Preliminary results of auxin and brassinosteroid application on ‘Candidatus Phytoplasma prunorum’ infected plants

In this study the effect of foliar application of brassinosteroid (24-epibrassinolide, EBR) and auxin (indole-3-butyric acid, IBA) was tested on ‘Candidatus Phytoplasma prunorum’ (CP) presence and symptom manifestation in CP infected stone fruit trees. Two CP inoculum sources, apricot cultivars Poyer and Hargrand and two rootstocks, peach GF-305 and apricot M-VA-2, were used. Based on the results, phytohormones did not affect the concentration of CP in the treated plants. Leafroll symptom manifestation was increased after IBA treatment in almost all cases, while inconsistent results were obtained for the chlorosis symptoms in cultivars, whereas rootstock chlorosis symptoms decreased after EBR and IBA treatments. However, in most of the cases, the results were not significantly different.