Plant Phytopathology

Sweet corn, silage and grain crops have been facing the threat of severe corn disease for many years, spreading to various parts of Israel. Over the past few years, we conducted a series of field experiments, with the assistance of Netafim Israel, growers' associations and farmers from the Galilee region. In 2017-2018, this research led to a historic breakthrough: for the first time, 60 years since its discovery, an economically feasible solution was found for late wilt disease of corn in Israel. The successful treatment protocol is based on changing the cultivation method, changing the traditional irrigation method used in most corn growing areas in Israel, and the sophisticated integration of pesticide mixtures in a schedule adapted to key points in the development of the disease. This method can now be widely applied in commercial fields for the protection of sensitive corn varieties.

Late wilt disease in corn is caused by the fungus Harpophora maydis, which is found in the soil and seeds. It penetrates the plant and blocks the water supply to its upper parts. The disease, considered to be the most severe corn disease in our region, was first discovered in Egypt in 1960, where it still persists and causes serious damage. The disease is now reported in 11 countries. In Israel, it has existed for 40 years in the Upper Galilee, especially in the Hula Valley, and in the past decade, has spread to the south of the country. In heavily contaminated fields and in sensitive maize cultivars, the pathogen can cause 100% infection and total yield loss. The disease is characterized by a rapid wilt of the corn plant, which usually occurs two to three weeks before harvesting. In the past, attempts had been made to control the pathogen using different methods, including agricultural (balanced soil fertility and flood fallowing), chemical, biological, physical (solar heating) and plant compounds. Despite the potential of some of these methods, the only means applied in Israel to date to restrict the disease is the use of resistant corn varieties. However, in Egypt and Spain, virulent pathogen strains that threaten resistant maize cultivars have been found.

The research team led by Dr. Ofir Degani from Migal – The Galilee Research Institute and Tel-Hai College, funded and supported by Netafim Israel, the Extension Service of the Israel Ministry of Agriculture and Rural Development, and growers' associations, has recently led to a breakthrough development of historical significance. For the first time, 60 years since the discovery of the late wilt disease, an efficient and economically feasible solution has been found that can be used on a large scale to protect sensitive corn varieties in commercial fields.

This solution, published in December 2018 in the leading scientific journal PloS ONE, saves about 40% of irrigation costs and combines antifungal mixtures with different mechanisms to prevent resistance development. The new application was tested in field trials in 2017-2018 and included the injection to the irrigation system of  the substances Difenoconazole + Azoxystrobin (of which the commercial name is 'Ortiva-Top', manufactured by Syngenta, Basel ,Switzerland, supplied by Adama Makhteshim, Airport City, Israel), at intervals of 15, 30 and 45 days from sowing, or other fungicide mixtures. Savings in the deployment of irrigation lines was acquired by using a dripline for two adjacent rows (a row spacing of 50 cm instead of 96 cm), a row space that maintains the effective concentration of the fungicide in the soil. A recently developed real-time PCR-based molecular detection system showed that following the treatment of 'Ortiva-Top', the amount of pathogen DNA in the host tissue decreased to near zero levels. The successful treatments using 'Ortiva-Top' resulted in a 100% decrease in dehydration symptoms and a 100% increase in crop yield, together with an approximately 40% increase in crop quality (the yield classified as A class that had a cob weight exceeding 250 g). These results were also obtained in an alternative protocol– the replacement of pesticides based on 'Ortiva-Top' in the first application and the application of pesticides harboring a different mechanism of action in the second and third applications. A remote sensing evaluation of the efficacy of the treatments using a quadcopter equipped with a thermal infra-red sensitive camera carried out by Dr. Assaf Chen’s research team (Migal - Galilee Research Institute) supported the results and showed its effectiveness as a research tool for diagnosing infected fields.

These results are the fruits of a decade of research (since 2008), in which a fundamental understanding of the pathogen H. maydis and the generation and development of late wilt disease in Israel was established. During this period, new research methods such as sensitive molecular tests (PCR and qPCR) were developed in order to diagnose fungal virulence and in order to detect the pathogen inside the host plant tissue. In addition, a link was found to plant hormones that regulate the development of the pathogen. Complex field trials that were carried out annually over a full growing season (about 80 days) since 2009 led to this important discovery.
However, the work on late wilt disease does not end here. In the past two years, Dr. Degani's research team identified the presence of H. maydis in secondary hosts, such as cotton, watermelon and green foxtail (Setaria viridis), which could support the survival of the pathogen, developed an environmentally friendly biological control method to control the pathogen, and established a new bio-assay for examining soils suspected of being infected with the pathogen. These new findings, which are currently in the process of being prepared for scientific publication, are encouraging the continuation and enhancement of the research.

