Fungi associated with Tomicus minor on Pinus sylvestris in Poland and their succession into the sapwood of beetle-infested windblown trees

Abstract

The study identified and measured frequency of fungal species associated with Tomicus minor (Hart.) on Pinus sylvestris L. (Scots pine) in Poland. Additionally, fungal succession in P. sylvestris sapwood was investigated during a 12 week period following an attack by this insect. Fungi were isolated from five populations of overwintered adult beetles and their galleries with 59 species of fungi being represented among the 2880 cultures obtained. The most frequent species, Ophiostoma canum (Münch) Syd. & P. Syd., Hormonema dematioides Lagerb. & Melin, and Ambrosiella tingens (Lagerb. & Melin) L.R. Batra, appeared to be specifically associated with T. minor. The succesional changes in species composition during a 12 week period following an attack by T. minor were observed. The pattern of fungal succession in P. sylvestris sapwood essentially agreed with a general scheme of fungal succession in tree sapwood infested by bark beetles. Ambrosiella tingens was the first invader of sapwood and occurred most frequently in its deeper layers. Ophiostoma canum, H. dematioides, and other molds were also often isolated from the sapwood; however, they were most common at a depth of 5 mm during the initial phase of fungal colonization. Later, Ophiostoma canum followed A. tingens in the sapwood invasion.