Abstract

The influence of five nursery field management treatments including alternative, sustainable practices (ie. companion crops, allelopathic cover crops/mulches) on the incidence of stem cankers caused by Nectria cinnabarina (Tode: Fr.) Fr. on ‘Skyline’ thornless honeylocust (Gleditsia triacanthos L. var. inermis Willd. ‘Skyline’) was monitored in Minnesota. Although considered a stress related disease, field management treatments that reduced tree vigor (ie. growth), decreased susceptibility to attack by N. cinnabarina while treatments which promoted vigorous growth increased susceptibility. The observed vulnerability of honeylocust trees to N. cinnabarina may be related to plant cold hardiness and subsequent winter injury to root and crown tissue as affected by nursery field management treatment. Moisture stress late in the growing season, resulting from root injury during the previous winter, mechanical root injury from cultivation, and high summer soil temperatures may have increased susceptibility to N. cinnabarina for honeylocust trees grown in bare soil field production systems. Moisture stress in late summer may not be reflected in plant growth, but may increase the susceptibility of honeylocust trees to attack by N. cinnabarina.