Spruce Beetle Suppression in Trap Trees Treated with Cacodylic Acid123

Abstract

Engelmann spruce trees were frilled by hand hatchet and Silvisar® 510 (dimethylarsinic acid) was added to the frills at periodic intervals before the peak flight. period of the spruce beetle in an effort to produce lethal traps. Some trees were felled at. periodic internals after treatment and some were left standing. An evaluation was made 12–13 months after treatment. Number of attacks in samples from trees treated in mid-June and felled 2 weeks later was not significantly different than that from check trees. However, only a few live spruce beetle larvae and pupae were found in samples from trees treated at this time whereas significant numbers were found in samples from check trees.