Plant Pathology: Extension: Plant Disease Library

Nectria

Important diseases:  Trunk canker of Hardwoods, Coral spot canker, Stem canker and rot of Bean and Gerber Daisy.

Nectria is an Ascomycete meaning that it produces it spores within a sac. Nectria is the sexual stage of several asexual or "imperfect" fungi including Fusarium, Cylindrosporium, and Tubercularia.


Nectria infection causes crown and lower stem rots. Infected plants will often wilt and die. Branch and stem cankers caused by Nectria are small, depressed or flattened areas of bark near small wounds or at the base of dead twigs or branches. Trees eventually form successive rolls of callus around cankers.

Nectria produces brightly colored (orange to red) perithecia (fruiting structures) on the surface of infected tissue. Spores within asci (sac-like structures) are produced within the perithecia. Typically, eight ascospores are present within each ascus. Ascospores are clear and their size may vary depending upon Nectria species. Certain species produce 2-celled ascospores with a slight constriction between the two cells.



Imperfect stages of the Nectria may include Fusarium which is commonly seen in associated with the perithecia of Nectria.