ABSTRACT
ISOLATION OF Venturia inaequalis, (CKE.) WINT. STRAINS TOLERANT TO SYSTEMIC FUNGICIDE FROM CURICO, CHILE

Iris Carreña I.1 y Adriana Pinto de Torres1
 

Isolates of Venturia inaequalis (Cke.) Wint. froro an apple orchard (Curicó, Chile) in which B.enlate and Cercobin had given poor scab control were determined tolerant in culture to these fungicides. New lesions, free of contamination and germinatedspores were chosen and also monosporic cultures were utilized.
Spores of V. inaequalis from new Iesions on fruits w,ere incubated at 20-22°C in PDA medium with 5 ppm BenomyI for 24 hrs; germinated spores were transfered toanothers PDA medium containing 5 ppm Benomyl.
These isolates were tranfered to PDA medium containing 0 - 5 - 100 - 250 and 500 ppm Benomyl and MethyI tiophanate. The isoIates from sprayed orchards deveIoped and sporuIated in 250 ppm BenomyI and 5 ppm MethyI tiophanate forming typicaI coIonies, demonstrating 10 foId toIerance over susceptible strains isoIated from fruits obtained from never sprayed trees.

Keywords:
1Ings. Agrs. Fitopatólogos, Programa Frutales y Viñas. Estación Experimental La Platina, Instituto de Investigaciones Agropecuarias (INIA), Casilla 5427, Santiago, Chile.