Antagonistic effect of Trichoderma spp. on Septoria tritici, causal agent of leaf spot of wheat under field conditions

PERELLÓ, A.; MORENO, V.; MÓNACO, C.; SIMÓN, MR; CORDO, C.

BIOCONTROL (DORDRECHT)

Springer

Lugar: Netherlands; Año: 2006

1386-6141

Biological control of Septoria tritici blotch on wheat by Trichoderma spp. under field conditions in Argentina. Analía PERELLÓ 1,3*,  María Virginia MORENO 1,3, Cecilia MÓNACO 1,2, María Rosa SIMÓN 4 and Cristina CORDO 1,2 1 Centro de Investigaciones de Fitopatología (CIDEFI). Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata. 60 y 119, 1900 La Plata, Provincia de Buenos Aires, Argentina. 2 Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC), 3 Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 4Cerealicultura. *Author for correspondence: Fax.: +54-221-425-2346. e-mail:anaperello@yahoo.com.ar fitopato@ceres.agro.unlp.edu.ar Abstract. Biological control is an additional tool available for the design of more sustainable control strategies of wheat diseases. Trichoderma spp. have previously been used as biocontrol agents to protect wheat plant against  leaf spots diseases in Argentina, but the information from field assays is scarce. The effectiveness of four Trichoderma harzianum Rifai strains and one T. koningii Oudem. strain reducing the incidence and severity of leaf blotch of wheat caused by Septoria tritici (STB) under two formulation conditions: spore suspension and coated-seed technique was studied under field conditions. Significant differences between wheat cultivars, formulation types and growth stages were found. In 2003, at tillering stage, all the treatments tested (except SST1 for incidence) effectively reduced the incidence or the severity of the disease compared to the control. Similarly, in 2004, ten of the treatments reduced the severity at tillering. At heading stage, none of the treatments tested caused a significant decrease of the disease. These results, indicated, therefore that the antagonism was effective at an early stage of the disease only. Some isolates, as CST4 and CST2, reduced the incidence value of STB to 40 % and the severity value to 70%  of the control values applied as coated-seed formulation  On the other hand, isolates T4 and T2 showed the greatest effectiveness for controlling STB, with similar reduction values to that showed by the fungicide (Folicur®) application treatment. The results of this study indicated that although the immediate impact of Trichoderma isolates may be seen as reduced incidence and severity on the first stages of STB, in the long term, the same disease levels as found in untreated sites may be attained. This study also demonstrated that the incorporation of Trichoderma as a biocontrol preparation may be a promising step towards reducing STB disease in the field and levels of fungicide residues in the context of a more integrated approach to the problem. Key words: wheat diseases, biological control.