Almond Decline Caused by Phytophthora megasperma in Southeastern Anatolian Region of Turkey

Year 2016, Volume: 45 Issue: 1, 13 - 20, 30.09.2016

İlker Kurbetli , Ajlan Yılmaz

Abstract

Decline symptoms were observed on young almond trees
in commercial orchards of Adıyaman province of Turkey in 2013. Symptoms in
affected trees included yellowing of foliage, cankers on roots, crowns and stem
base, and dieback. An isolate of Phytophthora
sp. was consistently isolated from necrotic tissues from taproots and crowns of
symptomatic trees. The pathogen was identified as Phytophthora megasperma
based on morphological features and DNA sequence of the internal transcribed
spacer (ITS) region. Pathogenicity of the isolates was tested by shoot and stem
inoculation, as well as soil infestation on almond saplings. Typical canker
lesions developed on excised shoots after two weeks. Lesions also occurred on
stems of scion and rootstock four weeks later. At the end of the soil
infestation test, cankers covered the whole roots four months after
inoculation. Eleven isolates of P.
megasperma were assayed for sensitivity to mefenoxam. All isolates were
found to be sensitive to mefenoxam with EC₅₀ values less than 1 μg
mL^-1.

Keywords

Prunus dulcis, almond decline, pathogenicity

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