Document Type
Article
Source
Journal of Plant Diseases and Protection
ISSN
1861-3829
Volume
122
Issue
5
First Page
207
Last Page
214
Publication Date
2015
Department
Natural Sciences and Mathematics
Abstract
The effects of four commercially available bio-active compounds on the infection rates, symptom expression and growth rates of apple trees (Malus × domestica Borkh.) cv. Golden Delicious infected with ‘Candidatus Phytoplasma mali’ (the so-called Apple Proliferation phytoplasma or AP) were tested over a three-year period under controlled conditions. Post-infection treatments using Bion® (active ingredient: Acibenzolar-S-Methyl), Messenger® (Harpin protein), Regalis® (Prohexadione-Ca) and Dormex® (Cyanamide) had no significant effect on infection rates. Terminal growth of apple trees (grown as one-shoot pruned trees) was increased significantly by AP infection; Prohexadione-Ca was the only compound which had a significant (inhibiting) effect on the growth of both infected and non-infected apple trees. Acibenzolar-S-Methyl and Harpin had no significant effects on symptom expression. AP symptoms were masked during summer by Prohexadione-Ca, which caused severe growth abnormalities. Cyanamide changed the seasonal appearance of AP symptoms: while symptoms were delayed compared to the untreated control the first two years (2008 and 2009), symptoms appeared earlier the third year (2010). Differences in symptom expression leveled off later in the vegetative season, and no significant difference was found in October.
Rights
Copyright © Eugen Ulmer KG, Stuttgart