FUNGICIDE SPRAYING TECHNOLOGIES IN THE CONTROL OF ASIAN RUST IN SOYBEAN CULTIVARS

ABSTRACT The adequacy of spraying technology in the control of Asian rust to factors related to soybean cultivars and fungicide type is fundamental for the efficiency in the control of this disease. In this context, the objective was to evaluate the chemical control of Asian soybean rust and the deposition of the fungicide applied in the crop, according to different volumes and spray nozzles. Four field experiments were set up during the 2014/2015 season, each carried out with one soybean cultivar, using: NA 5909 RR®, NS 7237 IPRO®, BMX Potência RR® and W 712 RR®. The experimental design was randomized blocks in a 2x2x2 factorial arrangement, with four replications. The first factor corresponded to the use of fungicides: [pyraclostrobin + epoxiconazole] and [pyraclostrobin + epoxiconazole] + mancozeb; the second factor, types of spray nozzle: double and triple fan; and the last factor, application volume: 60 and 120 L ha-1. The highest application volume resulted in greater deposition of droplets in the canopy of the plants, regardless of the fungicide, type of spray nozzle and cultivar. The association of fungicides [pyraclostrobin + epoxiconazole] + mancozeb showed greater efficacy in controlling rust, regardless of the type of spray nozzle and the volume applied when compared to [pyraclostrobin + epoxiconazole]. The highest volume of application promoted less disease evolution in the cultivars NA 5909 RR®, NS 7237 IPRO® and BMX Potência RR®. The yields of the cultivar were higher when the combination [pyraclostrobin + epoxiconazole] + mancozeb was used. RESUMO A adequação de tecnologia de pulverização no controle da ferrugem asiática aos fatores relacionados às cultivares de soja e tipo de fungicida é fundamental para a eficiência no controle dessa doença. Neste sentido, o objetivo foi avaliar a eficácia do controle químico da ferrugem asiática da soja e a deposição do fungicida aplicado na cultura, em função de diferentes volumes de calda e pontas de pulverização. Foram instalados quatro experimentos a campo durante a safra 2014/2015, cada um realizado com uma cultivar de soja, utilizando: NA 5909 RR®, NS 7237 IPRO®, BMX Potência RR® e W 712 RR®. O delineamento experimental foi em blocos casualizados em arranjo fatorial 2x2x2, com quatro repetições. O primeiro fator correspondeu a utilização dos fungicidas: [pyraclostrobin + epoxiconazole] e [pyraclostrobin + epoxiconazole] + mancozeb; o segundo fator, tipos de ponta de pulverização: leque duplo e trip