**2.1 Fungal isolation**

Nineteen samples with visible symptoms of leaf blight obtained from soybean lots not less than 0.5 ha in size, were processed. Soybean samples were collected from several places like Emilia, Margarita, Esperanza, Gobernador Crespo and San Justo, in Santa Fe Province. Sampling was carried out between January and May (2005-2006 campaign) under similar climatic conditions (Table 1).


Table 1. Climatic conditions corresponding to different meteorological stations in Santa Fe Province, Argentina. 2005-2006 Campaign. 1: Esperanza; 2: Emilia, Gobernador Crespo and San Justo; 3: Margarita; Tmax: maximum temperature; Tmin: minimum temperature; Tmed: medium temperature; RH: relative humidity.

Fig. 1. Tissue pieces being disinfected by immersion.

Fig. 2. Tissue pieces in moist chambers.

The aim of the present work was to determine the occurrence of phenotypic and genotypic

Nineteen samples with visible symptoms of leaf blight obtained from soybean lots not less than 0.5 ha in size, were processed. Soybean samples were collected from several places like Emilia, Margarita, Esperanza, Gobernador Crespo and San Justo, in Santa Fe Province. Sampling was carried out between January and May (2005-2006 campaign) under similar

**Tmax ºC Tmin ºC Tmed ºC RH %** 

**1** 26.8 14.4 22.8 67 **2** 28.8 15.0 22.5 73 **3** 28.1 15.0 22.9 70

Table 1. Climatic conditions corresponding to different meteorological stations in Santa Fe Province, Argentina. 2005-2006 Campaign. 1: Esperanza; 2: Emilia, Gobernador Crespo and San Justo; 3: Margarita; Tmax: maximum temperature; Tmin: minimum temperature; Tmed:

variability between isolates of *C. kikuchii* in various regions of Santa Fe Province.

**Meteorological Station Average** 

**2. Methods** 

**2.1 Fungal isolation** 

climatic conditions (Table 1).

medium temperature; RH: relative humidity.

Fig. 1. Tissue pieces being disinfected by immersion.

Fig. 2. Tissue pieces in moist chambers.

Tissue pieces were disinfected by immersion in 3% w/v sodium hypochlorite for 3 min, rinsed with sterile distilled water (Fig.1) and incubated in moist chambers at 26 ± 0.5 ºC, under alternate light cycles (16 h cold light and 8 h in the dark) (Salvador & Garrido, 1990). (Fig. 2).

Observation with stereoscopic magnifying lens (BOECO Germany, BTB 3-C) was performed from the 3rd day of incubation onwards. Once the conidial structure growth was verified, conidia were taken with a sterile needle and suspended in 1 mL sterile water so as to obtain a homogeneous suspension. To produce monosporic cultures, an aliquot (100 L) was spread over Potato Dextrose Agar (PDA) in a Petri dish and incubated as described above (Dunkle & Levy, 2000). Isolates were labeled with letter C and correlative numbers (Table 2), stored and subsequently included in the strain collection.


Table 2. Origin and designation of *Cercospora kikuchii* regional isolates. G. Crespo: Gobernador Crespo.
