A novel multi-head CNN design to identify plant diseases using the fusion of RGB images

Plant diseases and insect pests cause a significant threat to agricultural production. Early detection and diagnosis of these diseases are critical and can reduce economic losses. The recent development of deep learning (DL) benefits various fields, such as image processing, remote sensing, medical diagnosis, and agriculture. This work proposed a novel approach based on DL for plant disease detection by fusing RGB and segmented images. A multi-headed DenseNet-based architecture was developed, considering two images as input. We evaluated the model on a public dataset, PlantVillage, consisting of 54183 images with 38 classes. The fivefold cross-validation technique achieved an average accuracy, recall, precision, and f1-score of 98.17%, 98.17%, 98.16%, and 98.12%, respectively. The proposed approach can distinguish various plant diseases with different characteristics by image fusion. The high success rate with low standard deviation proves the robustness of the model, and the model can be integrated into plant disease detection and early warning system.     

Plant Quarantine as a Measure Against Invasive Alien Species: The Framework of the International Plant Protection Convention and the plant health regulations in the European Union

The introduction of several plant pests into Europe in the 19th century with disastrous consequences called for the development of plant quarantine measures to prevent the spread and introduction of pests of plants and plant products. With the purpose of harmonising these measures, and of promoting measures for pest control, the International Plant Protection Convention (IPPC) was developed to address organisms that are both directly and indirectly injurious to plants. It supplies a framework for measures against invasive alien species according to the Convention on Biological Diversity, as far as they are plant pests. Three examples of invasive alien species within the scope of the IPPC are given in the article: the fungus Ceratocystis fagacearum, the pinewood nematode Bursaphelenchus xylophilus and the flatworm Arthurdendyus triangulatus. In its 1997 revision, the IPPC provides for the establishment of International Standards for Phytosanitary Measures, being acknowledged by the Agreement on the Application of Sanitary and Phytosanitary Measures of the World Trade Organisation. Standards most important for invasive alien species are those on pest risk analysis, on requirements for the establishment of pest-free areas, on surveillance, on pest eradication programmes, and on the import and release of exotic biological agents. Phytosanitary regulations in the European Union (EU) have been harmonised and up to now have regulated about 300 plant pests. The requirements also have a protective horizontal effect against the unintentional introduction of many other species, but the existing broader IPPC mandate for alien plant pests is not fully applied by the EU regulations. This revised version was published online in July 2006 with corrections to the Cover Date.     

Urban trees: bridge-heads for forest pest invasions and sentinels for early detection

Urban trees have been increasingly appreciated for the many benefits they provide. As concentrated hubs of human-mediated movement, the urban landscape is, however, often the first point of contact for exotic pests including insects and plant pathogens. Consequently, urban trees can be important for accidentally introduced forest pests to become established and potentially invasive. Reductions in biodiversity and the potential for stressful conditions arising from anthropogenic disturbances can predispose these trees to pest attack, further increasing the likelihood of exotic forest pests becoming established and increasing in density. Once established in urban environments, dispersal of introduced pests can proceed to natural forest landscapes or planted forests. In addition to permanent long-term damage to natural ecosystems, the consequences of these invasions include costly attempts at eradication and post establishment management strategies. We discuss a range of ecological, economic and social impacts arising from these incursions and the importance of global biosecurity is highlighted as a crucially important barrier to pest invasions. Finally, we suggest that urban trees may be viewed as ‘sentinel plantings’. In particular, botanical gardens and arboreta frequently house large collections of exotic plantings, providing a unique opportunity to help predict and prevent the invasion of new pests, and where introduced pests with the capacity to cause serious impacts in forest environments could potentially be detected during the initial stages of establishment. Such early detection offers the only realistic prospect of eradication, thereby reducing damaging ecological impacts and long term management costs.     

