Özet:

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.

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