Annosus root disease

Caused by several Heterobasidion sp. fungi, mainly Heterobasidion annosum

Annosus root disease is caused mainly by annosum root rot. There are two annosum root rot species in Latvia – Heterobasidion annosum, which infects mainly pines, and Heterobasidion parviporum, which infects mainly spruce and larch. Fungal root rot causes trees to weaken, fall over in the wind, be attacked by trunk pests and tree decline, as it interferes with the transport of water and nutrients in the plants. Root rot spreads when the roots of diseased trees come into contact with the roots of healthy trees, and the hyphae of the fungus move to and infect healthy trees. Basidiocarps of the fungus are shaped like half-plates and grow one on top of the other. They are found both on the trunks of living trees and on dead trees and stumps.