Dose e taxa de aplicação de fungicida no controle da ferrugem da folha (Puccinia triticina) e da mancha amarela (Pyrenophora tritici repentis) do trigo

Abstract

The aim of this paper was to study the role of dose and rate of application, and the effect of concentration of fungicide in the spray solution resulted from the interaction of these factors, in the control of leaf rust and yellow spot of wheat. It was conducted two experiments, the first used the CD 104 cultivar (susceptible to leaf rust and yellow spot). The experimental design was an factorial 3 x 3 + untreated 143, 286 and 429 L.ha -1 ). The second experiment used the BRS 208 cultivar (resistant to leaf rust and moderately resistant to yellow spot). The experimental design was an factorial 2 x 2 + untreated control, consisting the factors dose (0,2 and 0,3 L.ha -1 ) and application rate (143 and 286 L.ha -1 ). The applications were made with a coastal sprayer by CO 2 , pressure of 250 kPa, XR 110-02 nozzle, which generated an application rate of 143 L.ha -1 . The respective rates of each treatment were changed by the number of sprayers per area. It was also used a spore trap denominated Siga, associated with meteorological data and weather forecast, which detected spores of rust and yellow spot before the symptoms in the plants, helping in the identification of disease and in the timing of application. There wasn´t any interaction between dose and rate of application for any of the experiments, therefore, there wasn´t effect of concentration of fungicide in control. The dose and rate of application just influenced in the control of the yellow spot. Higher doses and rates were more effective. However, no difference was observed for yield and hectolitre weight among treatments, except untreated control.control, that involve the factors dose (0,25, 0,30 and 0,35 L.ha -1 ) and application rate (

Adjuvants in Fungicide Spraying in Wheat and Soybean Crops

“…The reduction potential of crop yield capacity by the occurrence of diseases is therefore confirmed, as described by OLIVEIRA et al (2015) and WEIRICH NETO (2013) on the conclusions of their work.…”

“…Diseases are among the factors that restrict yield (OLIVEIRA et al, 2015;WEIRICH NETO, 2013). Their incidence and severity vary each season depending on the cultivar, crop rotation, weather conditions and source of pathogens inoculum.…”

Spray volumes for agrochemicals applied to soybean and wheat crops

“…In the wheat crop, Cooke et al (1989) did not find significant differences in the redistribution of leaf surface deposits of pesticides and disease control caused by Pseudocercosporella herpotrichoides with spray volumes from 15 to 200 L ha -1 . When controlling wheat diseases by applying fungicides to the plants, Oliveira et al (2015) sprayed syrup volumes from 143 to 429 L ha -1 , not verifying differences in productivity between the treatments. However, when testing techniques for applying fungicide to control gibberella (Gibberella zeae), Panisson et al (2003) recommend a spray volume of 200 L ha -1 .…”

Aplicação De Fungicidas Visando O Controle De Mancha Amarela E Ferrugem Da Folha Em Trigo

“…é favorecida pela utilização de cultivares suscetíveis. Além disso, havendo inóculo primário presente na lavoura no início da safra, associado a condições de molhamento foliar (30 horas) e temperaturas favoráveis (18 a 28°C), tornam a infecção facilitada (OLIVEIRA et al, 2015;REIS e CASA, 2016).…”

“…Uma das formas de controle dessas doenças é o uso de fungicidas, pois permite redução de perdas de rendimento e produtividade da lavoura (OLIVEIRA et al, 2015). O uso racional dos fungicidas a campo, tem gerado efeitos positivos no controle de doenças em curto prazo.…”