Acceptability of thiram-treated conifers to snowshoe hares

Abstract

During March of the first winter and November of the subsequent fall following application of thiram to white spruce (Piceaglauca (Moench) Voss), treated twigs provided protection against snowshoe hare (Lepusamericanus Erxleben) depredation (P = 0.0001). Both experiments were conducted at Edmonton, Alta., with animals under restricted-feed conditions. In March, thiram-treated trees were more resistant to hare clipping of apical stems (P = 0.0001) and buds (P = 0.001), and barking of stem areas (P = 0.0001) compared with browsing of treated apical stems (P = 0.058) and buds (P = 0.026), and barking of stem areas (P = 0.013) in November once current annual growth had emerged and substantial weathering had occurred. Height of stems removed also differed between treatments during November (P = 0.0001). Overall, thiram treatments may help increase conifer survival in reforestation areas supporting snowshoe hares if used in concert with other deterrent means until more effective control measures are developed.