Benefits and challenges of maintaining national plant pest lists: an analysis of agricultural pests in Bhutan

Developing and maintaining national plant pest lists helps fulfil international obligations for trading countries, and also provides a foundation for national biosecurity systems. However, if done, lists and analyses are rarely made publically available. We compiled a national plant pest list for Bhutan, a relatively small but agriculturally diverse country for which plant protection is a recent discipline. We treated this pest list as a case study to test the benefits and challenges of maintaining such lists. Six hundred and forty‐five pest species were recorded across 64 different crops. Of those, only 17.0% were listed for Bhutan in the widely used CABI Crop Protection Compendium. Most species (86.4%) were first recorded during the initial discovery phase (1985–88) of a long‐running European Community funded aid programme. Regular taxonomic changes means keeping pest lists up to date requires both effort and expertise (27.0% of the 407 species identified by 1988 have since undergone name changes). Confidence in taxonomic identifications reduced drastically as access to international expertise decreased, from about 69.1% of species being identified with high confidence prior to 1988 to 8.1% afterwards. Many recent records lacked reference material, and voucher specimens for older material are mostly located internationally, making any revision challenging. Of the best represented taxa, greatest taxonomic uncertainty was for nematodes and viruses. Similar patterns were evident for the 112 damaging pest species, defined as those that at least occasionally and locally cause significant losses or require management actions within Bhutan. Of the damaging pests identified to species, all but one was also recorded in India, Bhutan's most important trading partner, and only 16 were restricted to Asia. New damaging pests continue to be recorded, but only five species may represent new incursions since 1988. National pest lists are critical, but to be of greatest value they need to capture taxonomic uncertainty, and focus on pests of greatest significance. For most countries, the development, maintenance and use of a national plant pest list will require ongoing regional and global cooperation to overcome taxonomic impediments, and to maximise the benefits of such lists in terms of facilitating trade and guiding domestic biosecurity activities.     

Clonal plants and plant species diversity in wetland ecosystems in China

Abstract. Clonal plants play important roles in maintaining wetland ecosystems in China. By analysing 108 wetland quadrats distributed throughout China, we evaluated (1) the importance of clonal growth forms in different Chinese wetlands, (2) how the abundance of clonal plants is related to climatic and geographical conditions, and (3) how plant species diversity is related to the abundance of clonal plants. Significant differences in clonal plant importance values were found between different regions of China. Clonal plants were more important in wetland ecosystems located towards the West and North and at higher elevations and, accordingly, experiencing a colder and drier climate. Plant species diversity showed a significant inverse correlation with the importance value of ‘guerilla’‐type plants in most of the wetland regions. However, we found no significant correlation between plant species diversity and importance values of ‘phalanx’‐type plants. In most Chinese wetlands, plant species diversity decreased with increasing importance of guerilla plants and also with an increase of the entire guild of clonal plants. In wetlands with low species richness, however, plant species diversity increased with increasing importance of guerilla plants and of all clonal plants together, suggesting that in these disturbed habitats clonal growth may facilitate the establishment of other, non‐clonal wetland plants.     

Symbiosis as the way of eukaryotic life: The dependent co-origination of the body

Molecular analyses of symbiotic relationships are challenging our biological definitions of individuality and supplanting them with a new notion of normal part–whole relationships. This new notion is that of a ‘holobiont’, a consortium of organisms that becomes a functionally integrated ‘whole’. This holobiont includes the zoological organism (the ‘animal’) as well as its persistent microbial symbionts. This new individuality is seen on anatomical and physiological levels, where a diversity of symbionts form a new ‘organ system’ within the zoological organism and become integrated into its metabolism and development. Moreover, as in normal development, there are reciprocal interactions between the ‘host’ organism and its symbionts that alter gene expression in both sets of cells. The immune system, instead of being seen as functioning solely to keep microbes out of the body, is also found to develop, in part, in dialogue with symbionts. Moreover, the immune system is actively involved in the colonization of the zoological organism, functioning as a mechanism for integrating microbes into the animal-cell community. Symbionts have also been found to constitute a second mode of genetic inheritance, providing selectable genetic variation for natural selection. We develop, grow and evolve as multi-genomic consortia/teams/ecosystems.     

