Studies on pine needle blight pathogens in Europe and USA
The aim of a recent study was to determine the causal agents of pine needle blight associated with Lecanosticta acicola (EPPO A2 List), Dothistroma pini and Dothistroma septosporum (EU Annexes)] in six European countries (Bulgaria, Ireland, Latvia, Portugal, Russia, Spain) and in Arkansas (US). Samples of pine needles showing necrotic bands were collected in 2015/2016/2017 from several pine species (P. elliottii, P. mugo, P. nigra, P. radiata, P. sylvestris, P. thunbergii) in forest plantations, arboreta and from ornamental trees. Fungal isolates were identified using molecular methods (PCR tests). Results obtained were as follows.
Lecanosticta acicola is reported for the first time from Ireland and Portugal. In Ireland, the fungus was detected in 2 samples which had been collected from the JF Kennedy Memorial Park and Arboretum (county of Wexford) on P. sylvestris and P. mugo. In Portugal, L. acicola was detected in 1 sample collected from Agualonga (Norte region) on P. radiata. In Russia, the presence of L. acicola was confirmed on the Black Sea coast in a sample of P. thunbergii collected from Sochi. In Latvia, the fungus was recovered again in 2016 from P. mugo at the only site (National Botanical Garden, Salaspils) where it had previously been reported (EPPO RS 2012/168) 4 years after eradication measures were undertaken.
Dothistroma pini was detected in a sample of P. nigra in Spain (Puente de Montaña, Aragon) and in a sample of P. elliottii from Arkansas (Little Rock).
Dothistroma septosporum is reported for the first time from Ireland. It was isolated from samples of P. sylvestris and P. radiata collected from the JF Kennedy Memorial Park and Arboretum (Wexford county), Newcastle West (Limerick county), and Ballydesmond (Cork county). In Spain, D. septosporum was detected in samples of P. nigra and P. sylvestris collected from Comunidad Valenciana (in Boixar and Fredes). In Bulgaria, D. septosporum was detected in samples of P. nigra and P. sylvestris collected from Panichkovo (Kardzhali province).
Sources
Mullett MS, Adamson K, Bragança H, Bulgakov TS, Georgieva M, Henriques J, Jürisoo L, Laas M, Drenkhan R (2018) New country and regional records of the pine needle blight pathogens Lecanosticta acicola, Dothistroma septosporum and Dothistroma pini. Forest Pathology 48. e12440. https://doi.org/10.1111/efp.12440