Data/hora: 08/06/2024 17:48:48

Biblioteca(s): | Epagri-Sede.
Data corrente: | 25/01/2017
Data da última atualização: | 25/01/2017
Autoria: | ARAÚJO, E. R.; ALVES, D. P.; KNOTH, J. R.
Título: | Weather-based decision support reduces the fungicide spraying to control onion downy mildew.
Ano de publicação: | 2017
Fonte/Imprenta: | Crop Protection, Amsterdam, v. 92, p. 89-92, 2017.
Idioma: | Inglês

Conteúdo:

Onion downy mildew is a major production constraint. Weather-based decision support has been an
important tool for the rational use of fungicides. The present study established a chemical management
strategy of the disease based on temperature and relative humidity. We defined daily severity values
(DSV) according to temperature range (08e13.9 C; 14e21.9 C; 22e29 C) and relative humidity 90% to
carry out the spraying. The treatments mancozeb/copper oxychloride or metalaxyl-M/chlorothalonil
were applied when the summations of the DSV reached the 6e11 range, or 12e17 range, or 18, besides
weekly sprays using these fungicides or water. The area under disease progress curve (AUDPC) and
yield of commercial bulbs were calculated. In both years evaluated (2014, 2015), we managed to reduce
the number of metalaxyl-M/chlorothalonil sprays without compromising commercial yield. In 2014, the
yield values for all treatments using metalaxyl-M/chlorothalonil were significantly higher than those
which used mancozeb/copper oxychloride and control. In fact, with one spray less the routine weekly
application, yield was 48.203 tons per hectare, while following the routine weekly application it was
42.411 tons per hectare. In 2015, we have reduced the number of metalaxyl-M/chlorothalonil sprays by
20%, while maintaining the same levels of AUDPC and yield. For both years, treatments with mancozeb/
copper oxychloride did not differ from the control (water weekly). The rational use of fungicides is a key
element for establishing an integrated production system of onion.

Palavras-Chave: | Allium cepa; Peronospora destructor; Rational management.
Categoria do assunto: | X Pesquisa, Tecnologia e Engenharia
URL: | http://intranetdoc.epagri.sc.gov.br/producao_tecnico_cientifica/DOC_38833.pdf
Registro original: | Epagri-Sede (Epagri-Sede)
Exemplares: | Epagri-Sede - (100960-1) - UPC - AP - DD -  -  -  - DIS