Abstract:In January and February 2013 occurred a SouthAmerican leaf blight epidemic in regions considered as escape zones, causing concern to rubber tree growers and throughout the rubber industry. A possible adaptation of the fungus to escape zones was raised and the consistency of disease control by the use of the binomial: plants with uniform renewal of leaves + dry season, typical of the escape zones, was questioned. The aim of this work was to bring relevant information to the rubber growers about the interaction … Show more
“…Therefore, temperature turns to a superfluous criterion. There are precedents for the temporary loss of immunity to SALB in some established Brazilian 'escape zones' due to unusually humid weather conditions [21], but cases relating to temperature anomalies have not been reported.…”
Section: Discussionmentioning
confidence: 99%
“…In the 1970s and 1980s, a series of programs encouraging natural rubber production (Programa de Incentivo à Produção de Borracha Vegetal-PROBOR) was conducted by the Brazilian government to increase national self-sufficiency, and although not successful, revealed that rubber trees could be grown in some areas of Brazil (mainly in some parts of São Paulo State) without being affected by SALB [21]. These "escape zones" are colder and experience an annual dry period that coincides with the refoliation period of the rubber trees [22].…”
South American leaf blight (SALB) of Para rubber trees (Hevea brasiliensis Muell. Arg.) is a serious fungal disease that hinders rubber production in the Americas and raises concerns over the future of rubber cultivation in Asia and Africa. The existing evidence of the influence of weather conditions on SALB outbreaks in Brazil has motivated a number of assessment studies seeking to produce risk maps that illustrate this relationship. Subjects with dynamic and cyclical spatiotemporal features need to embody sufficiently fine spatial resolution and temporal granulation for both input data and outputs in order to be able to reveal the desired patterns. Here, we apply emerging hot spot analysis to three decades of gridded daily precipitation and surface relative humidity data to depict their temporal and geographical patterns in relation to the occurrence of weather conditions that may lead to the emergence of SALB. Inferential improvements through improved handling of the uncertainties and fine-scaled temporal breakdown of the analysis have been achieved in this study. We have overlaid maps of the potential distribution of rubber plantations with the resulting dynamic and static maps of the SALB hot spot analysis to highlight regions of distinctly high and low climatic susceptibility for the emergence of SALB. Our findings highlight the extent of low-risk areas that exist within the rubber growing areas outside of the 10° equatorial belt.
“…Therefore, temperature turns to a superfluous criterion. There are precedents for the temporary loss of immunity to SALB in some established Brazilian 'escape zones' due to unusually humid weather conditions [21], but cases relating to temperature anomalies have not been reported.…”
Section: Discussionmentioning
confidence: 99%
“…In the 1970s and 1980s, a series of programs encouraging natural rubber production (Programa de Incentivo à Produção de Borracha Vegetal-PROBOR) was conducted by the Brazilian government to increase national self-sufficiency, and although not successful, revealed that rubber trees could be grown in some areas of Brazil (mainly in some parts of São Paulo State) without being affected by SALB [21]. These "escape zones" are colder and experience an annual dry period that coincides with the refoliation period of the rubber trees [22].…”
South American leaf blight (SALB) of Para rubber trees (Hevea brasiliensis Muell. Arg.) is a serious fungal disease that hinders rubber production in the Americas and raises concerns over the future of rubber cultivation in Asia and Africa. The existing evidence of the influence of weather conditions on SALB outbreaks in Brazil has motivated a number of assessment studies seeking to produce risk maps that illustrate this relationship. Subjects with dynamic and cyclical spatiotemporal features need to embody sufficiently fine spatial resolution and temporal granulation for both input data and outputs in order to be able to reveal the desired patterns. Here, we apply emerging hot spot analysis to three decades of gridded daily precipitation and surface relative humidity data to depict their temporal and geographical patterns in relation to the occurrence of weather conditions that may lead to the emergence of SALB. Inferential improvements through improved handling of the uncertainties and fine-scaled temporal breakdown of the analysis have been achieved in this study. We have overlaid maps of the potential distribution of rubber plantations with the resulting dynamic and static maps of the SALB hot spot analysis to highlight regions of distinctly high and low climatic susceptibility for the emergence of SALB. Our findings highlight the extent of low-risk areas that exist within the rubber growing areas outside of the 10° equatorial belt.
