Effect of fungicide application at different times on asian rust control and soybean productivity [Glycine Max (L.) Merrill] / Efeito de fungicidas aplicados em diferentes estÃdios no controle da ferrugem asiÃtica e na produtividade da soja [Glycine max (L.) merrill]

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Currently, Brazil stands out as the second largest producer and the largest exporter of soy [Glycine Max (L) Merrill], and the productivity has had a significant increase in recent harvests, causing this culture to be of extreme importance for the economy of the country. The asian rust caused by the fungus Phakopsora pachyrhizi H. Sydow &R. Sydow is among the diseases that cause great damage to the Brazilian soybean farming. It could cause a fall in productivity from 50% to 80% with a month of infection and absence of treatment. The objective of this work was to verify the effect of the use of the fungicides chlorothalonil + thiophanate methyl (Cerconil PMÂ), chlorothalonil (Cercobin 700 PMÂ), thiophanate methyl (Daconil BRÂ), Copper Hydroxide (Blue Cupravit BRÂ), and pyraclostrobin + epoxiconazole (OperaÂ) at different application times. The pulverization was accomplished at the vegetative state V6 (before flowering), at the initial flowering stage (R1), initial stage of grain formation (R5), and also the times of combined stages V6 + R1, V6+R5 and R1+R5, in the control of the Asian rust and in the soybean productivity, also including a treatment without application of fungicides, using Conquista as a culture control. The evaluations were accomplished in three phases, at 15, 30 and 45 days after the first application. The experiment was sowed on November 15th in the agricultural year 2005/06 in the experimental area of DAG/UFLA, in Lavras, MG. The results obtained in this work permitted to conclude that the Asian rust was better controlled when the fungicide Opera was used at stages R1, V6+R1 e R1+R5, followed by DaconilÂ, for the R1, V6+R1 e R1+R5 application times. The number of legumes produced by plant was altered significantly in function of the tested treatments. The application times and the tested fungicides provided significant alterations in grain productivity. The application of Opera at the various times and Cerconil at R1+R5 was responsible for the largest yields. The largest productivity was obtained with the use of the Opera fungicide. The better application times were R1 (flowering onset) and R5 (onset of grain formation). The two application system did not show to be advantageous.

ASSUNTO(S)

estÃdios de aplicaÃÃo soybean rustâs controle quÃmico ferrugem da soja application times chemical control agronomia

ACESSO AO ARTIGO

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