Introduction Strawberry (Fragaria x ananassa Duch.) is a non- climateric fruit characterized by a short postharvest life, often estimated in less than 5 days. It is very prone to rapid dehydration, physiological disorders, bruising and other mechanical injuries, and to infections caused by several pathogens that can rapidly reduce quality of ripe fruits. These factors hinder to achieve export market and have limited strawberry production in Chile. Effect of boscalid on postharvest decay of strawberry caused by Botrytis cinerea and Rhizopus stolonifer B. V. Sallato, R. Torres, J. P. Zoffoli and B. A. Latorre* Facultad de Agronomía e Ingeniería Forestal. Pontificia Universidad Católica de Chile. Casilla 306-22. Santiago. Chile Abstract In Chile, gray mold (Botrytis cinerea) and leak (Rhizopus stolonifer) are the major storage diseases of strawberry (Fragaria x ananassa Duch.) that considerably reduce yields and quality, limiting its international commercialization. The effect of preharvest fungicide treatments and postharvest treatments against storage decays was studied. Based on the results obtained, the incidence of B. cinerea and R. stolonifer was significantly lower on ‘Camarosa’ strawberry fruits treated with boscalid or boscalid + pyraclostrobin between blossom and harvest. Similarly, incidence of B. cinerea and R. stolonifer significantly decreased at 5ºC and 20ºC after immersion treatments with boscalid (600 to 700 mg L -1 ) or cyprodinil + fludioxonil (371 + 250 mg L -1 ). These postharvest treatments provided 5 and 15 days protection against these molds when strawberry fruits were stored at 20ºC and 5ºC, respectively. Fenhexamid (750 mg L -1 ) arrested B. cinerea, but it was ineffective against R. stolonifer. Variable results were obtained with iprodione (750 mg L -1 ). Fungicide treatments had no adverse effect on total soluble content, titrable acidity and firmness. Only boscalid + pyraclostrobin affected the external color of the treated fruits. In conclusion, fungicide treatments using new reduced-risk fungicides can be useful to extend strawberry shelf life for over a 15 day period. However, further research is needed to establish a commercial recommendation. Additional key words: boscalid, cyprodinil, fenhexamid, Fragaria, fungicides, pyraclostrobin. Resumen Efecto de boscalid sobre las podredumbres de la fresa en postcosecha causadas por Botrytis cinerea y Rhizopus stolonifer En Chile, el moho gris (Botrytis cinerea) y el moho negro algodonoso (Rhizopus stolonifer) reducen los rendimien- tos y la calidad de la fresa (Fragaria x ananassa Duch.) en pre y postcosecha, limitando su comercialización interna- cional. En este trabajo se estudió la efectividad de tratamientos de campo y postcosecha sobre el desarrollo de podre- dumbres, vida útil y cualidades de la fresa conservada a 5ºC y 20ºC. De acuerdo con los resultados obtenidos, la incidencia de B. cinerea y R. stolonifer en postcosecha fue significativamente menor en fruta proveniente de fresas ‘Camarosa’ tra- tadas, entre floración y cosecha, con boscalid o boscalid + pyraclostrobin. Del mismo modo, fresas ‘Camarosa’ tratadas por inmersión en boscalid (600 a 700 mg L -1 ) o cyprodinil + fludioxonil (375 + 250 mg L -1 ), presentaron menor inciden- cia de B. cinerea y R. stolonifer tanto a 5ºC como a 20ºC. Este tratamiento protegió la fruta durante 5 y 15 días a 20ºC y 5ºC, respectivamente. Fenhexamid (750 mg L -1 ) controló B. cinerea, pero fue inefectivo contra R. stolonifer y con ipro- dione (750 mg L -1 ) se obtuvieron resultados variables. Ningún tratamiento afectó negativamente al contenido de sólidos solubles totales, acidez titulable y firmeza. Sólo boscalid + pyraclostrobin alteró el color externo de la fruta. En conclu- sión, tratamientos con fungicidas con bajo riesgo toxicológico y ambiental permitirían extender la vida útil de fresas al- macenadas. No obstante, se requiere información adicional antes de establecer una recomendación comercial de uso. Palabras clave adicionales: boscalid, cyprodinil, fenhexamid, Fragaria, fungicidas, pyraclostrobin. * Corresponding author: blatorre@uc.cl Received: 06-11-06; Accepted: 31-01-07. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) Spanish Journal of Agricultural Research 2007 5(1), 67-78 Available online at www.inia.es/sjar ISSN: 1695-971X