på att det inte var de förväntade sjukdomarna och laboratorieresultaten visade att plantorna hade infekterats av två andra sjukdomar: bacterial wilt och mjöldagg (orsakad av Ralstonia solanacearum och Leveilulla taurica). Resultaten visade att plantorna som gödslats med dubbla normalgivan av kväve var mer motståndskraftiga mot mjöldagg, det fanns också en skillnad mellan sorterna när det gäller angrepp av mjöldagg. Angående bacterial wilt var resultaten tvetydiga, ett av fältförsöken visade ingen skillnad mellan behandlingarna, medan i det andra var det högre infektionsgrad i de högsta kvävegivorna. Syftet med studien i kapitel 3 var att utvärdera effekterna av kvävegödsling på skörden och kvalitén på tomaterna samt att utvärdera sambandet mellan förekomsten av sjukdom och mängden kväve å ena sidan och kvalitén å anda sidan. Skörden delades in i en bra (säljbar) och en dålig (icke säljbar) del. För att utvärdera fruktkvalitén gjordes smaktest på två skördar och laboratorieanalyser av syra (% titrerbar syra) och sockerinnehåll (ºBrix) på den andra skörden. Resultaten visade att ogödslade rutor hade signifikant lägre kväveinnehåll i blasten. Den totala skördenivån i fältförsöket var jämförbar med normala skördar i området (12-18 t/ha), men andelen säljbara frukter var endast 39 till 50 % av den totala skörden. Smaktesten visade att den ena sorten föredrogs av panelen oberoende av kvävegiva. Den höga andelen icke säljbara frukter berodde troligen på dålig pollination och fruktbildning orsakad av hög temperatur och kraftiga infektioner av Begomovirus och andra sjukdomar. Det är också mycket viktigt att identifiera patogener för att veta vilka sjukdomar som finns i fält och hur de bäst skall bekämpas. En lösning till många sjukdoms- och kvalitetsproblem skulle kunna vara att införa ett uppehåll i tomatodlingen någon gång under året, för att skapa en värdfri period för sjukdomar och vektorer

Scientific evidence of sustainable plant disease protection strategies for oilseed rape (Brassica napus) in Sweden: a systematic map

BackgroundOilseed rape (OSR; Brassica napus L.) is a highly valued crop for food, feed and industrial use. It is primarily grown in temperate climates, and over recent decades, its area of production and profitability have increased. Concurrently, several diseases negatively impact OSR production. Diseases caused by soil-borne pathogens, pose a risk of substantial yield loss since crop rotation schemes have become narrow as the time lapse between OSR crops in a field has been shortened. The aims of this paper were to provide an overview of plant protection measures available for OSR production and to identify knowledge gaps and areas where more research is needed.MethodsThis systematic map builds on a previously published protocol and follows the ROSES reporting standard. The search strategy was developed in collaboration with stakeholders and designed to cover available scientific evidence for OSR disease management in climate zones relevant for Scandinavian crop production (Dfc, Dfb, Cfb and Cfa in the Köppen-Geiger climate classification). Five scientific databases were used to identify peer-reviewed literature, complemented by additional searches performed in grey literature. Articles were screened at three stages: the title, abstract and full text. The eligible publications included studies of OSR crops, and all measures to control crop disease in agricultural fields were considered eligible interventions. The comparator was intervention and no intervention, and the yield per unit area, disease suppression or an increase in crop quality were determined to be outcomes of interventions. A basic assessment of the experimental design of each study was performed to assess its eligibility. All articles were coded based on the following categories: the location and climate zone, disease, pathogen, intervention and management method, outcome and study design. Articles not reporting original data but judged to be relevant (i.e., review papers, books and notes of registration of cultivars) were saved in a separate category called “books, reviews and reports”.Review findingsA total of 4633 articles were collected through systematic searches. After duplicates were removed, 3513 articles were included in the screening process. After screening at the title and abstract levels, 897 articles were evaluated at the full text level, and 118 articles comprised the studies that met the eligibility criteria of the systematic map. The country (Canada) and region (Europe) with the largest OSR crop production areas also contributed the highest number of articles. In total, 17 different diseases were reported, with black leg (syn. Phoma stem canker) being the most studied disease. Nineteen different intervention methods or management types were examined. Cultivar resistance and pesticide application were the most studied control measures.ConclusionWe report scientific studies on plant disease protection measures for OSR based on field trials where the results are intended to be directly implemented in crop production management. The map clearly provides an overview of research progress throughout the time period chosen, and it identifies knowledge gaps regarding important diseases where only a few studies have been published, for example, diseases caused by viruses

