Fruiting and sporulation of Thekopsora and Chrysomyxa cone rusts in Picea cones and Prunus leaves

• Published in: Forest Pathology
• Main Authors: Kaitera, J., Hiltunen, R., Kauppila, T., Pitkäranta, M., Hantula, J.
• Other Authors: Sieber, T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Padus; Northern Finland
• Online Access: http://dx.doi.org/10.1111/efp.12114; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fefp.12114; https://onlinelibrary.wiley.com/doi/pdf/10.1111/efp.12114

Summary Natural fruiting and sporulation of cone rusts were investigated in cones of Picea spp. and leaves of Prunus spp. in a botanical garden in northern Finland in 2007–2012. Thekopsora areolata was the most frequent cone rust in Picea abies cones, where it colonizes the host tissues and hinders normal seed development. Aecia of T. areolata were also common in cones of Picea engelmannii and occasionally in cones of P. glauca . Aecia of T. areolata sporulated in cones that were at least one year old. Chrysomyxa pirolata, another pathogenic cone rust, fruited and sporulated annually but infrequently in current‐year cones of P. abies . The spruce needle rust, Chrysomyxa ledi , fruited and sporulated commonly in current‐year cone scales of P. abies , P. omorika and P. glauca , while P. rubens , P. mariana and P. pungens appeared to be resistant during the study period. Chrysomyxa ledi did not affect seed development in infected cones. Uredinia of T. areolata frequently occurred on leaves of 41 Finnish and Russian cultivars, varieties or subspecies of Prunus padus L. ssp. badus and ssp. borealis and Pr. virginiana both in the botanical garden and in the field, while 13 exotic Prunus spp. lacked rust fruitbodies. All the Pr. padus cultivars were highly susceptible to T. areolata , thus, spreading the rust efficiently to surroundings. This is the first report of aecia of T. areolata in cones of P. engelmannii and P. glauca , and those of C. ledi in cones of P. omorika and P. glauca . Molecular identification confirmed the presence of T. areolata and C. pirolata on all hosts, and all samples of C. ledi belonged to the C. ledi‐rhododendri complex.