Cephalosporium maydis is a destructive microbial pathogen for the economic important crop maize in Egypt causing the late wilt disease. As pathogenesis is host and pathogen dependent, the effect of maize root exudates on C. maydis linear growth and the role of the fungal metabolites in the pathogenesis on maize were investigated. The obtained results revealed that root exudates of the resistant maize cultivar SC10 decreased the linear growth of C. maydis in Petri-dishes while those of the susceptible cultivar Balady had no effect. In addition to the known role of vessels plugging by the fungal biomass, responsibility of the fungal metabolites in pathogenesis was proved since the tested filtrates of C. maydis had deleterious effects on grain-germination, seedling growth and water conductivity in shoot parts. Injection of mature maize plants with C. maydis filtrates caused internal darkbrown to black discoloration.

Sunflower downy mildew (Plasmopara halstedii) is one of the major diseases that can be controlled by using resistant cultivars and seed dressings; however, several isolates have developed tolerance to some fungicides and the resistance has also been overcome by new pathotypes. We aimed to examine the pathotype distribution in Hungary and to test the pathotypes' mefenoxam sensitivity. The isolates, which provided the basis of the research were collected from different regions of Hungary between 2014 and 2017 and, later, their pathotypes were identified. According to our results, pathotype 704 was one of the most widespread in Hungary, but pathotype 730, pathotype 724 and pathotype 700 were also detected. Seven out of ten isolates caused relatively high disease rates on the mefenoxam-treated and inoculated sunflower plants with P. halstedii. The pathogen has a high genetic variability which enhances the possibility to develop fungicide resistance. Furthermore, this variability can easily contribute to the breakdown of the resistant genes of the resistant hybrids. Both features can reduce the effectiveness of management; therefore, the continuous monitoring of this oomycete is very important.

Background. Reliable genotyping that provides an accurate description of diversity in the context of pathogen emergence is required for the establishment of strategies to improve disease management. MultiLocus variable number tandem repeat analysis (MLVA) is a valuable genotyping method. It can be performed at small evolutionary scales where high discriminatory power is needed. Strains of the Ralstonia solanacearum species complex (RSSC) are highly genetically diverse. These destructive pathogens are the causative agent of bacterial wilt on an unusually broad range of host plants worldwide. In this study, we developed an MLVA scheme for genotyping the African RSSC phylotype III. Methods. We selected different publicly available tandem repeat (TR) loci and additional TR loci from the genome of strain CMR15 as markers. Based on these loci, a new phylotype III-MLVA scheme is presented. MLVA and multiLocus sequence typing (MLST) were compared at the global, regional, and local scales. Different populations of epidemiologically related and unrelated RSSC phylotype III strains were used. Results and Discussion. Sixteen polymorphic TR loci, which included seven mi-crosatellites and nine minisatellites, were selected. These TR loci were distributed throughout the genome (chromosome and megaplasmid) and located in both coding and intergenic regions. The newly developed RS3-MLVA16 scheme was more dis-criminative than MLST. RS3-MLVA16 showed good ability in differentiating strains at global, regional, and local scales, and it especially highlighted epidemiological links between closely related strains at the local scale. RS3-MLVA16 also underlines genetic variability within the same MLST-type and clonal complex, and gives a first overview of population structure. Overall, RS3-MLVA16 is a promising genotyping method for outbreak investigation at a fine scale, and it could be used for outbreak investigation as a first-line, low-cost assay for the routine screening of RSSC phylotype III.

