ABSTRACT
In the last crop seasons, the complex of late season diseases (CLSD) of soybean (Glycine max L. (Merrill)), has been causing considerable reductions in the crop yield. Currently, there are no cultivars resistant to all pathogens that causes CLSD. The present study evaluated the effect of applying the acibenzolar-S-methyl resistance inducer, alternative products and fungicide on the severity of CLSD in the soybean cultivar BMX Potência RR during the 2013/2014 and 2014/2015 crops, in the field. The treatments for the experiments were: 1 - control (water); 2 - acibenzolar-S-methyl; 3 - calcium; 4 - micronutrients: copper, manganese and zinc; 5 - micronutrients: manganese, zinc and molybdenum; 6 - nitrogen-potassium fertilizer; 7 - Ascophyllum nodosum and 8 - azoxystrobin + cyproconazole with the addition of the adjuvant. Four applications of alternative products and two of fungicide were carried out in both harvests. A diagrammatic scale assessed the severity of CLSD at the phenological stage R7.1. The acibenzolar-S-methyl resistance inducer, alternative products (macro and micronutrients) and A. nodosum had no effect on the severity of CLSD in the two harvests. The fungicide (azoxystrobin + cyproconazole) reduced the severity of CLSD and prevented damage to productivity in both experiments.
Nas últimas safras, o complexo de doenças de final de ciclo (DFC) da soja (Glycine max L. (Merrill)), vem provocando reduções consideráveis no rendimento da cultura. Atualmente, não há variedades resistentes a todos os patógenos causadores das DFC. O objetivo do presente trabalho foi avaliar o efeito da aplicação do indutor de resistência acibenzolar-S-methyl, produtos alternativos e fungicida na severidade de DFC na cultivar de soja BMX Potência RR durante as safras 2013/2014 e 2014/2015, em campo. Os tratamentos para os experimentos foram: 1 - testemunha (água); 2 - acibenzolar-S-methyl; 3 - cálcio; 4 - micronutrientes: cobre, manganês e zinco; 5 - micronutrientes: manganês, zinco e molibdênio; 6 - adubo NK; 7 - Ascophyllum nodosum e 8 - azoxistrobina + ciproconazol com adição do adjuvante. Foram realizadas quatro aplicações dos produtos alternativos e duas do fungicida, nas duas safras. A severidade de DFC foi avaliada por escala diagramática no estádio fenológico R7.1. O indutor de resistência acibenzolar-S-methyl, os produtos alternativos (macro e micronutrientes) e A. nodosum não apresentaram efeito sobre a severidade das DFC nas duas safras. O fungicida (azoxistrobina + ciproconazol) reduziu a severidade das DFC e evitou danos a produtividade nos dois experimentos.
Subject(s)
Soybeans/microbiology , Fungicides, Industrial/administration & dosage , Cercospora , Agricultural CultivationABSTRACT
The occurrence of powdery mildew (Microsphaera diffusa) in soybean (Glycine max L.) has increased in the last harvests. In order to study the efficiency of powdery mildew control due to the application of alternative products and conventional fungicide, trials were conducted in Ponta Grossa, PR, Brazil, during the 2013/2014 and 2014/2015 growing seasons. The design used was randomized blocks with four replications. The treatments for the experiments were: 1 - control; 2 - acibenzolar-S-methyl (Bion 500 WG®); 3 - calcium (Max Fruit®); 4 - Micronutrients: copper, manganese and zinc (Wert Plus®); 5 - Micronutrients: manganese, zinc and molybdenum (V6®); 6 - NK fertilizer (Hight Roots®); 7 - Ascophyllum nodosum (Acadian®) and 8 - fungicide (azoxystrobin + cyproconazole) (Priori XTRA®) with the addition of the adjuvant. Four applications of alternative products (phenological stages V3, V6, R1 and R5.1) and two of fungicide (phenological stages R1 and R5.1) were carried out. The parameters evaluated were powdery mildew severity and productivity. The severity data made it possible to calculate the area under the disease progress curve (AUDPG). Alternative products didn't reduce powdery mildew in the two harvests. The conventional fungicide treatment was the only one that controlled powdery mildew and didn't reduce the productivity in both experiments.
Subject(s)
Pesticides , Soybeans , Fungicides, Industrial , Erysiphe/pathogenicityABSTRACT
RESUMO: O míldio da soja é disseminado em todo mundo. Entretanto, o dano que ele causa não tem sido estudado no Brasil. O objetivo deste trabalho foi avaliar quais componentes de rendimento da soja são afetados por essa doença e determinar o coeficiente de dano. Dois experimentos foram conduzidos, um em Castro (2006/07) e outro em Ponta Grossa (2007/08), no Estado do Paraná, Brasil. O delineamento experimental foi de blocos ao acaso com (i) seis tratamentos e cinco repetições para os experimentos de campo, safras 2006/07, e (ii) oito tratamentos e quatro repetições para 2007/08. Foram aplicados fosfito de potássio (750g ia ha-1), propamocarb + fenamidona (900g ia ha-1) e mancozeb (2,400g ia ha-1). Em todos os tratamentos, a severidade máxima da infecção pelo míldio ocorreu no estádio R5.3 e a porcentagem de severidade variou entre 0 e 43%. O gradiente da doença foi obtido apenas na segunda safra. Equações de danos foram geradas para o peso de grãos e produtividade. O número de grãos por vagem e o número de vagens por planta não foram afetados pelo míldio mas o peso de 1000 sementes por planta foi reduzido linearmente com o aumento da severidade do míldio.
ABSTRACT: Downy mildew is widespread throughout the world. However, the damage that it causes has not been studied in Brazil yet. The objective of this work was to evaluate which components of soybean yield are affected by downy mildew and to determine the coefficient of damage. Two field experiments were conducted in Castro (2006/07) and Ponta Grossa (2007/08) in the state of Parana, Brazil. The experimental design consisted of completely randomized blocks of (i) six treatments and five replications for the 2006/07 and (ii) eight treatments and four replications for the 2007/08 field experiments. Potassium phosphite (750g a.i. ha-1), propamocarb + fenamidone (900g a.i. ha-1) and mancozeb (2400g a.i. ha-1) were applied. In all of the treatments, the maximum severity of downy mildew infection occurred at growth stage R5.3, and the percentage of severity ranged between 0 and 43%. The disease gradient was obtained only on the second season. Equations of damage were generated for the yield and grain weight. The number of grains per pod and the number of pods per plant were not affected by downy mildew but, the weight of 1000 seeds per plant was reduced linearly with increasing of mildew severity.