scholarly journals Climate change and the occurrence of downy mildew in Brazilian grapevines

2017 ◽  
Vol 52 (6) ◽  
pp. 426-434 ◽  
Author(s):  
Francislene Angelotti ◽  
Emília Hamada ◽  
Edineide Elisa Magalhães ◽  
Raquel Ghini ◽  
Lucas da Ressureição Garrido ◽  
...  

Abstract: The objective of this work was to evaluate the potential impact of climate change on the occurrence of grapevine downy mildew in Brazil. Seedlings containing four to six leaves were sprayed with a sporangia suspension containing 105 sporangia per milliliter. After spraying, the seedlings were subjected to temperatures of 26, 28, 29.1, 30.4, and 31.8°C for 24 hours. The percentage of diseased leaf area and the latent period were evaluated. Maps of the geographic and temporal distribution of the disease were made considering the monthly average of the mean air temperature and leaf wetness duration for the reference climate or climate normal (1961-1990) and the future climates (2011-2040, 2041-2070, and 2071-2100), considering the A2 and B1 gas emission scenarios, designed by the Intergovernamental Panel on Climate Change (IPCC). Favorability ranges were set and used in logic functions of the geografical information system (GIS) to generate monthly maps for grapevine downy mildew. Rising temperatures interfered with the grapevine downy mildew infections, reduced the disease severity, and increased the latent period. Future climate scenarios indicate a reduction of favorability of downy mildew in Brazil, with variability in the different grape producing regions.

2020 ◽  
Vol 158 (3) ◽  
pp. 599-614
Author(s):  
Federica Bove ◽  
Serge Savary ◽  
Laetitia Willocquet ◽  
Vittorio Rossi

Abstract The parameterisation process of a previously developed modelling structure of the grapevine-downy mildew pathosystem is described. The model incorporates primary and secondary infections, host crop growth and development, along with a linkage between disease on foliage and disease on clusters. This process-based model was developed with a main objective of understanding the behaviour of the pathosystem under different, variable, environmental conditions, or under climate change. Six scenarios of disease conduciveness were developed in order to capture the range of environmental conditions under which potential downy mildew of grapevine epidemics can develop. These climate scenarios were based on moisture and temperature factors. The scenarios were translated into vectors of parameters for primary and secondary infections in the model. Model testing was performed in three steps: (i) an analysis of potential epidemics was conducted from the literature on grapevine downy mildew in order to delineate the behaviour of the pathosystem under different scenarios; (ii) a simulation experiment was conducted to investigate the response of the model to different patterns of environmental conditions, corresponding to six scenarios of disease conduciveness; and (iii) expected and simulated epidemics under these scenarios were compared. In scenarios, the model mobilised existing quantitative information on downy mildew of grapevine and generated outputs that are congruent with expected patterns of potential epidemic. This study indicates that the model is a reliable tool for simulating accurate and robust potential epidemics of downy mildew of grapevine in a scenario analysis. This can have many applications, such as the understanding of the behaviour of the pathosystem under climate change or when partial host resistance is involved.


1996 ◽  
Vol 128 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Martha McClure ◽  
Dan T. Quiring ◽  
Jean J. Turgeon

AbstractA 2-year field study was carried out to locate and identify eggs, determine the temporal distributions of eggs and larvae, and assess the impact of Strobilomyia laricis and S. viaria on Larix laricina. Eggs of S. laricis were beige with a patterned surface and usually laid one per cone in the bud scales at the base of the cone. Eggs of S. viaria were white and smooth and usually laid one per cone between the ovuliferous scales of the cone. Strobilomyia laricis oviposited from mid- to late May and S. viaria from late May to mid-June, each species initiating oviposition at a different stage of cone phenology. Peak egg densities of S. laricis were 25 and 65% higher than those of S. viaria in 1990 and 1991, respectively. Larvae of both species completed development at the same time, from mid-June to early July. The mean number of scales eaten per cone did not differ between species; one larva damaged a mean of 8.4 scales per cone in 1990 and 10.7 scales per cone in 1991. As the number of scales per cone increased, the mean number of scales eaten increased and the mean percentage of scales eaten decreased. Cone crops were light in both years. In 1990, the only year we were able to differentiate cone maggot larvae, 44% of cones were damaged by S. laricis and only 16% by S. viaria. Together, S. laricis and S. viaria damaged 60 and 67% of the cones and destroyed 38 and 50% of the potential seed crop in 1990 and 1991, respectively.


Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2592-2598
Author(s):  
Anthony P. Keinath

The objective of this study was to evaluate fungicide applications, host resistance, and trellising, alone and in combination, as management practices for downy mildew on slicing cucumber. A split-split plot experimental design was used with three and four replications in spring and fall 2017, respectively. The whole-plot treatment was fungicide, four applications of chlorothalonil (Bravo Weather Stik 6SC) alternated with three applications of cyazofamid (Ranman 400SC), or water. Split plots were nontrellised or trellised with four strings supported by stakes. Split-split plots were cultivar Bristol, which is intermediately resistant to downy mildew, or cultivar Speedway, which is susceptible to downy mildew with similar parentage as Bristol. In both seasons, area under the disease progress curve (AUDPC) values were lower with fungicides than water for both cultivars. In the spring, AUDPC for Bristol was lower than for Speedway regardless of fungicide treatment. In the fall, Bristol had a lower AUDPC than Speedway with fungicides, but the AUDPC did not differ between the two cultivars with water. The mean AUDPC for trellised plants (376.2) was lower than for nontrellised plants (434.0; P = 0.007). Fungicide applications increased marketable and total fruit weights in both seasons (P ≤ 0.0002). Marketable weight with fungicides was almost double (93% greater) the marketable weight with water. Marketable weight was 55% greater for Bristol than for Speedway in spring, but yields did not differ between cultivars in fall (season-by-cultivar interaction, P ≤ 0.0003). Because trellising had no effect on marketable yields (P = 0.11), trellising is not recommended for managing downy mildew on slicing cucumber. Of the three management techniques examined, fungicides had the largest effects on disease and yields, followed by cultivar resistance.