Model analysis of temperature impact on the Norway spruce provenance specific bud burst and associated risk of frost damage

The annual growth cycle of boreal trees is synchronized with seasonal changes in photoperiod and temperature. A warmer climate can lead to an earlier bud burst and increased risk of frost damage caused by temperature backlashes. In this study we analysed site- and provenance specific responses to interannual variation in temperature, using data from 18 Swedish and East-European provenances of Norway spruce (Picea abies), grown in three different sites in southern Sweden. The temperature sum requirements for bud burst, estimated from the provenance trials, were correlated with the provenance specific place of origin, in terms of latitudinal and longitudinal gradients. Frost damage had a significant effect on tree height development. Earlier timing of bud burst was linked to a higher risk of frost damage, with one of the sites being more prone to spring frost than the other two. The estimated provenance specific temperature sum requirements for bud burst were used to parametrize a temperature sum model of bud burst timing, which was then used together with the ensemble of gridded climate model data (RCP8.5) to assess the climate change impact on bud burst and associated risk of frost damage. In this respect, the simulated timing of bud burst and occurrence of frost events for the periods 2021-2050 and 2071-2100 were compared with 1989-2018. In response to a warmer climate, the total number of frost events in southern Sweden will decrease, while the number of frost events after bud burst will increase due to earlier bud burst timing. The provenance specific assessments of frost risk under climate change can be used for a selection of seed sources in Swedish forestry. In terms of selecting suitable provenances, knowledge on local climate conditions is of importance, as the gridded climate data may differ from local temperature conditions. A comparison with temperature logger data from ten different sites indicated that the gridded temperature data were a good proxy for the daily mean temperatures, but the gridded daily minimum temperatures tended to underestimate the local risk of frost events, in particular at the measurements 0.5 m above ground representing the height of newly established seedlings

Interdisciplinary insights into navigating the maze of landscape multifunctionality

