Canadian Forest Service Publications
Stem incorporation of systemic insecticides to protect white spruce seed trees. 1989. Fogal, W.H.; Lopushanski, S.M. Forestry Chronicle 65(5): 359-364.
Issued by: Northern Forestry Centre
Catalog ID: 23481
Availability: Order paper copy (free), PDF (request by e-mail)
White spruce trees were injected with a liquid formulation of dicrotophos (0.6 g Al/cm DBH) to evaluate the effect of injection times on cone and seed damage by insects. Injections of liquid formulations of dicrotophos (1.1 g Al/cm DBH) and oxydemetonmethyl (0.7 g Al/cm DBH) (approximately four days after the peak of flowering) were evaluated for control of defoliation and cone and seed damage by insects. Implants of a soluble powder formulation of acephate (0.5 and 1.0 g Al/cm DBH) (approximately two weeks after the peak of flowering) were evaluated for control of cone and seed damage. A single injection of dicrotophos reduced cone damage for up to four weeks after the peak of flowering by insects that oviposit and feed after pollination (seed moth, cone maggot, cone-axis midge, and seed inhabitants) whereas damage by insects that begin feeding before pollination was not reduced by single injections after pollination. Dicrotophos and oxydemetonmethyl reduced defoliation by spruce budworm at upper, middle, and lower crown levels for two seasons following injection. In the treatment year, these injections reduced the proportions of cones damaged by insects that feed after pollination whereas damage by insects that feed before pollination was not reduced; cone seed counts were increased 558% by dicrotophos and 267% by oxydemetonmethyl. In the season after injection the proportion of cones damaged by budworm was reduced by both insecticides while seed inhabitant damage was reduced by dicrotophos. Neither insecticide reduced damage by other insects; nonetheless, cone seed counts were increased 90% by dicrotophos and 115% by oxydemetonmethyl. In the year of treatment, implants of acephate reduced the proportions of cones damaged by seedmoth but not other insects whereas, in the season after implanting, they were effective against coneworm, seed moth, cone maggot, and seed inhabitants.