Light partitioning among species and species replacement in early successional grasslands

Abstract. We studied canopy structure, shoot architecture and light harvesting efficiencies of the species (photon flux captured per unit above‐ground plant mass) in a series of exclosures of different age (up to 4.5 yr) in originally heavily grazed grassland in N Japan.Vegetation height and Leaf Area Index (LAI) increased in the series and Zoysia japonica, the dominant in the beginning, was replaced by the much taller Miscanthus sinensis. We showed how this displacement in dominance can be explained by inherent constraints on the above‐ground architecture of these two species. In all stands light capture of plants increased with their above‐ground biomass but taller species were not necessarily more efficient in light harvesting. Some subordinate species grew disproportionally large leaf areas and persisted in the shady undergrowth. Some other species first grew taller and managed to stay in the better‐lit parts of the canopy, but ultimately failed to match the height growth of their neighbours in this early successional series. Their light harvesting efficiencies declined and this probably led to their exclusion. By contrast, species that maintained their position high in the canopy managed to persist in the vegetation despite their relatively low light harvesting efficiencies. In the tallest stands ‘later successional’ species had higher light harvesting efficiencies for the same plant height than ‘early successional’ species which was mostly the result of the greater area to mass ratio (specific leaf area, SLA) of their leaves. This shows how plant stature, plasticity in above‐ground biomass partitioning, and architectural constraints determine the ability of plants to efficiently capture light, which helps to explain species replacement in this early successional series.     

在转基因植物中利用植物凝集素防治害虫的研究

植物凝集素对包括同翅目在内的害虫具有有效抗性。本文就同翅目害虫的危害性、植物凝集素定义的不断深入认识、植物凝集素在植物体内的生理作用、对害虫的作用机理、并对人工饲喂害虫实验及转凝集素的抗虫基因工程研究进展、存在总是等方面作一阐述。     

Budding biology teachers: what have botanical gardens got to offer inquiry learning

Teachers conceptualise inquiry learning in science learning differently. This is particularly evident when teachers are introduced to inquiry pedagogy within a new context. This exploratory study draws on semi-structured interviews conducted with eight pre-service secondary biology teachers following a day visit with university tutors to the Royal Botanical Gardens, Kew. Emerging findings were: first, pre-service biology teachers’ views of inquiry learning range in sophistication from simple notions of ‘learning from doing’ to complex multi-notions such as student generated questions, developing curiosity and encouraging authentic scientific practices. Second, similarly their views of inquiry learning opportunities in botanical gardens ranged from simply places that offered ‘memorable experiences’ to enabling autonomous learning due to the organism diversity and multiple climates. Pre-service teachers categorised as having unsophisticated views of inquiry learning had limited expectations of botanical gardens as productive learning environments. Third, the majority of pre-service teachers were concerned about managing inquiry learning. A tension was identified between how open-ended an inquiry activity could be whilst ensuring student focus. Further, participants were concerned about the practical management of inquiry learning. We discuss implications for teacher educators and botanical garden educators and the requirement for curriculum development and promotion.     

Mapping malaria risk in Africa: What can satellite data contribute?

Recent developments in the access of remotely sensed vegetation and weather data, and their analysis along with other data sources within a geographical information system (GIS), have opened up new possibilities for African health services and research institutes in malaria stratification, monitoring and early warning. Madeleine Thomson, Stephen Connor, Paul Milligan and Stephane Flasse review the current situation and outline the way ahead.     

Southern Hemisphere biodiversity and global change: Data gaps and strategies

Long‐term datasets needed to detect the impacts of global change on southern biodiversity are still scarce and often incomplete, challenging adaptation planning and conservation management. Biological data are probably most limited in arid countries and from the oceans, where natural environmental variability (‘noise’) means that long time series are required to detect the ‘signal’ of directional change. Significant national and international investment and collaboration are needed for most southern nations to reliably track biodiversity trends and improve conservation adaptation to rapid climate change. Emerging early warning systems for biodiversity, incorporating regional environmental change drivers, citizen science and regional partnerships, can all help to compensate for existing information gaps and contribute to adaptation planning.     

