Abstract

PANOZZO, M; ALMIRON, N; BELLO, F  and  VAZQUEZ, D. Caracterización de aislamientos de moho verde (Penicillium digitatum) resistentes al fungicida pirimetanil en la región citrícola del río Uruguay. RIA. Rev. investig. agropecu. [online]. 2018, vol.44, n.2, pp.61-64. ISSN 1669-2314.

The continuous use of the fungicides thiabendazol and imazalil in the citrus packing houses of the Uruguay River region has led to the selection and proliferation of resistant green mold isolates, being this fungus the main cause of postharvest rot. Recently, the fungicide pyrimethanil (anilino-pyrimidine) (PYR) has been incorporated into the control programs of this disease. The objective of the present work was to study the resistance to this fungicide of a collection of isolates, obtained after this active principle was incorporated into control programs in the citrus packaging houses during a period of approximately 5 years. 122 green mold isolates were collected from Monte Caseros (Corrientes) to Concordia (Entre Ríos) during 2015. They were obtained from fruits with symptoms of the pathogen in the field and packaging. The concentration of PYR which reduces colony growth by 50% (EC50) was determined for each isolation. The mean EC50 of the field-collected isolates was 0.16 ± 0.02 μg mL^-1. No resistant isolates were observed in the field where the fungicide is not used. In contrast, 64.4% of those collected from packing houses were resistant to PYR, with an average EC50 5.51 ± 0.37 μg mL^-1. Those sensible isolates showed an EC50 mean 0.20 ± 0.02 μg mL^-1. The information provided in this work is important for monitoring susceptibility of green mold to the fungicide PYR in the citrus region of the Uruguay River. The incorporation of this fungicide in green mold control programs must be done carefully, and different strategies must be implemented to achieve effective results.

Keywords : Synthesis fungicide; Citrus postharvest rot; Resistance.

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