|Authors: ||T.L. Bradshaw, L.P. Berkett, R.E. Moran, M.E. Garcia, H.M. Darby, R.L. Parsons, S.L. Kingsley-Richards, M.C. Griffith, S.C. Bosworth, J.H. Görres|
|Keywords: ||'Ginger Gold', 'Honeycrisp', 'Liberty', 'Macoun', 'Zestar!', integrated pest management, apple scab, rust, fruit rots, mites, Lepidoptera pests|
The results presented summarize six years of seasonal data of disease symptoms and arthropod infestations and/or damage on foliage and fruit on five organically-managed apple cultivars ('Ginger Gold', 'Honeycrisp', 'Liberty', 'Macoun', and 'Zestar!') grown in a newly planted orchard (Orchard 1) and a top-grafted established orchard (Orchard 2). Significant differences were found among cultivars for all assessed diseases in the study. 'Ginger Gold' and 'Macoun' had significantly greater foliar and fruit scab than 'Honeycrisp' and 'Liberty' in both orchard systems.
The low incidence of scab on 'Honeycrisp' foliage and fruit and 'Zestar!' fruit was not statistically different than the scab-resistant cultivar 'Liberty' on which no scab was observed.
Apple rusts were present on foliage, with 'Ginger Gold' and 'Honeycrisp' having the highest incidence and 'Zestar!' having the lowest in both orchards. 'Macoun' and 'Liberty' ranked the highest in the percentage of fruit without arthropod damage in both orchard systems but differences among the other cultivars were not distinct.
Management of lepidopteran pests of fruit was a major challenge on all cultivars over the years of the study.
European red mite incidence was high in both orchards, but only in Orchard 2 were there differences among cultivars, where 'Ginger Gold' and 'Honeycrisp' had greater incidence than 'Macoun' and 'Zestar!', with 'Liberty' not different from any other cultivar.
Rankings of disease and arthropod damage and incidence were similar in both orchards, which suggests that the orchard systems were not a major factor in pest management among the cultivars.
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