Cochliobolus heterostrophus is an agriculturally important and emerging model pathogen for studying the signalling hierarchy’s role during maize colonization. In particular, G-protein and MAPK-linked pathways play a major role during pathogenesis. Although gene disruption studies are an efficient method for identifying the role of these cascades, differentiating between the mutant strains’ virulence ability may become an intricate task. For example, in C. heterostrophus, mutants in a G-protein α subunit gene, cga1, are defective in mating and appressorium formation, but unlike mutants in homologous genes in other fungal pathogens, cga1 mutants remained highly virulent to corn under some host physiological conditions. Here, we used the cga1 strain as a model for developing an in vivo sensitive and accurate pathogenicity assay. A detailed and well-controlled analysis of wild-type (WT) and cga1 pathogenic behavior revealed that detached leaves are significantly more vulnerable to the disease than intact ones. In intact leaves, cga1 mutants were less infective of maize under most conditions. This difference was maximized when the first seedling leaf was chosen for inoculation and when the infected leaves, with spores or mycelia fragments droplets, were incubated for a period of four days. This optimal condition set enabled us to classify the C. heterostrophus G-protein signalling mutants (deficient in α, β or both subunits) in order of decreasing virulence: WT > cga1 > cgb1 > cga1 cgb1. The method presented here proves to be accurate and sensitive enough to identify even slight variations in virulence. Moreover, it could be modified for use in the studies of other foliar phytoparasitic fungi.

Two neem-derived pesticides were examined under in vitro and in vivo conditions to test their efficacy in controlling Plasmopara halstedii pathotype 704, a causal agent of downy mildew in sunflower. All the tested concentrations of neem leaf extract and the highest concentration of commercial neem product significantly reduced the sporangial germination under in vitro conditions. In in vivo experiment, 3-days old pre-treated seedlings with both concentrations of neem leaf extract and the highest concentration of commercial product showed a significant reduction in the infection indicating possible systemic effect of neem. When the seedlings were treated following the infection with P. halstedii (i.e., post-treatment), only the highest concentrations of neem leaf extract and the commercial product showed a significant reduction in the infection indicating curative effect of neem. Possibilities for the control of P. halstedii with neem-derived pesticides are discussed.

The cultivation of sugarcane represents an important part in the Colombian economy due to the diverse applications in industries like liquor, food, paper and biofuels. Sugarcane worldwide production is affected by the presence of phytopathogenic agents, mainly filamentous fungi such as Physalospora tucumanensis (red rot disease) and Fusarium spp. To date in Colombia, Pokka boheng disease whose causal agent is the fungus Fusarium verticillioides, has not been reported, which is why it is necessary to identify appropriately this microorganism, responsible for losses in productivity and food contamination. In order to isolate and identify the infectious agent from symptomatic tissues, disinfection and culture in liquid and solid culture mediums were performed in malt extract (2%) and yeast extract (0.2%) both liquid and solid, for 7 days. After several replicates in agar plate, a purification was made along with a morphological characterization based on the shape and color of the mycel...

Sunflower downy mildew (Plasmopara halstedii) is one of the major diseases that can be controlled by using resistant cultivars and seed dressings; however, several isolates have developed tolerance to some fungicides and the resistance has also been overcome by new pathotypes. We aimed to examine the pathotype distribution in Hungary and to test the pathotypes' mefenoxam sensitivity. The isolates, which provided the basis of the research were collected from different regions of Hungary between 2014 and 2017 and, later, their pathotypes were identified. According to our results, pathotype 704 was one of the most widespread in Hungary, but pathotype 730, pathotype 724 and pathotype 700 were also detected. Seven out of ten isolates caused relatively high disease rates on the mefenoxam-treated and inoculated sunflower plants with P. halstedii. The pathogen has a high genetic variability which enhances the possibility to develop fungicide resistance. Furthermore, this variability can...

Rice yellow mottle virus (RYMV) causes high losses to rice production in Africa. Several sources of varietal high resistance are available but the emergence of virulent pathotypes that are able to overcome one or two resistance alleles can sometimes occur. Both resistance spectra and viral adaptability have to be taken into account to develop sustainable rice breeding strategies against RYMV. In this study, we extended previous resistance spectrum analyses by testing the rymv1-4 and rymv1-5 alleles that are carried by the rice accessions Tog5438 and Tog5674, respectively, against isolates that are representative of RYMV genetic and pathogenic diversity. Our study revealed a hypervirulent pathotype, named thereafter pathotype T′, that is able to overcome all known sources of high resistance. This pathotype, which is spatially localized in West-Central Africa, appears to be more abundant than previously suspected. To better understand the adaptive processes of pathotype T′, molecular ...

