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Recent advances in remote sensed imagery and geospatial image processing using unmanned aerial vehicles (UAVs) have enabled the rapid and ongoing development of monitoring tools for crop management and the detection/surveillance of insect pests. This paper describes a (UAV) remote sensing-based methodology to increase the efficiency of existing surveillance practices (human inspectors and insect traps) for detecting pest infestations (e.g., grape phylloxera in vineyards). The methodology uses a UAV integrated with advanced digital hyperspectral, multispectral, and RGB sensors. We implemented the methodology for the development of a predictive model for phylloxera detection. In this method, we explore the combination of airborne RGB, multispectral, and hyperspectral imagery with ground-based data at two separate time periods and under different levels of phylloxera infestation. We describe the technology used—the sensors, the UAV, and the flight operations—the processing workflow of the datasets from each imagery type, and the methods for combining multiple airborne with ground-based datasets. Finally, we present relevant results of correlation between the different processed datasets. The objective of this research is to develop a novel methodology for collecting, processing, analising and integrating multispectral, hyperspectral, ground and spatial data to remote sense different variables in different applications, such as, in this case, plant pest surveillance. The development of such methodology would provide researchers, agronomists, and UAV practitioners reliable data collection protocols and methods to achieve faster processing techniques and integrate multiple sources of data in diverse remote sensing applications.

Grape Phylloxera, Daktulosphaira vitifoliae, is a gall-forming insect that feeds on the leaves and roots of many Vitis species. The roots of the cultivated V. vinifera cultivars and hybrids are highly susceptible to grape phylloxera feeding damage. The native range of this insect covers most of North America, and it is particularly abundant in the eastern and central United States. Phylloxera was introduced from North America to almost all grape-growing regions across five of the temperate zone continents. It devastated vineyards in each of these regions causing large-scale disruptions to grape growers, wine makers and national economies. In order to understand the population diversity of grape phylloxera in its native range, more than 500 samples from 19 States and 34 samples from the introduced range (northern California, Europe and South America) were genotyped with 32 simple sequence repeat markers. STRUCTURE, a model based clustering method identified five populations within these samples. The five populations were confirmed by a neighbor-joining tree and principal coordinate analysis (PCoA). These populations were distinguished by their Vitis species hosts and their geographic locations. Samples collected from California, Europe and South America traced back to phylloxera sampled in the northeastern United States on V. riparia, with some influence from phylloxera collected along the Atlantic Coast and Central Plains on V. vulpina. Reproductive statistics conclusively confirmed that sexual reproduction is common in the native range and is combined with cyclical parthenogenesis. Native grape phylloxera populations were identified to be under Hardy-Weinberg equilibrium. The identification of admixed samples between many of these populations indicates that shared environments facilitate sexual reproduction between different host associated populations to create new genotypes of phylloxera. This study also found that assortative mating might occur across the sympatric range of the V. vulpina west and V. cinerea populations.

The phylloxera Daktulosphaira vitifoliae (Fitch 1856) (Hemiptera; Phylloxeridae) is one of the main pests of grapevines, feeding on the leaves and roots. In Brazil, the presence of winter eggs has been identified on branches of the ‘Paulsen 1103’ rootstock, which could be a source of leaf and root infesting forms during vegetative phase. This study evaluated alternatives for controlling ‘winter eggs’ in potted cuttings of the ‘Paulsen 1103’ rootstock and evaluate the effect of bioinsecticides and insecticides on the root-galling form in the laboratory. In this study, it was found that heat treatment at 50 °C for 30 min resulted in no galls forming on the leaves (100% mortality of winter eggs). Similar results were obtained using standard insecticides Imidacloprid (Provado® 200 SC) and Flupyradifurone (Sivanto® Prime 200 SL). In treatments in which the cuttings were subjected to the sodium hypochlorite, leaf galls were formed (average of 1.5 gall). The commercial products Meta-Turbo® SC, Metarril® WP E9, Bovéria-Turbo®, FlyControl® WP and Octane®, resulted in low root-galling form mortality at 15 days after application (<16% mortality). Meanwhile, the garlic-based plant extract Eco Tirano® caused 72.6% mortality, which was similar to standard insecticides Provado® 200 SC and Sivanto® Prime 200 SL. Based on the results, heat treatment is an alternative for controlling winter eggs in the process of forming grapevine seedlings and the plant extract-based Eco Tirano® and the Provado® 200 SC and Sivanto® Prime 200 SL are potential insecticides for reducing infestations of the root-galling form of phylloxera in grapevine cultivation. RESUMO: A filoxera Daktulosphaira vitifoliae (Fitch 1856) (Hemiptera: Phylloxeridae) é uma das principais pragas da videira, alimentandose nas folhas e raízes. No Brasil, a presença de ovos de inverno foi identificada em ramos do porta-enxerto ‘Paulsen 1103’ podendo ser uma fonte de formas infestantes de folhas e raízes durante a fase vegetativa. Este estudo teve como objetivo avaliar alternativas de controle de ovos de inverno em estacas lenhosas do porta-enxerto ‘Paulsen 1103’ e avaliar o efeito de bioinseticidas e inseticidas sobre a forma radícola em laboratório. No presente estudo, foi verificado que o tratamento térmico a 50 °C por 30 min resultou na não formação de galhas nas folhas (mortalidade de 100% dos ovos de inverno). Resultados semelhantes foram Imidacloprido (Provado® 200 SC) e Flupiradifurrona (Sivanto® Prime 200 SL). Nos tratamentos em que as estacas foram submetidas à Câmara fria (2 a 4 °C por 50 dias) e Câmara fria (2 a 4 °C por 50 dias + Hipoclorito de sódio) houve formação de galhas nas folhas (média de 1,5 galha). Os produtos comerciais Meta-Turbo® SC, Metarril® WP E9, Bovéria-Turbo®, FlyControl® WP e Octane®, resultaram em baixa mortalidade da forma radícola aos 15 dias após a aplicação (<16% de mortalidade). Por sua vez, o extrato de plantas à base de alho Eco Tirano® causou 72,6% de mortalidade, sendo similar aos inseticidas Provado® 200 SC e Sivanto® Prime 200 SL. Com base nos resultados, o tratamento térmico é uma alternativa para o controle dos ovos de inverno no processo de formação de mudas de videira o extrato de plantas Eco Tirano® e os inseticidas Provado® 200 SC e Sivanto® Prime 200 SL são potenciais inseticidas para proporcionar a redução das infestações da forma radícola da filoxera na cultura da videira.