Increasing demands for land to deliver multiple and sometimes conflicting services to people and nature have led to the development of an extensive body of research focussed on multifunctional landscapes. However, this has created both insight and confusion, as authors from a variety of disciplines have independently tackled the question of how to manage the trade-offs and synergies inherent in landscapes that are required to produce multiple functions and services. We employed an interdisciplinary perspective to formulate some key questions that researchers of multifunctional landscapes can use to identify blind spots. Our process resulted in a question-based analysis support scheme that supports reflection and recursive thinking about multifunctional landscapes, beginning with objective setting and visions for addressing it, grounded in baseline mapping, then assessing landscape functions and their single and multiple interactions; as well as the analysis of sensitivity to spatial and temporal dimensions. Other key points identified are the need for clarity and examination of unstated assumptions, from aims to definitions; accounting for scale; incorporating stakeholder needs throughout the process and applying suitable methods of measurement and aggregation. The focus on asking guided questions derives from the insight that there is no universal correct approach to multifunctional landscapes; the aim should instead be to find the most appropriate methods for the given circumstances and goals. Policy implications. Tackling current and future socio-ecological challenges is an interdisciplinary undertaking, necessitating collaborative efforts between research fields that each bring valuable and distinct insights. To effectively combat these challenges, multifunctional landscapes require a clear process and focused objective in their implementation. Multifunctionality should be seen as a means to an end, rather than an end in itself.Read the free Plain Language Summary for this article on the Journal blog.okade krav pa att landskap ska leverera flera och ibland motstridiga tjanster till manniskor och natur har lett till utvecklingen av en omfangsrik forskning med fokus pa multifunktionella landskap. Detta har skapat bade insikter och oklarheter, eftersom forskare fran en rad olika discipliner oberoende av varandra har tagit sig an fragan om hur man ska hantera de kompromisser och synergier som uppstar i landskap som maste producera flera olika funktioner och tjanster. Genom ett interdisciplinart perspektiv har vi formulerat nyckelfragor som forskare som studerar multifunktionella landskap kan anvanda for att identifiera sina blinda flackar. Var process resulterade i ett fragebaserat analysstod for reflektion och rekursivt tankande om multifunktionella landskap. Det borjar med malsattning och visioner for att adressera detta, som sedan forankras i kartlaggning av forutsattningar, och fortsatter med bedomning av landskapsfunktioner och hur de interagerar men enskilda eller flera andra landskapsfunktioner; samt med analys av kanslighet for rumsliga och tidsmassiga dimensioner. Andra centrala punkter som identifierats ar behovet av tydlighet och granskning av outtalade grundantaganden, fran mal till definitioner; att skalan tas i beaktande; inforlivande av intressenters behov genom hela processen och tillampning av lampliga metoder for matning och aggregering av information. Vart fokus pa att stalla vagledande fragor kommer fran insikten att det inte finns nagot universellt korrekt tillvagagangssatt for multifunktionella landskap; syftet bor istallet vara att hitta de mest lampliga metoderna for de givna omstandigheterna och malen. Betydelse for politiken. Att ta itu med nuvarande och framtida socioekologiska utmaningar ar ett interdisciplinart atagande som kraver samarbete mellan forskningsomraden som vart och ett bidrar med vardefulla och specifika insikter. For att mota dessa utmaningar pa ett effektivt satt kravs en tydlig process och ett fokuserat mal for implementeringen av multifunktionella landskap. Multifunktionalitet bor ses som ett medel for att na ett mal, snarare an ett mal i sig.Read the free Plain Language Summary for this article on the Journal blog

Genetic diversity of the pea root pathogen Aphanomyces euteiches in Europe

The oomycete pathogen Aphanomyces euteiches causes root rot in various legume species. In this study we focused on A. euteiches causing root rot in pea (Pisum sativum), thereby being responsible for severe yield losses in pea production. We aimed to understand the genetic diversity of A. euteiches in Europe, covering a north-to-south gradient spanning from Sweden, Norway and Finland to the UK, France and Italy. A collection of 85 European A. euteiches strains was obtained, all isolated from infected pea roots from commercial vining pea cultivation fields. The strains were genotyped using 22 simple-sequence repeat markers. Multilocus genotypes were compiled and the genetic diversity between individual strains and population structure between countries was analysed. The population comprising strains from Italy was genetically different and did not share ancestry with any other population. Also, strains originating from Finland and the eastern parts of Sweden were found to be significantly different from the other populations, while strains from the rest of Europe were more closely related. A subset of 10 A. euteiches strains from four countries was further phenotyped on two susceptible pea genotypes, as well as on one genotype with partial resistance towards A. euteiches. All strains were pathogenic on all pea genotypes, but with varying levels of disease severity. No correlation between the genetic relatedness of strains and virulence levels was found. In summary, our study identified three genetically distinct groups of A. euteiches in Europe along a north-to-south gradient, indicating local pathogen differentiation

Kunskapsbaserat växtskydd i praktiken - vilka faktorer spelar roll för lantbrukares beslutsfattande om växtskyddsåtgärder?

Vi har gjort en systematisk litteraturöversikt över hur ny kunskap om växtskydd når gårdsnivå. Frågor som vi har ställt till vårt material är: vilka hinder finns för implementering av ny forskning omkring växtskydd? Genom vilka kanaler når ny kunskap gården?Detta är en delstudie i ett projekt med både en naturvetenskaplig och en samhällsvetenskaplig del