Assessing the virulence of ophiostomatoid fungi associated with the pine-infesting weevils to scots pine Pinus sylvestris L. seedlings

The pine-infesting weevils are known to be effective vectors of ophiostomatoid fungi. To understand more about fungal virulence of these fungi, inoculation studies were conducted on Scots pine (Pinus sylvestris L.). Two-year-old seedlings were wound-inoculated with one of eleven ophiostomatoid fungi associated with pine-infesting weevils. After 11 weeks, a darkened lesion, extending from the point of inoculation, was observed in all species, except for Ophiostoma cf. abietinum Marm. & Butin, Ophiostoma quercus (Georgev.) Nannf., and Sporothrix inflata de Hoog. Seedling mortality was observed in seedlings inoculated with Leptographium truncatum (M.J. Wingf. & Marasas) M.J. Wingf., Leptographium lundbergii Lagerb. & Melin, Leptographium procerum (W.B. Kendr.) M.J. Wingf., Grosmannia radiaticola (J.J. Kim, Seifert & G.H. Kim) Zipfel, Z.W. de Beer & M.J. Wingf., Ophiostoma floccosum Math.-Käärik, Ophiostoma minus (Hedgc.) Syd. & P. Syd., and Ophiostoma piliferum (Fr.) Syd. & P. Syd. Ophiostoma minus and L. truncatum caused the largest lesions and sapwood blue-stain in Scots pine. Grosmannia radiaticola, Ophiostoma piceae (Münch) Syd. & P. Syd., O. floccosum, O. piliferum, L. lundbergii,and L. procerum produced significantly smaller lesions and sapwood blue-stain than O. minus and L. truncatum, while O. cf. abietinum, O. quercus and S. inflata did not cause any lesions.