Identification and Pathogenicity of , , , and Species Associated with Cordon Dieback in Kiwifruit cultivar Hayward in Central Chile.

Dieback symptoms associated with fungal trunk pathogens cause significant economic losses for farmers of kiwifruit and other woody fruit trees worldwide. This study represents the first attempt to identify and characterize the fungal trunk pathogens associated with cordon dieback disease of kiwifruit in central Chile. Field surveys were conducted throughout the main kiwifruit-growing regions in central Chile to determine the incidence and characterize the fungal trunk pathogens associated with cordon dieback of kiwifruit cultivar Hayward through morphological, molecular, and pathogenicity studies. A total of 250 cordon samples were collected and isolations were performed on 2% acidified potato dextrose agar (APDA) plus antibiotics and Igepal. The incidence of kiwifruit cordon dieback ranged between 5% and 85% in all surveyed areas in central Chile. A total of 246 isolates were isolated and identified using culture and morphological features belonging to three fungal taxa: Diaporthaceae spp. ( and ; 133 isolates); Botryosphaeriaceae spp. ( and ; 89 isolates); and Ploettnerulaceae spp. ( and ; 24 isolates). These were identified using phylogenetics studies of the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2) of the rDNA, part of the β-tubulin gene (), and part of the translation elongation factor 1-α gene (-α). Isolates of and were the most virulent, causing internal brown lesions and dieback symptoms in attached green shoots, attached lignified canes, and young inoculated kiwifruits. This report is the first to describe and associated with kiwifruit cordon dieback in Chile. It presents the first description of causing kiwifruit dieback worldwide.