Controlling Asian soybean rust (Phakopsora pachyrhizi) with Bacillus spp. and coffee oil Dalton Vinicio Dorighello a , Wagner Bettiol b, * , Nilson Borlina Maia c , Regina Maria Vilas B ^ oas de Campos Leite d a Universidade Estadual Paulista “Júlio de Mesquita Filho”, FCA/Campus Botucatu,18.610-307, Botucatu, SP, Brazil b Embrapa Environment, CP 69, CEP.13820-000, Jaguariúna, SP, Brazil c Instituto Agron^ omico de Campinas, Centro de Horticultura e Plantas Arom aticas e Medicinais, Campinas, SP, Brazil d Embrapa Soybean, CP 231, CEP 86001-970, Londrina, PR, Brazil article info Article history: Received 8 April 2014 Received in revised form 22 September 2014 Accepted 23 September 2014 Available online Keywords: Biological control Alternative control Natural products Glycine max abstract Asian soybean rust is currently the main soybean disease in Brazil and its control is primarily accom- plished with fungicides. This study evaluated the potential of Bacillus spp. and coffee oil, alone and combined with fungicide, to inhibit the germination of Phakopsora pachyrhizi uredospores and control the disease on detached leaves and plants in greenhouse and field conditions. The trials were carried out using the BRS 316 RR soybean cultivar. Bacillus subtilis (QST-713) and Bacillus pumilus (QST-2808) isolates, roasted and crude coffee oils used individually, as well as coffee oils combined with half dose of fungicide, inhibited uredospore germination by 100%. In tests with detached leaves, B. subtilis (isolates QST-713, AP-3, and AP-51) and B. pumilus (QST-2808) reduced disease severity by 98.6, 75.3, 61.2, and 97.7%, respectively. The reductions resulting from crude and roasted coffee oils were 80.1 and 87.7% compared to 77.5, and 84.4%, respectively, at concentrations of 2 and 1%. Under greenhouse conditions, all treatments, except B. subtilis AP-51, reduced the area under the disease progress curve (AUDPC), while under field conditions, the B. subtilis QST-713 isolate and roasted coffee oil at 1 and 2% reduced disease severity by 23, 18, and 23%, respectively. The results indicate that B. subtilis, B. pumilus, and coffee oils exhibit the potential to control Asian soybean rust disease. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Brazil is the second largest soybean producer worldwide. During the 2011/2012-crop season, 66.38 million tons were produced (CONAB, 2012). Asian soybean rust (Phakopsora pachyrhizi) is currently the main disease of the crop and can reduce production by 90% (Godoy et al., 2009). In the 2012/2013-crop season, US$1.186 million was spent on fungicides for use on soybean (SINDAG, 2013), primarily to control the rust. Despite the efficacy of fungicides to control the disease, the intensive use of fungicides can select pathogen-resistant populations, hindering management in consecutive crop seasons (Cook, 2001; Miles et al., 2005) and causing biological imbalances and environmental contamination. Despite the fact that the majority of the fungicides recom- mended for control of Asian soybean rust are highly effective in reducing disease severity and increasing yield, results show a clear difference in efficacy among active ingredients alone or in combi- nation, critical information that must be taken into account when choosing a fungicide for rust control (Scherm et al., 2009). Ac- cording Godoy (2012), the efficiency of the triazoles in controlling the Asian soybean rust has decrease, enhancing the necessity of new alternatives to arrange a management program for the reduction the fungicides dependency. The biocontrol of Asian soybean rust lacks thorough studies (Goellner et al., 2010). However, Ward et al. (2012) found that Simplicillium lanosoniveum reduced the number of uredia on soy- bean leaves by four times and increased the number of reddish- brown (RB) injuries, i.e., less sporulation and reduced spore germination. Reduced disease severity in the presence of S. lanosoniveum was reported by Ward et al. (2012), under field conditions. The hyperparasites Verticillium psalliotae (Saksirirat and Hoppe, 1991) and Trichothecium roseum (Sangit and Jha, 2002) have been discussed as potential biocontrol agents for Asian soybean rust. Biocontrol has shown effectiveness in controlling rust in * Corresponding author. Tel.: þ55 19 33112662. E-mail addresses: wagnerbettiol@gmail.com, wagner.bettiol@embrapa.br (W. Bettiol). Contents lists available at ScienceDirect Crop Protection journal homepage: www.elsevier.com/locate/cropro http://dx.doi.org/10.1016/j.cropro.2014.09.017 0261-2194/© 2014 Elsevier Ltd. All rights reserved. Crop Protection 67 (2015) 59e65