TY - JOUR
T1 - Using hydro-thermal time for assessing rice blast risk in subtropical Brazil
AU - Silva, Michel Rocha da
AU - Streck, Nereu Augusto
AU - Yang, Haishun
AU - Ogoshi, Claudio
AU - da Costa, Ivan Francisco Dressler
AU - Rossato, Ioran Guedes
AU - Pereira, Vladison Fogliato
AU - Meus, Lorenzo Dalcin
AU - Zanon, Alencar Junior
N1 - Funding Information:
We thank IRGA extensionists Geter Machado, Luciano Alegre and Pablo Mazzuco, and all colleagues from Field Crops team at Universidade Federal de Santa Maria, Universidade Federal de Pelotas and Universidade Federal do Pampa – Campus Itaqui for their help in the field experiments. We also thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for provide a fellowship to M.R. da Silva (Project no.: 88882.427646/2019-01) and to support a 6-mo internship at the University of Nebraska-Lincoln (Project no.: 88887.351533/2019-00). Part of the data collection for this project was funded by Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS) (Project no. 17/2551-0000937-1).
Funding Information:
We thank IRGA extensionists Geter Machado, Luciano Alegre and Pablo Mazzuco, and all colleagues from Field Crops team at Universidade Federal de Santa Maria, Universidade Federal de Pelotas and Universidade Federal do Pampa – Campus Itaqui for their help in the field experiments. We also thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for provide a fellowship to M.R. da Silva (Project no.: 88882.427646/2019‐01) and to support a 6‐mo internship at the University of Nebraska‐Lincoln (Project no.: 88887.351533/2019‐00). Part of the data collection for this project was funded by Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS) (Project no. 17/2551‐0000937‐1).
Publisher Copyright:
© 2021 The Authors. Agronomy Journal © 2021 American Society of Agronomy.
PY - 2021/7/1
Y1 - 2021/7/1
N2 - In South Brazil, interannual variability leads to contrasting blast epidemics across years, varying from years when symptoms can barely be seen up to years with complete yield losses. To avoid yield losses, rice (Oryza sativa L.) farmers apply more than two fungicide applications per rice growing season, even if weather conditions are not favorable for blast development. The objective in this study was to use accumulated hourly hydro-thermal time (HTT) to assess interannual and regional weather variability for rice blast risk, using large data collected from multiple locations and years in southern Brazil. For each year × site × cultivar combination, HTT was calculated using hourly data of mean air temperature, relative humidity, and wind speed collected from weather stations. The HTT was correlated with blast onset to define a threshold for blast onset. The seasonal HTT between years × sites ranged from 5.1 to 725.3 °C h−1 year−1. Blast risk started after accumulating HTT of 33.6, 66.8, and 75.6 °C h−1 from 1 June until rice emergence (EM) and after accumulating HTT of 12.5, 55.3, and 121.8 °C h−1 after EM for susceptible, medium-resistant, and resistant rice cultivars, respectively. Our results strongly suggest that it is possible to improve fungicide management using the HTT approach over the calendar-based approach, once we were able to discriminate the cultivar and year influence, the two most important factors on rice blast epidemics in southern Brazil.
AB - In South Brazil, interannual variability leads to contrasting blast epidemics across years, varying from years when symptoms can barely be seen up to years with complete yield losses. To avoid yield losses, rice (Oryza sativa L.) farmers apply more than two fungicide applications per rice growing season, even if weather conditions are not favorable for blast development. The objective in this study was to use accumulated hourly hydro-thermal time (HTT) to assess interannual and regional weather variability for rice blast risk, using large data collected from multiple locations and years in southern Brazil. For each year × site × cultivar combination, HTT was calculated using hourly data of mean air temperature, relative humidity, and wind speed collected from weather stations. The HTT was correlated with blast onset to define a threshold for blast onset. The seasonal HTT between years × sites ranged from 5.1 to 725.3 °C h−1 year−1. Blast risk started after accumulating HTT of 33.6, 66.8, and 75.6 °C h−1 from 1 June until rice emergence (EM) and after accumulating HTT of 12.5, 55.3, and 121.8 °C h−1 after EM for susceptible, medium-resistant, and resistant rice cultivars, respectively. Our results strongly suggest that it is possible to improve fungicide management using the HTT approach over the calendar-based approach, once we were able to discriminate the cultivar and year influence, the two most important factors on rice blast epidemics in southern Brazil.
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U2 - 10.1002/agj2.20731
DO - 10.1002/agj2.20731
M3 - Article
AN - SCOPUS:85108830132
VL - 113
SP - 3548
EP - 3559
JO - Journal of Production Agriculture
JF - Journal of Production Agriculture
SN - 0002-1962
IS - 4
ER -