3. Doktoritööd
Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/7081
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Sirvi 3. Doktoritööd Autor "Børja, Isabella (opponent)" järgi
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Kirje Interaction between large pine weevil (Hylobius abietis L.), pathogenic and saprotrophic fungi and viruses(Eesti Maaülikool, 2017) Drenkhan, Tiia; Voolma, Kaljo; Sibul, Ivar; Kasanen, Risto; Børja, Isabella (opponent)The aim of the doctoral thesis was to investigate the survival ability of pathogenic fungi Heterobasidion spp. and Diplodia sapinea and the saprotrophic fungus Phlebiopsis gigantea and viruses, after passing through the digestive tract of large pine weevils (Hylobius abietis L.). In laboratory experiments the growth of Heterobasidion spp. (infected with viruses HetPV2-pa1, HetPV4-pa1, HetRV6-pa17) and strains of P. gigantea (virus infected strain PgLV-1) and virus free strain (Rotstop®) were examined. Pine weevil adults that were potentially infected by D. sapinea were also investigated. The results of the study revealed that the large pine weevil is indeed able to carry viable spores of pathogenic and saprotrophic fungi, as well as viruses, through their digestive tract. The viruses may occur within hosts (fungi) without causing any consequences or they can also have a negative effect, which manifests through inhibited fungal growth or virulence to the host. The effect of viruses on Heterobasidion spp. can be different: exhibiting no symptoms or, under suitable conditions (i.e. new host), interfering with the fungal growth. After passing through the large pine weevil, the P. gigantea virus infected strain has lower viability and growth rate compared to the same species strain without viruses. While P. gigantea is used to produce the preparation Rotstop® for the treatment of conifer stumps against Heterobasidion spp., it is essential to ensure that a virus free strain of P. gigantea was utilized. When using a virus infected strain of P. gigantea, the effectiveness of protection may be lower. D. sapinea is a pathogen on Scots pine (Pinus sylvestris). D. sapinea will spread over short distances via spores, but the fungus can spread much more extensively and intensively by adult pine weevils. The significance of large pine weevils in managed forest can increase in the future, since the adult weevils are able to transport viable spores of different fungi through their digestive tract.