ISHS Acta Horticulturae 715: VIII International Symposium on Vaccinium Culture
CRANBERRY PESTS AND DISEASES IN NEW ZEALAND |
| Authors: | S.A. Miller, N. Patel, C.J. Stanley |
| Keywords: | Vaccinium macrocarpon, fruit rots, pathogens, yield, climate |
| Abstract:
The cranberry industry in New Zealand is relatively new with plantings restricted to a large commercial development located on the west coast of the South Island and two research sites. Small volumes of fruit have been harvested over the past 4 years and it appears that parts of New Zealand would be able to support a viable cranberry industry. Research to date has focused on clarifying factors that are likely to affect plant establishment and fruit quality. In this work we carried out a survey of three geographically separated sites to compare regional differences in the incidence of pest and disease problems that are likely to be encountered by cranberry growers. Few insect pests and no virus or bacterial pathogens were identified in this work. Declana floccosa (Geometridae: Ennominae) has been found feeding on cranberry foliage on the commercial west coast site, but severe defoliation has not been noted. D. floccosa is one of two extremely abundant polyphagous endemic geometrids, both of which are found on many hosts throughout New Zealand. Eggs of one of the pentatomid bugs have been found on cranberry twigs at the same site, possibly a predatory bug that preys on caterpillars. In contrast, fungal diseases were more prevalent, with a wide variety of pathogens identified, particularly at the northern site. Stem dieback was common in new plantings on this site and resulted in large dead areas in the beds. The dominant pathogen detected in the shoots of sawdust-grown plants was Pestalotiopsis maculans, with a number of other fungi also present including Botryoshaeria parva, Colletotrichum acutatum, Fusarium oxysporum, Glomerella cingulata, and Phomopsis spp. The major root pathogen identified was Fusarium oxysporum. Fruit rots, both pre- and post- harvest were also more common at the northern site, due to a combination of cool wet conditions in spring that favoured infection of the flowers, and high humidity over the fruit ripening period. The dominant pathogen isolated from infected fruit was Colletotrichum acutatum. Yield losses of up to 50% were recorded on some varieties. Options for successful management of cranberry diseases are discussed. | |
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