Abstract

Downy mildew of sunflower (Helianthus annuus L.) is caused by Plasmopara halstedii (Farl.) Berl. et de Toni, leading to significant losses in crop production worldwide. The number of new and more aggressive pathotypes has increased rapidly over the last 10 years in Europe (Virányi et al. 2015, Bán et al. 2018), therefore, constantly monitoring the distribution of races is an important task. As part of regular surveys in June 2019, severe downy mildew was identified in some regions, appearing as chlorotic lesions along the veins of the adaxial side and white sporulation on the abaxial side of the leaves of severely stunted hybrids containing PI6 and PI7 resistance genes. The identification of the pathogen was performed microscopically based on morphological characteristics (average size of sporangia: 28x20 µm). Disease incidence (the ratio of diseased plants) ranged between 10 and 30% per field in three regions and resulted in moderate yield loss. Isolates (defined as a lesion per leaf) were collected from 4 to 8 infected leaves of each hybrid by region and stored at -70°C. Two, one and one isolates of P. halstedii were selected and characterized from the southeastern (Békés County), northern (Nógrád County) and northeastern (Borsod-Abaúj-Zemplén County) regions of Hungary, respectively. The pathotype of the four isolates was determined using the international standardized nomenclature method reviewed by Trojanová et al. (2017), including nine sunflower differential inbred lines (HA-304, RHA-265, RHA-274, PMI-3, PM-17, 803-1, HAR-4, QHP2 and HA-335). Zoosporangia from frozen sunflower leaves were washed off into bidistilled water and the concentration was adjusted to 3.5x104 sporangia/ml using a hemocytometer. Three-day-old seedlings with a radical of 1 to 1.5 cm long were immersed in the sporangial suspension and kept at 16°C overnight (Cohen and Sackston 1973). Inoculated seedlings were planted into trays containing clear moistened perlite (d = 4 mm) and grown in a growth chamber with a photoperiod of 12 h. The experiment was carried out twice with each isolate using 15 seeds/differential line with two replicates. Bidistilled water was sprayed on the plants 9 days after inoculation, and then trays were covered with a black polyethylene bag and maintained at 19°C overnight to induce sporulation. The first disease assessment was done based on cotyledons bearing white sporulation. Next, a second evaluation was performed 21 days after inoculation assessing stunting of the plants, chlorotic lesions on true leaves and damping-off. All 4 isolates examined caused disease on differential lines HA-304, RHA-265, RHA-274, PMI-3, PM-17 and HA-335, whereas the other lines showed no symptoms and signs of sunflower downy mildew. As a result, it was concluded that the presence of P. halstedii pathotype 734 was confirmed. This pathotype is likely widespread in Hungary as it could be detected from three different regions. Moreover, the possibility that pathotype 734 is present in Hungary has been raised before (Iwebor et al. 2018). This pathotype is already widespread in the USA and Russia and is considered to be highly aggressive, since it was able to infect hybrids with resistance genes PI6 and PI7 (Iwebor et al. 2018, Spring 2019). To our knowledge, this is the first report of pathotype 734 of P. halstedii in Hungary and Central Europe. Continuous monitoring and incorporation of new resistance genes into sunflower hybrids are essential steps in the future to control P. halstedii.

Sunflower downy mildew (Plasmopara halstedii) is one of the major diseases that can be controlled by using resistant cultivars and seed dressings; however, several isolates have developed tolerance to some fungicides and the resistance has also been overcome by new pathotypes. We aimed to examine the pathotype distribution in Hungary and to test the pathotypes' mefenoxam sensitivity. The isolates, which provided the basis of the research were collected from different regions of Hungary between 2014 and 2017 and, later, their pathotypes were identified. According to our results, pathotype 704 was one of the most widespread in Hungary, but pathotype 730, pathotype 724 and pathotype 700 were also detected. Seven out of ten isolates caused relatively high disease rates on the mefenoxam-treated and inoculated sunflower plants with P. halstedii. The pathogen has a high genetic variability which enhances the possibility to develop fungicide resistance. Furthermore, this variability can...