2019 ◽  
Vol 11 (3) ◽  
pp. 954-969 ◽  
Author(s):  
Yann Dussert ◽  
Isabelle D Mazet ◽  
Carole Couture ◽  
Jérôme Gouzy ◽  
Marie-Christine Piron ◽  
...  

Abstract Downy mildews are obligate biotrophic oomycete pathogens that cause devastating plant diseases on economically important crops. Plasmopara viticola is the causal agent of grapevine downy mildew, a major disease in vineyards worldwide. We sequenced the genome of Pl. viticola with PacBio long reads and obtained a new 92.94 Mb assembly with high contiguity (359 scaffolds for a N50 of 706.5 kb) due to a better resolution of repeat regions. This assembly presented a high level of gene completeness, recovering 1,592 genes encoding secreted proteins involved in plant–pathogen interactions. Plasmopara viticola had a two-speed genome architecture, with secreted protein-encoding genes preferentially located in gene-sparse, repeat-rich regions and evolving rapidly, as indicated by pairwise dN/dS values. We also used short reads to assemble the genome of Plasmopara muralis, a closely related species infecting grape ivy (Parthenocissus tricuspidata). The lineage-specific proteins identified by comparative genomics analysis included a large proportion of RxLR cytoplasmic effectors and, more generally, genes with high dN/dS values. We identified 270 candidate genes under positive selection, including several genes encoding transporters and components of the RNA machinery potentially involved in host specialization. Finally, the Pl. viticola genome assembly generated here will allow the development of robust population genomics approaches for investigating the mechanisms involved in adaptation to biotic and abiotic selective pressures in this species.


Heliyon ◽  
2021 ◽  
pp. e07401
Author(s):  
Sajib Mandal ◽  
Md. Sirajul Islam ◽  
Md. Haider Ali Biswas ◽  
Sonia Akter

Author(s):  
Dede Long ◽  
Grant H. West ◽  
Rodolfo M. Nayga

Abstract The agriculture and food sectors contribute significantly to greenhouse gas emissions. About 15 percent of food-related carbon emissions are channeled through restaurants. Using a contingent valuation (CV) method with double-bounded dichotomous choice (DBDC) questions, this article investigates U.S. consumers’ willingness to pay (WTP) for an optional restaurant surcharge in support of carbon emission reduction programs. The mean estimated WTP for a surcharge is 6.05 percent of an average restaurant check, while the median WTP is 3.64 percent. Our results show that individuals have a higher WTP when the surcharge is automatically added to restaurant checks. We also find that an information nudge—a short climate change script—significantly increases WTP. Additionally, our results demonstrate that there is heterogeneity in treatment effects across consumers’ age, environmental awareness, and economic views. Our findings suggest that a surcharge program could transfer a meaningful amount of the agricultural carbon reduction burden to consumers that farmers currently shoulder.


2013 ◽  
Vol 1 (2) ◽  
pp. 239-259 ◽  
Author(s):  
Wolfgang Tschacher ◽  
Fabian Ramseyer ◽  
Claudia Bergomi

Time is a basic dimension in psychology, underlying behavior and experience. Timing and time perception constitute implicit processes that are often inaccessible to the individual person. Research in this field has shown that timing is involved in many areas of clinical significance. In the projects presented here, we combine timing with seemingly different fields of research, such as psychopathology, perceptual grouping, and embodied cognition. Focusing on the time scale of the subjective present, we report findings from three different clinical studies: (1) We studied perceived causality in schizophrenia patients, finding that perceptual grouping (‘binding’, ‘Gestalt formation’), which leads to visual causality perceptions, did not distinguish between patients and healthy controls. Patients however did integrate context (provided by the temporal distribution of auditory context stimuli) less into perceptions, in significant contrast to controls. This is consistent with reports of higher inaccuracy in schizophrenia patients’ temporal processing. (2) In a project on auditory Gestalt perception we investigated auditory perceptual grouping in schizophrenia patients. The mean dwell time was positively related to how much patients were prone to auditory hallucinations. Dwell times of auditory Gestalts may be regarded as operationalizations of the subjective present; findings thus suggested that patients with hallucinations had a shorter present. (3) The movement correlations of interacting individuals were used to study the non-verbal synchrony between therapist and patient in psychotherapy sessions. We operationalized the duration of an embodied ‘social present’ by the statistical significance of such associations, finding a window of roughly 5.7 seconds in conversing dyads. We discuss that temporal scales of nowness may be modifiable, e.g., by mindfulness. This yields promising goals for future research on timing in the clinical context: psychotherapeutic techniques may alter binding processes, hence the subjective present of individuals, and may affect the social present in therapeutic interactions.


2021 ◽  
Vol 23 (2-3) ◽  
pp. 115-132
Author(s):  
Łukasz Kułaga

Abstract The increase in sea levels, as a result of climate change in territorial aspect will have a potential impact on two major issues – maritime zones and land territory. The latter goes into the heart of the theory of the state in international law as it requires us to confront the problem of complete and permanent disappearance of a State territory. When studying these processes, one should take into account the fundamental lack of appropriate precedents and analogies in international law, especially in the context of the extinction of the state, which could be used for guidance in this respect. The article analyses sea level rise impact on baselines and agreed maritime boundaries (in particular taking into account fundamental change of circumstances rule). Furthermore, the issue of submergence of the entire territory of a State is discussed taking into account the presumption of statehood, past examples of extinction of states and the importance of recognition in this respect.


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