Grape phylloxera, Daktulosphaira vitifoliae (Fitch), is an economically significant pest of grapevines. Identification of phylloxera genotypes is an important aspect of management as genotypes differ in virulence and susceptibility to control using resistant rootstocks. Microsatellite markers developed on polyacrylamide gel systems have been the most widely used molecular method for phylloxera genotype identification, but this approach has been superseded by fluorescent capillary-based genotyping. The current study presents new laboratory methods for amplifying a standard set of eight phylloxera microsatellite markers using PCR-incorporated fluorescently labelled primers, genotyped on an ABI capillary platform. Comparison of allele size data scored on (i) polyacrylamide, (ii) capillary, and (iii) high-throughput sequencing (HTS) platforms revealed that the capillary genotyping most closely matched the HTS allele sizes, while alleles of loci originally scored on a polyacrylamide platform differ in size by up to three base pairs, mostly due to the presence of previously uncharacterised DNA sequence indels. Seven common clonal lineages of phylloxera known from Australia are proposed as reference samples for use in calibrating genotyping systems between platforms and laboratories to ensure universal scoring of allele sizes, providing a critical link for accurately matching previous phylloxera genotype studies with current research.

Grapevine phylloxera Daktulosphaira vitifoliae Fitch (Hemiptera: Phylloxeridae) has been present in Australia for almost 150 years but has not spread to south‐west Western Australia, in part due to the relative isolation of the region. Recent improvements in tourist access, with interstate flights now arriving at Busselton Margaret River Airport, raise concerns about potential phylloxera introductions via wine tourism. In this paper, we simulate the potential economic impact on the Western Australian winegrape industry following a hypothetical arrival event in the Margaret River wine region. We use soil texture maps to assess the suitability of winegrape‐growing areas to phylloxera establishment and construct a model to predict the likely cost and revenue implications of replanting vines to resistant rootstock as they become infested. Our results suggest that if strict quarantine measures to limit spread are not implemented, a phylloxera incursion could affect 60%–70% of vines and cause cumulative losses of AUD150–290 million over a 50‐year period. This is equivalent to a 3%–6% annual contraction of winegrape production.

Key messageThe maternal and paternal parentage of 36 rootstocks was determined and verified. The results of this study indicate that existing grape rootstocks are closely related to each other and have a narrow genetic background.Rootstocks are used to protect grapevines from biotic and abiotic stresses including phylloxera, nematodes, viruses, limestone-based soils, salinity and drought. The most important rootstocks were developed from three grape species between the 1890s and the 1930s in European breeding programs. In this report, we developed nuclear and chloroplast SSR fingerprint data from rootstock selections maintained in germplasm collections, compared them to develop a reference dataset, and carried out parentage analysis to resolve previously reported, and determine new, breeding records. We refined and updated the parentage of 26 rootstocks based on 21 nuclear and 14 chloroplast markers. Results indicate that 39% of the genetic background of analyzed rootstocks originated from only three accessions of three grape species: Vitis berlandieri cv. Rességuier 2, V. rupestris cv. du Lot and V. riparia cv. Gloire de Montpellier. Results determined that Rességuier 2 is the maternal parent for 14 commercial rootstocks, 9 of which are full-sibs with Gloire de Montpellier as the paternal parent. Similarly, du Lot is the paternal parent of nine rootstocks. The pedigree information for 28 rootstocks was determined or corrected in this study. The previously reported pedigree information for eight of the rootstocks was correct. The results found that the world’s existing rootstocks have a narrow genetic base derived from only a few American grape species. Future rootstock breeding efforts should use a more diverse array of species to combat a changing climate and pest pressure.