El cultivo de la caña de azúcar representa una parte importante en la economía de Colombia debido a las diversas aplicaciones en industrias como licor, alimentos, papel y biocombustibles. Su producción en todo el mundo se ve afectada por la presencia de agentes fitopatógenos, principalmente hongos filamentosos como Physalospora tucumanensis (agente causal de la enfermedad “Pudrición roja”) y Fusarium spp. Hasta la fecha, en Colombia, no se ha reportado la enfermedad de Pokka boheng en este cultivo cuyo agente causal es el hongo Fusarium verticillioides, por lo que es necesario identificar adecuadamente este microorganismo, responsable de las pérdidas en productividad y contaminación de los alimentos. Con el fin de aislar e identificar el agente infeccioso de los tejidos sintomáticos, se realizó la desinfección y posterior siembra de éstos en medios de cultivo extracto de malta (2 %) y extracto de levadura (0.2 %) tanto líquido como sólido durante 7 días. A partir de varias placas petri, se realizó la respectiva purificación y una caracterización morfológica basada en la forma y el color del micelio, así como el tipo de esporas generadas. Adicionalmente, el material genético se extrajo y se amplificaron los marcadores genéticos (ITS, factor de elongación 1-α (EF) y β-tubulina (Btub)) por PCR. Luego, se utilizó la secuenciación del ADN para obtener los datos para realizar una reconstrucción filogenética mediante métodos probabilísticos (máxima verosimilitud e inferencia bayesiana). La cepa aislada, nombrada como EA-FP0013 se localizó en el grupo del complejo Fujikuroi, con una alta identidad probable para Fusarium verticillioides. Por lo tanto, la identificación temprana y específica de especie de estos aislados fúngicos, utilizando métodos moleculares, puede permitir el diagnóstico oportuno de enfermedades fisiopatológicas emergentes de interés para la región, y así proponer las estrategias de control respectivas.

Dalbergia sissoo (shisham) seeds naturally infected with Curvularia lunata showed either black discoloration (1.25 to 8.75%) or appeared dull (0.50 to 10.0%). When they were incubated, they yielded pure growth of the pathogen. During location studies, cleared whole mount preparation and component plating revealed the presence of infection restricted to the seed coat and cotyledons of asymptomatic seeds. However, this pathogen penetrates the deeper tissue of symptomatic seeds to the embryonic axis. Due to heavy infection, the disintegration of cells results in the formation of lysogenic cavities. The fungus enters the seeds through the hilar region and epidermal cells of the seed coat to the aleurone layer and finally into the cotyledonary cells of the embryo. The pathogen is both externally and internally seed-borne. The internal inoculum affected seed germination, viability and caused high total (pre-and post-emergence) losses (15 to 80%). The pathogen was transmitted from seed to seedling causing heavy losses to the tree plantation.

Sunflower downy mildew (Plasmopara halstedii) is one of the major diseases that can be controlled by using resistant cultivars and seed dressings; however, several isolates have developed tolerance to some fungicides and the resistance has also been overcome by new pathotypes. We aimed to examine the pathotype distribution in Hungary and to test the pathotypes' mefenoxam sensitivity. The isolates, which provided the basis of the research were collected from different regions of Hungary between 2014 and 2017 and, later, their pathotypes were identified. According to our results, pathotype 704 was one of the most widespread in Hungary, but pathotype 730, pathotype 724 and pathotype 700 were also detected. Seven out of ten isolates caused relatively high disease rates on the mefenoxam-treated and inoculated sunflower plants with P. halstedii. The pathogen has a high genetic variability which enhances the possibility to develop fungicide resistance. Furthermore, this variability can...

Two neem-derived pesticides were examined under in vitro and in vivo conditions to test their efficacy in controlling Plasmopara halstedii pathotype 704, a causal agent of downy mildew in sunflower. All the tested concentrations of neem leaf extract and the highest concentration of commercial neem product significantly reduced the sporangial germination under in vitro conditions. In in vivo experiment, 3-days old pre-treated seedlings with both concentrations of neem leaf extract and the highest concentration of commercial product showed a significant reduction in the infection indicating possible systemic effect of neem. When the seedlings were treated following the infection with P. halstedii (i.e., post-treatment), only the highest concentrations of neem leaf extract and the commercial product showed a significant reduction in the infection indicating curative effect of neem. Possibilities for the control of P. halstedii with neem-derived pesticides are discussed.

Experiment was conducted in the Department of Plant Protection, SHIATS to evaluate the efficacy of Jatropa leaf powder at concentration 1, 2 and 3 % w/w against Alternaria solani inciting the leaf blight of tomato. Pathogen was isolated from the research field of SHIATS and cultured on Potato Dextrose Agar medium. Mass culture of pathogen was carried out in Sorghum grains and soil was sickened it with the mass culture of pathogen @ 40g (4×10 3 /g of soil). The Jatropa leaf powder (JLP) was amended in sickened soil (100g/pot) before 2 days of seed sowing. The tomato seeds were sown in 4 treatments and 5 replications in the fiber cup including control. The symptoms started as yellowing and browning of leaves after 15 days of germination and the symptoms progressed upwards with the growth of plants. Disease incidence and Percentage Disease intensity was checked at regular intervals in 15, 30 and 45 days after germination. The results showed that JLP at all concentration was found to be...

