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Biological control of coffee rust by antagonistic bacteria under ﬁeld conditions in Brazil
Fernando Haddad, Luiz A. Mafﬁa *, Eduardo S.G. Mizubuti, Hudson Teixeira
Departamento de Fitopatologia, Universidade Federal de Viçosa, Av. P. H.Rolfs s/n, 36570-000 Viçosa, MG, Brazil
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Rust (Hemileia vastatrix) is the most important coffee disease in Brazil. Organic coffee production has increased in the country and a research program aimed to develop alternatives to chemicals for disease control was required. Seven bacterial isolates, isolated from organic coffee plantings and selected ingreenhouse tests, were evaluated under commercial organic crop conditions in 2005 (Experiment 1) and 2005/2006 (Experiment 2), in Machado, MG, Brazil. Ten treatments consisting of the seven bacterial isolates, copper hydroxide, calcium silicate and water were applied as three or four monthly sprays in Experiment 1 or 2, respectively. Rust severity and incidence were evaluated monthly. In Experiment 1,the sprays started in January when rust incidence was 23.8%, and none of the treatments reduced rust progress signiﬁcantly. In Experiment 2, the sprays began in November 2005, when rust incidence was approximately 7.5%. There were signiﬁcant differences (P < 0.0001) between treatments regarding maximum incidence and severity (as assessed in June, 2006), the rate of increase of the incidence betweenNovember 2005 and June 2006 and for the areas under disease progress curves for both rust incidence and severity. Lower values for these treatments were obtained in the plots treated with copper hydroxide or Bacillus sp. isolate B157, and intermediate values with the Pseudomonas sp. isolate P286. In a third experiment conducted in 2007 in Ervália, MG, isolates B157 and P286 were also evaluated;isolate B157 reduced rust intensity as effectively as copper hydroxide. Isolate B157 is considered a potential biocontrol agent for coffee rust for organic crop systems in Brazil. Ó 2009 Elsevier Inc. All rights reserved.
Article history: Received 13 March 2008 Accepted 4 February 2009 Available online 13 February 2009 Keywords: Coffea arabica Hemileia vastatrix Pseudomonas Bacillus BiocontrolDisease management
1. Introduction Brazil is the largest coffee (Coffea arabica L.) producer and exporter worldwide (MAPA, 2007). There is an increasing demand, especially from Japan and the European and North American countries, for the so-called ‘‘specialty coffees”, including organic grown coffee, which have a high added-value and can attain a price twice that of the traditional coffee(Caixeta and Pedini, 2002). The organic coffee cropping system has ofﬁcial standards which prohibit the use of pesticides; even the usage of copper-based fungicides is being restricted (Carvalho et al., 2002). Although the organic cropping systems favor human health and the environment, the intensity of plant diseases is expected to be higher in these systems because of the restrictions on pesticideusage. Leaf rust (caused by Hemileia vastatrix Berk. and Br) is the most important coffee disease and can cause yield losses up to 50% (Zambolim et al., 1997). When organic and conventional growing systems were compared regarding progress of diseases, higher levels of coffee rust intensity were recorded in the organic systems (Botelho, 2006).
* Corresponding author. Fax: +55 31 3899 1091. E-mailaddress: lamafﬁa@ufv.br (L.A. Mafﬁa). 1049-9644/$ - see front matter Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.biocontrol.2009.02.004
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