Endoparasitism by gall-forming insects dramatically alters the plant phenotype by altering growth patterns and modifying plant organs in ways that appear to directly benefit the gall former. Because these morphological and physiological changes are linked to the presence of the insect, the induced phenotype is said to function as an extension of the parasite, albeit by unknown mechanisms. Here we report the gall-forming aphid-like parasite phylloxera, Daktulosphaira vitifoliae, induces stomata on the adaxial surface of grape leaves where stomata typically do not occur. We characterized the function of the phylloxera-induced stomata by tracing transport of assimilated carbon. Because induction of stomata suggests a significant manipulation of primary metabolism, we also characterized the gall transcriptome to infer the level of global reconfiguration of primary metabolism and the subsequent changes in downstream secondary metabolism. Phylloxera feeding induced stomata formation in proximity to the insect and promoted the assimilation and importation of carbon into the gall. Gene expression related to water, nutrient, and mineral transport; glycolysis; and fermentation increased in leaf-gall tissues. This shift from an autotrophic to a heterotrophic profile occurred concurrently with decreased gene expression for nonmevalonate and terpenoid synthesis and increased gene expression in shikimate and phenylpropanoid biosynthesis, secondary metabolite systems that alter defense status in grapes. These functional insect-induced stomata thus comprise part of an extended phenotype, whereby D. vitifoliae globally reprograms grape leaf development to alter patterns of primary metabolism, nutrient mobilization, and defense investment in favor of the galling habit.

Background Grafting is an intensive commercial practice required to protect the European grapevine against the Phylloxera pest. Rootstocks resistant to this pest are hybrids of American vine species with different levels of compatibility with European Vitis vinifera varieties. Aiming to understand what drives grafting compatibility in grapevine, a transcriptomic approach was used to search for master regulators of graft success. Two scion/rootstock combinations, with different levels of compatibility, were compared in a nursery-grafting context at two stages, at 21 and 80 days after grafting. Results In the most compatible combination, an earlier and higher expression of genes signaling the metabolic and hormonal pathways as well as a reduced expression of genes of the phenolic metabolism and of the oxidative stress response was observed. At 80 days after grafting a higher expression of transcription factors regulating vascular maintenance, differentiation and proliferation was obtained in the most compatible combination. Moreover, lower expression levels of microRNAs potentially targeting important transcription factors related to plant development was observed in the more compatible combination when compared to the less compatible one. Conclusion In this context, a set of regulators was selected as potential expression markers for early prediction of a compatible grafting.

Fertilizers generally influence the nutritional quality or defense ability of the plants, which can indirectly cause an increase in populations of herbivorous insect pests such as grape phylloxera, Daktulosphaira vitifoliae (Homoptera: Phylloxeridae, Fitch). The effects of nutrient solutions on grape–grape phylloxera interactions were analyzed using five concentrations (nitrogen content: 15, 30, 60, 120, and 180 mg/L) of Hoagland's nutrient solution to irrigateVitis vinifera L. ×Vitis labrusca L. (Kyoho). Life table variables and life history variables showed a hump-shaped or an inverted hump-shaped curve as nutrient input level increased. Sixty micro-gram per liter treatment resulted in the greatest longevity and egg incubation, shortened the nymph duration and significantly increased the adult lifespan. Overall, both excessive and insufficient nutrient inputs curbed growth and multiplication of D. vitifoliae.These results provide a theoretical basis for vineyards for amending fertilizer inputs to prioritize the prevention and control of this pest. Graphical Abstract

AimEurasian grapevine (Vitis vinifera), one of the most important fruit crops worldwide, diverged from its wild and currently endangered relative (V. vinifera ssp. sylvestris) about 11,000 years ago. In the 19th century, detrimental phylloxera and disease outbreaks in Europe forced grapevine cultivation to use American Vitis species as rootstocks, which have now become naturalized in Europe and are starting to colonize similar habitats to the wild grapevine. Accordingly, wild grapevine now faces two additional threats: the expansion of vineyards and invasive rootstocks. Furthermore, climate change is expected to have significant impacts on the distribution of all grapevines in Europe. In this study, we quantified the distributional and bioclimatic overlap between grapewine's wild relative and the taxa associated with viticulture, under current and future climate.LocationEurope, North America.MethodsThe distributions of wild Eurasian grapevine, cultivated Eurasian grapevine and five American grapevine species used in rootstock breeding programs were linked to climate variables to model their bioclimatic niches. These ecological niche models were used to quantify the spatial and bioclimatic overlap between these seven Vitis taxa in Europe.ResultsNiche and spatial overlap is high between the wild, cultivated and rootstock grapevines, suggesting that existing conflicts between vineyards and wild grapevine conservation may be further complicated by naturalized rootstocks outcompeting the wild grapevine, especially under future scenarios of climate change. In the hottest scenario, only 76.1% of the current distribution of the Eurasian grapevine remains in suitable area.Main ConclusionsAs wild grapevine may ultimately provide a valuable gene pool for adapting viticulture to a changing world, these findings demonstrate the need for improved management of the wild grapevine and its natural habitat, to counteract the harmful effects of global change on the wild relatives of viticulture.