Data/hora: 14/05/2024 17:05:22

Biblioteca(s): | Epagri-Sede.
Data corrente: | 08/12/2023
Data da última atualização: | 08/12/2023
Autoria: | ARAÚJO, E. R.; RESENDE, R. S.
Título: | Efficacy of fungicide treatments to control onion downy mildew in Brazil, 2022.
Ano de publicação: | 2023
Fonte/Imprenta: | Plant Disease Management Reports, St. Paul, MN, v. 17, 2023.
Idioma: | Inglês

Conteúdo:

The State of Santa Catarina is the largest Brazilian producer of onions, with an annual production of over 400
thousand tons. Onion downy mildew (Peronospora destructor) is the main onion disease in the state. The management
of the disease is carried out through frequent fungicides sprays (one to two sprays per week). This trial aimed to
evaluate the effect of fungicide sprays on the area under the disease progress curve (AUDPC) and on the commercial
yield of onion in experimental field plots. Onion seedlings were grown on a soil bed and approximately 60 days after
sowing, they were transplanted (12 Jul) to the experimental area. The experimental plots consisted of 150 plants (six
rows with 25 plants) arranged in a spacing of 0.10 m (between plants) and 0.35 m (between rows), simulating a plant
density of approximately 300,000 plants per hectare. The treatments started 30 days after transplanting. Ten weekly
sprays were performed, with a volume corresponding to 500 L/ha. The severity was assessed every two weeks using a
rating description scale, which assigns scores to the entire plot (score 1 = 0% severity to score 9 = 100% severity). The
values from scale scores of the experimental plots were used to calculate AUDPC. The harvest was carried out 121
days after transplanting. Commercial yield (onion bulbs with diameter &#8805; 35 mm) was calculated from the central rows
of each plot, discarding single border rows. The experiment was randomised in blocks designed with four replications.
The data were analysed using ANOVA and, in case of significance of the treatments, means were grouped with the
Scott-Knott clustering algorithm. The disease occurred naturally, allowing for proper evaluation of the trial. Antracol® + two applications of Zorvec
Encantia® resulted in the highest yield, with an increase of 47.5% in relation to the control treatment. The treatments
Zorvec Encantia®, Ridomil Gold® MZ, and Completto® differed from the control, with an increase of 33.6%, 27.0 %
and 23.5%, respectively. No visual phytotoxicity symptoms were observed in the trial.

Thesagro: | Allium cepa; disease management; Peronospora destructor.
Categoria do assunto: | F Plantas e Produtos de Origem Vegetal
URL: | http://intranetdoc.epagri.sc.gov.br/producao_tecnico_cientifica/DOC_59505.pdf
Registro original: | Epagri-Sede (Epagri-Sede)
Exemplares: | Epagri-Sede - (108962-1) - UPC - AP - DD -  -  -  - DIS