“…Climatologically, SACZ system is responsible for the considerable amount of summer rainfall among the Central-West, Southeast, and part of North and Northeast regions, causing humidity accumulation during the summer, which must have favored such leaf blight epidemics at the beginning of the year in São Paulo, Mato Grosso do Sul, Mato Grosso, and Goiás States. On the other hand, the absence of this system causes drastic reduction in rainfall in these regions, consequently leading to losses in agricultural production and risk of water and energy rationing [13].…”
Section: Epidemiology Of South American Leaf Blightmentioning
confidence: 99%
“…As SACZ phenomenon is common in Brazil, new leaf blight epidemics are expected when a highly humid period coincides with the presence of new leaves in the rubber tree, since the pathogen is common, at low intensity, even in "scape" zones. The use of productive clones resistant to leaf blight is welcome, even for "scape" zones [13].…”
Section: Epidemiology Of South American Leaf Blightmentioning
The rubber tree (Hevea spp.) is one of the main forest crops in tropical regions due commercialization of natural rubber. Brazil currently imports most rubber that is consumed. According to the International Rubber Study Group, for an annual consumption of 350,000 tons in Brazil, 135,000 tons were produced, whereas 215,000 tons were imported. This failure of rubber cultivation in Brazil is primarily due to South American leaf blight (SALB), a disease caused by the fungus Microcyclus ulei (P. Henn. v. Arx.). The fungus is present in all Brazilian rubber-producing regions and attacks young leaflets, causing abscission and, ultimately, death of the tree. This disease occurs in almost all areas of rubber tree plantations in Central and South America. Strategies used to manage SALB are based on the use of fungicides in nurseries and young plantations and the use of resistant clones; on phenological aspects, taking into account the leaf shedding patterns of adult rubber trees, which in certain environments provide defense in addition to resistance; and on climatic factors that are favorable or unfavorable to epidemic development. The aim of this chapter was to describe all aspects related to the epidemiology and management of leaf blight in Brazil.
“…Rubber trees are cultivated in the southeastern and centralwestern regions of Brazil to attend to high commercial demands for natural rubber, but also to escape from the fungal disease known as South American leaf blight caused by Microcyclus ulei (Henn.) Arx, which attacks plants in the Amazon region (6). One of the problems linked to the cultivation of H. brasiliensis (7,8) in these new areas (known as escape zones from the leaf fungus), however, is the presence of regions with warm frontand/or irregular rainfall regimes that impose water stress conditions (5).…”
Rubber tree cultivation is limited in many regions by abiotic factors such as drought. We investigated the biochemical mechanisms responsible for responses to, and recovery from, drought conditions during the establishment phase of four high latex producing rubber tree clones (RRIM600, IAC40, PR255 and GT1). Five-month-old plants were exposed to 32 days of water restriction, followed by 15 days of soil rehydration. Leaf area, as well as their osmolyte accumulations, saccharolytic enzyme activity, and oxidative stress markers, were accompanied. Although clones IAC40 and PR255 responded more precociously to drought conditions, halting leaf expansion before clones GT1 and RRIM600, they demonstrated slow recuperation after reestablishing irrigation. The greater tolerances of clones RRIM600 and GT1 to drought conditions were related to greater vacuolar invertase (VINV) activity in their leaves, which guaranteed more significant accumulations of vacuolar reducing sugars (RS). Similar to RS, glycine betaine accumulations were related to osmoprotection and to reducing oxidative damage (lipidic peroxidation) caused by water deficit conditions. The observed decreases in cytosol neutral invertase (AINV) and cell wall insoluble invertase (CWINV) activities, which resulted in cytosol hexose decreases, may be related to increases in antioxidant enzyme (superoxide dismutase and ascorbate peroxidase) activities in the leaves in response to water deficit conditions. As such, the introduction of specific sugars (RS) and the modulation of key carbon metabolism enzymes, such as VINV, are promising strategies for promoting drought tolerance in rubber tree clones.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.