International Evaluation of Research and Doctoral Training at the University of Helsinki 2005-2010: RC-Specific Evaluation of SSA - Science of Sustainable Agriculture

Cold winters and geographic isolation have hitherto protected the Nordic countries from many plant pathogens and insect pests, leading to a comparatively low input of pesticides. The changing climate is projected to lead to a greater rise in temperature in this region, compared to the global mean. In Scandinavia, a milder and more humid climate implies extended growing seasons and possibilities to introduce new crops, but also opportunities for crop pests and pathogens to thrive in the absence of long cold periods. Increased temperatures, changed precipitation patterns and new cultivation practices may lead to a dramatic change in crop health. Examples of diseases and insect pest problems predicted to increase in incidence and severity due to global warming are discussed.

/pdf/the-impact-of-global-warming-on-plant-diseases-and-insect-atd2if5mhs.pdf

The impact of global warming on plant diseases and insect vectors in Sweden

Viruses are among the most significant biotic constraints in potato production. In the century since the discovery of the first potato viruses we have learned more and more about these pathogens, and this has accelerated over the last decade with the advent of high-throughput sequencing in the study of plant virology. Most reviews of potato viruses have focused on temperate potato production systems of Europe and North America. However, potato production is rapidly expanding in tropical and subtropical agro-ecologies of the world in Asia and Africa, which present a unique set of problems for the crop and affect the way viruses can be managed. In this chapter we review the latest discoveries in potato virology as well as the changes in virus populations that have occurred over the last 50 years, with a particular focus on countries in the (sub-)tropics. We also review the different management approaches including use of resistance, seed systems, and cultural approaches that have been employed in different countries and reflect on what can be learnt from past research on potato viruses, and what can be expected in the future facing climate change.

/pdf/viral-diseases-in-potato-41kcm9xb4u.pdf

Viral diseases in potato

After clarifying the relationship between the closely related concepts of ecology and epidemiology as they are used in plant virology, this article provides a historical perspective on the subject before discussing recent progress and future prospects. Ecology focuses on virus populations interacting with host populations within a variable environment, while epidemiology focuses on the complex association between virus and host plant, and factors that influence spread. The evolution and growth of plant virus ecology and epidemiology since its inception to the present day, and the major milestones in its development, are illustrated by examples from influential historical reviews published in the Annals of Applied Biology over the last 100 years. Original research papers published in the journal are used to illustrate important ecological and epidemiological principles and new developments in both fields. Both areas are multifaceted with many factors influencing host plants, and virus and vector behaviour. The highly diverse scenarios that arise from this process influence the virus population and the spatiotemporal dynamics of virus distribution and spread. The review then describes exciting progress in research in the areas of molecular epidemiology and ecology, and understanding virus–vector interactions. Application of new molecular techniques has greatly accelerated the rate of progress in understanding virus populations and the way changes in these populations influence epidemics. Viruses cause direct and plant-mediated indirect effects on insect vectors by modifying their life cycles, fitness and behaviour, and one of the most fascinating recent fields of research concerns plant-mediated indirect virus manipulation of insect vector behaviour that encourages virus spread. Next, the review describes the current state of knowledge about spread of plant viruses at the critical agro-ecological interface between managed and natural vegetation. There is an urgent need to understand how viruses move in both directions between the two and be able to anticipate these kinds of events. To obtain an understanding of, and ability to foresee, such events will require a major research effort into the future. The review finishes by discussing the implications of climate change and rapid technological innovation for the types of research needed to avoid virus threats to future world food supplies and plant biodiversity. There has been lamentably little focus on research to determine the magnitude of the threat from diseases caused in diverse plant virus pathosystems under different climate change scenarios. Increasing technological innovation offers many opportunities to help ensure this situation is addressed, and provide plant virus ecology and epidemiology with a very exciting future.

Plant virus ecology and epidemiology: historical perspectives, recent progress and future prospects

Potato virus Y (PVY) and Potato mop-top virus (PMTV) are viruses whose geographical distribution is expanding and economic losses are increasing, in contrast to most of other viruses infecting potato crops. Most potato cultivars lack broad-spectrum resistance to the new, genetically complex strains of PVY, and no efficient resistance to PMTV is known in potato. Control of the vectors of these viruses is not an efficient or possible strategy to prevent infections. Studies on molecular virus-host interactions can discover plant genes that are important to viral infection or antiviral defence. Both types of genes may be utilized in resistance breeding, which is discussed in this paper. The advanced gene technologies provide means to fortify potato cultivars with effective virus resistance genes or mutated, non-functional host factors that interfere with virus infection.

Elucidation of virus-host interactions to enhance resistance breeding for control of virus diseases in potato.

Potato mop-top virus (PMTV; genus Pomovirus; family Virgaviridae) is transmitted bythesoil-borneSpongosporasubterraneaf.sp.subterranea,aprotoctistthatcauses powdery scab on potato. PMTV is distributed widely in the potato growing areas in South and North America, Japan and northwestern Europe. This article reviews the current knowledge on detection, distribution and control of PMTV with focus on the Baltic Sea region. Since the 1980s, PMTV has caused great economic losses to potato production in the Nordic countries (Norway, Sweden, Denmark and Finland), but its occurrence in other countries of the Baltic Sea region remained unknown. To fill this knowledge gap, harmonised sampling and virus detection procedures including bioassays and serological and molecular methods were employed by 21 research institutions to detect PMTV in potato tubers and soil samples in 2005‐2008. Potato growing areas were widely contaminated with PMTV in the Nordic countries. Only the main seed potato production area in northern Sweden and the High Grade seed potato production zone in Finland were negative for PMTV. Intensive and

J. Mihailova

Papers

Detection, distribution and control of Potato mop‐top virus, a soil‐borne virus, in northern Europe