Fusarium subglutinans f. pini
English names: Pitch canker of pine
Nordic names: Fyrreharpikskræft (DK)
Major host plants
G. circinata infects Pinus spp.. Pseudotsuga menziesii is infected occasionally.
The symptoms of pitch canker can vary among different hosts and the environments in which they are grown. The symptoms include bark cankers, wilting, fading of needles on branch tips, large amounts of resin around the infection site. Needles become yellow, then red and fall from branch; infected wood is slightly sunken, honey coloured, with resin. Trees can suffer crown dieback or may die. The pathogen also causes a damping off of seedlings in nurseries.
The origin and spread of G. circinata seems obscure. The fungus is probably native in North America. In 2005 the disease was identified in the EPPO region (Spain).
A map can be downloaded from EPPO's website. See instructions here.
G. circinata invades its host through wounds. The pathogen can infect a susceptible host at any stage of the tree’s life cycle: flower, seed, seedling, and mature tree, as well as many different parts of the hosts: shoots, branches, cones, seeds, and exposed roots. Naturally occurring wounds as well as branch removal and other mechanical damage can all provide entry sites for spores. Small (less than 3 mm), salmon-orange, wart like fruiting bodies of the anamorph stage are produced on dead or dying branches, most typically in needle scars. These fruiting bodies produce large masses of conidia which may infect new trees. Infection occurs most commonly during late summer and fall. The fungus can grow and persist in soil and may act as a root infecting pathogen. It is also found in seeds and on seed coats. The fungus is able to survive for more than 12 months in resin impregnated tissues in logs. Free moisture may be necessary for successful infection of wounds. The pathogen grows poorly below 10 °C.
The fungus may be airborne, soil borne, dispersed in rain splash, or it may be vectored by flying insects. Over long distances, it can be carried by consignments of pine seeds, or by plants for planting. The pathogen may be transmitted by infected wood as well, especially as small branches or bark, whereas debarked round wood or sawn timber are considered to be of less importance in the spread of the fungus.
Detection and inspection
Identification relies on the presence of characteristic symptoms and on isolation and culturing of the fungus.
Pest status and importance
G. circinata is damaging to many pine species and one at particular risk is Monterey pine (Pinus radiata). The disease probably presents the greatest risk to forest nurseries in Europe.
Source of information
See further information here:
Author: Eigil De Neergaard and Elise T. Yamamoto Buch
Editor: Dorthe Vestergaard