Undiluted Silvisar 510® (cacodylic acid) was applied in a frill girdle to Engelmann spruce, Picea engelmanni Parry. 1.5 feet above the ground level in late spring. The trees were felled 9 to 14 days later and tested as lethal trap trees. The treated trees were fatal to Dendroctouns rufipennis (Kirby), and prevented brood development. Hectic mortality was equal in all portions of the bole. The number of attacks did not differ between treated and control trees. and there was no repelling effect after the attacks had occurred. Spruce beetles died slowly and constructed abnormally shaped and short egg galleries. Results in artificially infested bolts from the trap trees were the same. The water content in treated trees was not significantly different from that in untreated trees. Blue stain development was very light in the treated trees and heavy in the untreated trees. Ips pilifrons Swaine, Ploygraphus rufipennis (Kirby), and Scierus annectens LeConte, had some mortality in the treated trees. Trypodendron lineatum (Oliver) was attracted to the treated trees, but their development was not affected.
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Frye et al. (1971) studied this question.