J. Auger, I. Pérez, M. Esterio, R.A. Fullerton
Growing of ZESPRI® Gold kiwifruit, Actinidia chinensis Planch. ‘Hort16A’, under licence in Chile began in 2003. By 2006, 150 ha of ‘Hort16A’ had been established, and vines started dying within 2 years. By the end of the 2008-2009 growing season, as many as 80% of the plants in several orchards had died. The disease was characterized by a sudden wilting and dieback of plants any time during the growing season. In the spring, entire plants or parts of plants failed to break bud. In others, the buds broke, but juvenile leaf clusters then wilted and died. On severely affected plants, scion water shoots wilted and died. The disease was apparently most severe in sites that had been planted to Gold kiwifruit immediately after removal of apple, pear, citrus, or grape. Orchards planted following long-term maize, wheat, or grass culture were almost disease free. A fungus was consistently isolated from symptomatic vascular tissue. On the basis of morphological characteristics and by sequencing part of the Internal Transcribed Spacer (ITS) region with primers ITS1 and ITS4, the fungus was identified as Verticillium albo-atrum Reinke & Berthier. To complete pathogenicity tests, 20 healthy, one-year-old A. deliciosa (A. Chev.) C.F. Liang & A.R. Ferguson ‘Hayward’, A. chinensis ‘Hort16A’ and A. chinensis ‘Hort 16A’/A. deliciosa ‘Bruno’ seedling rootstocks, were inoculated. Eight weeks after inoculation, typical wilting and dieback symptoms developed on 90% of the plants. Control plants dipped in sterile distilled water remained healthy. Verticillium wilt has never been reported on kiwifruit (A. deliciosa) in Chile. V. albo-atrum has a rather narrow host range and is mainly reported as a pathogen on alfalfa, hop, soybean, tomato, and potato. This is the first report of V. albo-atrum causing wilt and dieback on Gold kiwifruit (A. chinensis) ‘Hort16A’.
Auger, J., Pérez, I., Esterio, M. and Fullerton, R.A. (2011). OUTBREAK OF A LETHAL WILT FORM OF GOLD KIWIFRUIT, ACTINIDIA CHINENSIS 'HORT16A' IN CHILE. Acta Hortic. 913, 473-479
DOI: 10.17660/ActaHortic.2011.913.63
Verticillium albo-atrum, wilting symptoms, dieback symptoms, pathogenicity test, Internal Transcribed Spacer

Acta Horticulturae