Causal agents of current season needle necrosis on Trojan Fir (Abies nordmanniana subsp. equi-trojani) growing in the Aladağ mountain range in Bolu Province

• Published in: Australasian plant pathology Vol. 52; no. 4; pp. 317 - 326
• Main Authors: Çakar, Deniz, Şimşek, Seçil Akıllı, Çömez, Aydın, Maden, Salih
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-07-2023; Springer Nature B.V
• Subjects: Abies nordmanniana; Agriculture; Alternaria alternata; Asymptomatic; Aureobasidium; Biomedical and Life Sciences; Botrytis cinerea; Colletotrichum; Didymella; Ecology; Entomology; Epicoccum; Fungi; Inoculum; Life Sciences; Mountains; Necrosis; Needlecast; Original Research Article; Pathogenicity; Pathogens; Pine needles; Plant Pathology; Plant Sciences; Rhizosphaera; Spraying; Sydowia polyspora; Turkey; Needle necrosis; sp; CSNN
• ISSN: 0815-3191; 1448-6032
• DOI: 10.1007/s13313-023-00921-z

In the spring of 2021, Current Season Needle Necrosis (CSNN) symptoms were observed on about 60% of the needles together with needle cast on Trojan Fir (
Abies equi-trojani
) growing in Aladağ Mountain range near Bolu province of Turkey. From the 200 symptomatic needles, obtained from 10 branch samples collected from 10 different trees in the years 2021 and 2022 each, the following eight fungi were recovered in the respective percentages;
Didymella
sp. (25.5%),
Sydowia polyspora
(25%),
Alternaria alternata
(14.5%),
Aureobasidium
sp. (1.5%),
Epicoccum
sp. (1.5%),
Colletotrichum fioriniae
(0.5%),
Botrytis cinerea
(0.5%) and
Rhizosphaera macrospora
(0.5%). Isolations were made from 200 asymptomatic needles collected from Kastamonu (150) and Bolu (50) provinces and the following fungi were recovered;
Didymella
sp. (30%),
A. alternata
(8.5%),
S. polyspora
(1%),
Epicoccum
sp. (1%) and
Rhizopus
sp. (0.5%).
S. polyspora
was recovered from only the asymptomatic fir needles collected from Bolu province. Pathogenicity of the three potential pathogenic fungi were tested on the needles of healthy fir saplings by spraying spore suspensions and
S. polyspora
produced necrosis on 37% of the intact needles, following
Didymella
sp. with 23% and
C. fioriniae
21%. Mix inoculum of the three fungi formed necrosis on 30.5% of the fir needles. Pathogenicity of
S. polyspora
was also tested on wounded needles and it produced higher rates of infection than the healthy ones. Pathogenicity of
S. polyspora, Didymella
sp.,
C. fioriniae
were tested on barks of 3 years old fir saplings and only the former produced significant size of necrosis, 3.16 cm in 28 days. Occurrence of CSNN on Trojan fir was first recorded in Bolu province of Turkey with this study.