Sunflower downy mildew (Plasmopara halstedii) is one of the major diseases that can be controlled by using resistant cultivars and seed dressings; however, several isolates have developed tolerance to some fungicides and the resistance has also been overcome by new pathotypes. We aimed to examine the pathotype distribution in Hungary and to test the pathotypes' mefenoxam sensitivity. The isolates, which provided the basis of the research were collected from different regions of Hungary between 2014 and 2017 and, later, their pathotypes were identified. According to our results, pathotype 704 was one of the most widespread in Hungary, but pathotype 730, pathotype 724 and pathotype 700 were also detected. Seven out of ten isolates caused relatively high disease rates on the mefenoxam-treated and inoculated sunflower plants with P. halstedii. The pathogen has a high genetic variability which enhances the possibility to develop fungicide resistance. Furthermore, this variability can...

Background.Reliable genotyping that provides an accurate description of diversity in the context of pathogen emergence is required for the establishment of strategies to improve disease management. MultiLocus variable number tandem repeat analysis (MLVA) is a valuable genotyping method. It can be performed at small evolutionary scales where high discriminatory power is needed. Strains of theRalstonia solanacearumspecies complex (RSSC) are highly genetically diverse. These destructive pathogens are the causative agent of bacterial wilt on an unusually broad range of host plants worldwide. In this study, we developed an MLVA scheme for genotyping the African RSSC phylotype III.Methods.We selected different publicly available tandem repeat (TR) loci and additional TR loci from the genome of strain CMR15 as markers. Based on these loci, a new phylotype III-MLVA scheme is presented. MLVA and multiLocus sequence typing (MLST) were compared at the global, regional, and local scales. Differ...

Background. Reliable genotyping that provides an accurate description of diversity in the context of pathogen emergence is required for the establishment of strategies to improve disease management. MultiLocus variable number tandem repeat analysis (MLVA) is a valuable genotyping method. It can be performed at small evolutionary scales where high discriminatory power is needed. Strains of the Ralstonia solanacearum species complex (RSSC) are highly genetically diverse. These destructive pathogens are the causative agent of bacterial wilt on an unusually broad range of host plants worldwide. In this study, we developed an MLVA scheme for genotyping the African RSSC phylotype III. Methods. We selected different publicly available tandem repeat (TR) loci and additional TR loci from the genome of strain CMR15 as markers. Based on these loci, a new phylotype III-MLVA scheme is presented. MLVA and multiLocus sequence typing (MLST) were compared at the global, regional, and local scales. D...

Robotic Tools Towards a New Sustainable and Eco-friendly IPM to Control Flavescence Dorée Disease
Esmeraldina Sousa1*, Tiago Ramalho2, João Gueifão2, Isabel Rodrigues1, Eugénia Andrade1, Margarida Santos1, Pedro Petiz2
1 INIAV-Instituto Nacional de Investigação Agrária e Veterinária. Av. da República, Quinta do Marquês, 2780-157 Oeiras. Portugal.

2 TEKEVER. Rua das Musas, 3.30. 1990-113 Lisboa, Portugal.
*Corresponding authors: esmeraldina.sousa@iniav.pt; tiago.ramalho@tekever.com



INTRODUCTION
Grapevine (Vitis vinifera L.) is one the most economically important crops worldwide due to the high value of the grape and the importance of wine making sector. In Portugal, it plays an essential role on the national economy. Indeed, Portugal was classified as being the 5th largest European producer and the 10th having the largest global wine makers group (IVV*, 2015).

Portugal has a great biodiversity of grapevine cultivars specific to each wine producing areas that have intrinsic, unexplored, differential susceptibilities to the Flavescence dorée disease (FD) (1)(2). A great concern is that many of these cultivars are highly susceptible to the FD, compromising the existing biodiversity.

