Description:
<jats:p>The following paper presents the results on the determination of the
diversity of species from the Phytophthora genus occurring in the declining
oak stands in Krotoszyn Plateau in Poland. From the 50s of the last century,
significant deterioration of oak health was observed in these stands, and
Phytophthora species were suggested as one of the factors of the decline. In
order to determine the presence of pathogenic organisms from the
Phytophthora genus in these stands, 180 rhizosphere soil samples from three
forest districts throughout the Krotoszyn Plateau were collected and
subjected to the isolation method. Phytophthora species were consistently
isolated from all the sampled stands, and 194 isolates from 111 positive
samples were obtained. However, 150 (77%) and 44 (23%) isolates originated
from the samples taken under the symptomatic and asymptomatic trees,
respectively. All the obtained isolates were morphologically classified
using the light and scanning electron microscopy and divided into
morphological groups. Genomic DNA was isolated from selected isolates
representing each group, ITS regions were amplified and sequence analyses
were performed. In total, four different Phytophthora species were detected,
including P. cactorum, P. plurivora, P. quercina and P. europaea. The most
often isolated species were P. cactorum and P. plurivora. This is the first
report of P. europaea in oak stands in Poland.</jats:p>