Evaluation of the biological control agent Rotstop in controlling the infection of spruce and pine stumps byHeterobasidionin Latvia

Biological protection of conifers against Heterobasidion infection – interaction between root-rot fungus and Phlebiopsis igantea

“…Also in Sweden, Rotstop showed lower efficacy values compared to native isolates of P. gigantea (Berglund et al, 2005). However, in Experiments 1 and 2 in depths of 3 and 9 cm, mean efficacy values of Rotstop (mean from all analysed sectors) in spruce (61.5%) and pine (90.5%) were rather similar to values obtained in previous investigations conducted in Latvia: 89% in spruce and 95% in pine -efficacy values calculated based on wood occupied by Heterobasidion (Kenigsvalde et al, 2016). Mean efficacy of Latvian isolates of P. gigantea in Experiments 1 and 2 in depths of 3 and 9 cm (mean from all analysed sectors) was 83.6% in spruce and 88.7% in pine.…”

“…Area occupied by isolates of P. gigantea, % from total sector area (Kenigsvalde et al, 2016). The results obtained with these two methods can differ more than two times (Thor & Stenlid, 2005).…”

“…The biological control agent Rotstop ® ('Rotstop F', Verdera Oy, Finland), composed of spores of the nonpathogenic wood-decay fungus Phlebiopsis gigantea (Fr.) Jülich, is used for stump protection also in Latvia, where its efficacy is similar to efficacy in other countries (Kenigsvalde et al, 2011;Kenigsvalde et al, 2016). However, research in Sweden has shown that sometimes native isolates of P. gigantea have higher efficacy than Rotstop, which contains a Finnish isolate of P. gigantea (Berglund et al, 2005).…”

Infection of pre-commercially cut stumps of <i>Picea abies</i> and <i>Pinus sylvestris</i> by <i>Heterobasidion</i> spp. – a comparative study

“…It is known, that although airborne spores of the fungus have potential to spread over 100s of kilometres, prevailing majority of them land in the vicinity of a sporocarp (Rishbeth 1951;Stenlid 1994). That spruce stumps are more prone to Heterobasidion than pine has been previously observed in another Latvian study (Kenigsvalde et al 2016), where in mixed stands primary infections by Heterobasidion were observed in 81-85% of spruce stumps, compared with 0-14% of pine. More frequent infections to larger stumps have also been previously reported both in spruce (Paludan 1966;Solheim 1994;Bendz-Hellgren and Stenlid 1998) and pine (Rishbeth 1951).…”

“…Grid squares where conidiophores were found were marked on the disc. The number of marked squares was counted, and the surface area (cm 2 ) of wood colonized by Heterobasidion on stump cross-sections was estimated (Kenigsvalde et al 2016).…”