Most soil trophic guilds increase plant growth: a meta‐analytical review

Trophic cascades are important drivers of plant and animal abundances in aquatic and aboveground systems, but in soils trophic cascades have been thought to be of limited importance due to omnivory and other factors. Here we use a meta‐analysis of 215 studies with 1526 experiments that measured plant growth responses to additions or removals of soil organisms to test how different soil trophic levels affect plant growth. Consistent with the trophic cascade hypothesis, we found that herbivores and plant pathogens (henceforth pests) decreased plant growth and that predators of pests increased plant growth. The magnitude of this trophic cascade was similar to that reported for aboveground systems. In contrast, we did not find evidence for trophic cascades in decomposer‐ and symbiont‐based (henceforth mutualist) food chains. In these food chains, mutualists increased plant growth and predators of mutualists also increased plant growth, presumably by increasing nutrient cycling rates. Therefore, mutualists, predators of mutualists and predators of pests all increased plant growth. Further, experiments that added multiple organisms from different trophic levels also increased plant growth. As a result, across the dataset, soil organisms increased plant growth 29% and non‐pest soil organisms increased plant growth 46%. Omnivory has traditionally been thought to confound soil trophic dynamics, but here we suggest that omnivory allows for a simplified perspective of soil food webs – one in which most soil organisms increase plant growth by preying on pests or increasing nutrient cycling rates. An implication of this perspective is that processes that decrease soil organism abundance (e.g. soil tillage) are likely to decrease aboveground productivity. Synthesis Soil foodwebs have resisted generalizations due to their diversity and interconnectedness. Here we use results from a meta‐analysis to inform a simplified perspective of soil foodwebs: one in which most soil trophic guilds increase plant growth. Our review also includes the first widespread support for the presence of trophic cascades in soils.     

Plant derived therapeutics for the treatment of Leishmaniasis

Diseases caused by insect borne trypanosomatid parasites are significant, yet remain a neglected public health problem. Leishmania, a unicellular protozoan parasite is the causative organism of Leishmaniasis and is transmitted by female phlebotamine sandflies affecting millions of people worldwide. In the wake of resistance to pentavalent antimonial drugs, new therapeutic alternatives are desirable. The plant kingdom has in the past provided several affordable compounds and this review aims to provide an overview of the current status of available leishmanicidal plant derived compounds that are effective singly or in combination with conventional anti-leishmanial drugs, yet are non toxic to mammalian host cells. Furthermore, delineation of the contributory biochemical mechanisms involved in mediating their effect would help develop new chemotherapeutic approaches.     

相生植保与农林害虫控制

为了适应农林业可持续发展的要求,有害生物的治理措施应强调持久性、稳定性、协调性和可行性。为此,作者提出一种有害生物治理的新途径,就是利用相生植物调节目标保护植物周围环境中生物因素之间的相互关系的一种策略,即：“相生植保”。相生植保,就是充分利用生态系统中固有的动物、植物、微生物之间相互依存的自然规律,通过对环境中其它植物或相关因素的适当调节,达到一种植物的最大生产量,同时又不对另外的生物及周围环境造成伤害。在未来植保学的发展中,相生植保有可能成为一种方向和体系。     

Short review of selected fish biomarkers of xenobiotic exposure with an example using fish hepatic mixed-function oxidase

Abstract One group of biological tools that are useful for monitoring exposure to xenobiotics (and hence water quality) have been collectively referred to as biomarkers and are denned in this paper as any biochemical, histological and/or physiological alterations or manifestations of stress. Biomarkers within an aquatic toxicological context generally represent biological responses of individual organisms to xenobiotic exposure (i. e. responses at the whole organism level of biological organization). These include among others, enzyme alterations, bile metabolites, RNA/DNA ratio, adenylate energy charge, skeletal abnormalities, immune dysfunction, behavioural changes and histopathological lesions. Biomarkers can act as effective early warning sentinels to ensure the protection of the integrity of whole ecosystems, including freshwater and marine ecosystems. This paper briefly reviews a selection of fish biomarkers of xenobiotic chemical exposure and discusses their respective strengths and limitations for use in biomonitoring. An example of the application of fish mixed-function oxidase (MFO) and cytochrome P-450 as biomarkers of chemical exposure in Port Phillip Bay is provided. It is concluded that judicious application of biomarkers such as MFO in association with an understanding of the underlying causal mechanisms of induction and toxicity, will contribute to the successful prediction of biological effects of xenobiotic exposure on fish population health.