Poster Session: Diseases of Plants - Disease Detection and Diagnosis
432-P
Detection of Speck rot on Pink Lady apple fruit in the Maule Region in Chile.
G. A. DIAZ (1), B. A. Latorre (2), J. P. Zoffoli (2), M. Caceres (1), R. Mendez (1), M. Lolas (1)
(1) Universidad de Talca, Talca, Chile; (2) Pontificia Universidad Catolica de Chile, Santiago, Chile
Chile has a production area of 37,207 Ha of apples. The fungal diseases is one of the major problems for Chilean industry of apple. Recently in Washington, USA, it has been described speck rot or rubbery rot, a new fungal disease that affect to apples in the orchard and in the cold storage caused by Phacidiopycnis washingtonensis. Speck rot affecting of Pink Lady apples were observed during cold storage and in apples on the floor of orchards in Region of Maule in Chile during 2014 and 2015. Speck rot was characterized by an initial light brown skin discoloration that progressed to a black skin discoloration, with a firm rubbery textured. Small fragments were collected from diseased tissues and aseptically placed on PDA. Gray colonies with aerial mycelia and showing alternating growth rings were observed. The conidia were smooth, unicellular, hyaline, ellipsoid to lacriform with flattened ends, and measured 6.6 x 3.6 µm. The ITS region of rDNA was amplified using primer ITS4/ITS5. Based on morphology and phylogenetic analyses, this fungus was identified as P. washingtonensis. All inoculated apple fruits developed necrotic lesions and the re-isolations were 100% positive to P. washingtonensis. Virulence was tested on different cultivars of apples. The isolates were sensitive to the three commonly used fungides. To our knowledge, this study is the first description and partial characterization of isolates of P. washingtonensis causing speck rot in Chile