Flavescence dorée (FD), a quarantine disease in Europe, included in the 2000/297/CE Directive and in A2 EPPO (European and Mediterranean Plant Protection Organization) list, may lead to drastic yield loss, and even the death of the grapevine, if efficient control measures are not applied in a timely manner. Using healthy propagating materials, applying chemical treatment against to the vector, and eliminating infected plants are methods to control the spread of the disease, but there is no strong evidence that these methods are fully effective, since FD has been slowly spreading in EU. The dissemination of the disease is made through the leafhopper vector, Scaphoideus titanus Ball (ST), and by infected propagative material.

Current management strategies to control the disease caused by phytoplasmas like Flavescence dorée on grapevine are mainly based on uprooting of symptomatic infected plants, using of insecticides to reduce the number of insect vectors, and applying ‘Hot treatment’ to vegetative propagation material like rootstocks (silent carriers of phytoplasmas).

Diagnostics methods like PCR (Polymerase chain reaction) for early pathogen detection in plants and vectors have been developed. However, there is a need for further technological advances aiming to develop of screening methods more sensitive and specific, reliable, cost-effective and at the same time not aggressive to the environment and to public health.

MATERIAL AND METHODS
PARRA project** has been exploring the concept of equipping UAVs (Unmanned Aerial Vehicle) commonly known as a drone, with hyperspectral sensors in order to collect FD disease data samples and develop an early detection algorithm of FD symptoms (“spectral signature” of the disease).
The proposed solution explores different technologies to collect data such as different types of sensors as EO (Electro-optical), IR (Infrared) and hyperspectral installed onboard the UAVs(3)(4).
Different degrees of symptoms from two portuguese cultivares, Vinhão (red) and Loureiro (white), were compared in order to develop the FD algorithm and establish a pattern according to the environment light condition of data collected from the UAV.


.
RESULTS AND DISCUSSION
The collected data to identify the infected plants with FD are currently under analysis. The results obtained so far will be presented on this communication.
These environmental friendly tools will contribute to the development of new sustainable and eco-friendly Integrated Pest Management strategies adapted to the new paradigm of Crop Protection (very fast climate change, reduced number of pesticides in the European market, urgent need to protect the environment and an increasing circulation of plant materials around the world that is linked to the introduction of new pests and diseases in Europe).




*Consortium - Leader: TEKEVER; Partners: INIAV (Instituto Nacional de Investigação Agrária), IPVC (Instituto Politécnico de Viana do Castelo), UTAD (Universidade de Trás-os-Montes e Alto Douro), AGRICIÊNCIA

**Instituto da vinha e do Vinho


ACKNOWLEDGEMENTS

This project is co-funded by the European Commission in the scope of program Portugal 2020 under grant agreements 3447 (PARRA), for Cooperative Research and Development.


REFERENCES

(1)E. Sousa, F. Cardoso, P. Bianco, M. Guimarães and V. Pereira. 2003. “Detection and identification of phytoplasmas belonging to 16SrV-D in Scaphoideus titanus,” in Proceedings 14th Meeting ICVG, Bari, Italy..
(2)E. Sousa, P. Casati, F. Cardoso, C. Baltazar, G. Durante, F. Quaglino and P. Bianco. 2010. “Flavescence dorée phytoplasma affecting grapevine (Vitis vinifera) newly reported in Portugal” .Plant Pathology..
(3)C. Snow. 2017. “The Truth about Drones in Precision Agriculture,”Available: http://www.angeleyesuav.com/. [Accessed 08 02 2017]
(4)Jingwei Hou,, Longtang Li, Jie He .2016. Detection of grapevine leafroll disease based on 11-index imagery and ant colony clustering algorithm. Precision Agric. 17:488–505.

Agrobacterium tumefaciens is a pathogen that causes crown gall of grape and is one of the most damaging diseases of grapevine. This pathogen can cause grapevine plants death, reason why should apply some agrotechnical measures to stop their spreading in vineyards. In this context, the present work aimed to stop the proliferation of pathogenic bacteria by the application of two recipes that had in composition the following substances: garlic tincture, sodium hypochlorite, alcohol, copper sulphate. The solutions obtained were applied on galls and on several inches of stem located near them, taking into account the evolution of precipitation and irrigation. The study was conducted over two years: the first year of treatment and observations were carried out in the field and in the second year in a protected space (greenhouse). Both recipes had significant efficiency in the destruction of the pathogenand diminishing its multiplier potential, by reducing the number and size of galls as compared to the control.