Plant-parasitic nematodes (PPNs) are important pests that cause an estimated ten billion dollars of crop loss each year in the United States and over 100 billion dollars globally. The Animal and Plant Health Inspection Service (APHIS) within the U.S. Department of Agriculture maintains and updates the U.S. Regulated Plant Pest list. Currently, the number of PPNs regulated by APHIS includes more than 60 different species. This review focuses on the top ten most economically important regulated and emerging plant-parasitic nematodes and summarizes the diagnostics of morphological and some molecular features for distinguishing them. These ten major previously described nematode species are associated with various economically important crops from around the world. This review also includes their current distribution in the U.S. and a brief historical background and updated systematic position of these species. The species included in this review include three PPNs considered by the U.S. Department of Agriculture as invasive invertebrates Globodera pallida, Globodera rostochiensis, and Heterodera glycines; four regulated PPNs, namely Bursaphelenchus xylophilus, Meloidogyne fallax, Ditylenchus dipsaci, and Pratylenchus fallax; and the three emerging PPNs Meloidogyne chitwoodi, Meloidogyne enterolobii, and Litylenchus crenatae mccannii.

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Citrullus amarus (CA) (previously known as Citrullus lanatus var. citroides) accessions collected in southern Africa are known to have resistance to root-knot nematodes (RKN) and are suitable rootstocks for grafted watermelon. The objective of this study was to conduct a comparative metabolomics analysis and identify unique metabolites in roots of CA accessions versus roots of watermelon cultivars (Citrullus lanatus (Thunb.) Matsum. and Nakai var. lanatus; CL). Nuclear magnetic resonance (NMR) technology and principal component analysis (PCA) were used to analyze and compare metabolic profiles of seven CA accessions resistant to RKN along with two RKNsusceptible watermelon cultivars (Charleston Gray and Crimson Sweet). Calculation of the Mahalanobis distance revealed that the CA United States Plant Introduction (PI) 189225 (Line number 1832) and PI 482324 (1849) have the most distinct metabolic profiles compared with the watermelon cultivars Charleston Gray and Crimson Sweet, respectively. Several amino acids identified in the CA accessions were reported in previous studies to have a nematicidal effect. The results in this study indicate that roots of watermelon accessions collected in the wild are rich in metabolic compounds. These metabolic compounds may have been diminished in watermelon cultivars as a consequence of many years of cultivation and selection for desirable fruit qualities.

Digital Earth (DE) education provides students with geospatial knowledge and skills to locate, measure, and solve geographic problems on Earth's surface. The rapid development of geospatial technology has promoted a new vision of DE to embrace data infrastructure, social networks, citizen science, and human processes on Earth. The high demand for a geospatial workforce also calls for an ever-changing, diverse form of learning experiences. Limited efforts, however, have been made regarding DE education to adapt to this changing landscape, with most interventions falling short of expectations. This chapter gives an overview of current teaching and learning structures with DE technologies. Successes and obstacles for K-12 education are explored first, followed by classroom technologies and experiential learning and outreach exercises such as academic certificates and internships in higher education. Taking the geospatial intelligence model from the U.S. Geospatial Intelligence Foundation (USGIF) as an example, recent advancements in DE education for professional careers are described via its geospatial competencies, hierarchical frameworks, and credentials. In alignment with the principles of DE development, future DE education calls for an integrated learning framework of open data, real-world context, and virtual reality for better preparedness of our students in the geospatial world.

The Water-Energy-Food (WEF) Nexus concept has great potential for understanding a region's vulnerability to climate change. This paper examines individual components that form the supporting pillars of the nexus in Central and Eastern European (CEE) countries. An overview of specific CEE political environments that govern economic and environmental policies are examined to select several domains representing higher risks to society, environment and economies of selected countries, together with evaluation of extant interlinkages between climate change, agriculture and the WEF nexus. While a variety of studies quantify and analyze climate change impacts on water availability, crop yields, yield variability, or alternative energy needed to mitigate global warming effects, this paper shows there is no clear evidence of a nexus-based integration to help manage or mitigate extreme future climate change-related events in the region. The study provides a model for supporting WEF pillars and advances recommendations for consideration of the nexus approach in relation to climate adaptation.