Impact of anthracnose on the yield of soybean subjected to chemical control in the north region of Brazil

Moab Diany Dias,Valdeci Fernandes Pinheiro,Adalberto Corrêa Café-Filho

doi:10.1590/0100-5405/2114

Moab Diany Dias, Valdeci Fernandes Pinheiro + Show 1 more

Open Access

https://doi.org/10.1590/0100-5405/2114

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Abstract

ABSTRACT Losses due to soybean anthracnose, caused by Colletotrichum truncatum, have not been systematically quantified in the field, and the efficacy of chemical control of this disease is not known. This study shows an estimate of losses associated with the disease in soybean crops in the north of the country. Two trials with cv. M9144 RR were carried out in commercial fields in Tocantins State in the 2010/2011 and 2011/2012 growing seasons, in randomized blocks, with four replicates. Foliar applications were performed on plants at R1/R2 and R5.2 stages, employing CO2-pressurized equipment and application volume of 200 L ha-1. Nine fungicides and one untreated control were compared, and the disease gradients in the two seasons were obtained. The percentage of infected pods was calculated at the R6 stage. Grain yield ranged from 3,288 to 3,708 kg/ha in the untreated plots in 2010/2011 and 2011/2012, respectively, and from 3,282 to 4,110 kg/ha in the treated plots. In the 2010/2011 season, only azoxystrobin + cyproconazole significantly reduced the disease incidence, compared to untreated control plots, not differing from the remaining treatments. In the 2011/2012 season, there were no significant differences between treated and untreated plots. Highly significant correlations (p < 0.01) were found between yield and soybean anthracnose incidence on pods in both years (r = -0.85). For each 1% increment in the disease incidence, c. 90 kg/ha of soybean grain were lost. The current study determined that significant losses due to anthracnose occur in commercial crops in the north of the country and highlighted the limitation of chemical control as anthracnose management method.

Highlights

Danos devidos à antracnose da soja, causada por Colletotrichum truncatum não foram quantificados sistematicamente no campo e a eficiência do controle químico desta doença não é conhecida
Anthracnose takes its main source of inoculum from infected seeds and crop residue, so it is one of the first diseases to establish in the crop, with lesions appearing on the cotyledons
Given the scarcity of quantitative information on damage associated with anthracnose, this study aimed to estimate the magnitude of yield losses under commercial crop conditions

Summary

Introduction

Danos devidos à antracnose da soja, causada por Colletotrichum truncatum não foram quantificados sistematicamente no campo e a eficiência do controle químico desta doença não é conhecida. Foram encontradas correlações altamente significativas (p < 0,01) entre a produtividade e a incidência da antracnose de soja nas vagens nos dois anos (r = -0.85). Other leader world producers include the United States of America, Argentina, China, and India (http://faostat.fao.org). In some places, such as Australia, soybean has been promoted as a rotation crop for its contribution to soil N content, valuable cash return, and reduction in lesion nematode populations [14, 15]. Estimates of damage to crop yield in the state of Tocantins, located in the northern region, have not yet been undertaken, a high prevalence of anthracnose has been reported [5, 6]

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