Callus from hypocotyls of white spruce (Picea glauca [Moench] Voss) was grown on agar under defined conditions with high levels of calcium nitrate. Transfer of callus to liquid suspension cultures and maintenance of suspensions either under a regime of constant temperature and light or under alternating conditions similar to those of a late spring day, affected the content of free sugars, tannins, and aldehydes. Under the alternating conditions the levels of these substances increased greatly compared to those under the constant environment. By contrast, vascularization of cell clumps, which was comparable to the differentiation of hypocotyls in seedlings, was obtained only under constant conditions. Cells at the centre of the clumps developed secondary wall thickenings and bordered pits, and were surrounded by cambial-like initials.
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.
American elm was propagated from callus derived from cell suspension cultures. Suspensions, established from callus, were plated onto agar where, after transfer to a simpler defined medium over 18 months, shoots were produced. Maintenance of high auxin levels yielded roots but no shoots. Shoots were removed from the callus, were treated briefly with indole-3-butyric acid, and transferred to a sphagnum moss – sand mixture for rooting. Other than the absence of cotyledons, plants from callus were comparable to elm seedlings.
Preconditioning of isolates of Beauveria bassiana (Bals.) Vuill. and Metarrhizium anisopliae (Metch.) Sor. with specific insects increases their virulence. An isolate of B. bassiana used two years previously in pathogenicity tests against spruce budworm, Choristoneura fumiferana Clem., required only one passage through this insect to attain 100% mortality in 48 h of incubation, whereas an isolate of M. anisopliae that was not previously used against this insect required four passages to attain the same degree of virulence as B. bassiana. Larvae of Laspeyresia youngana (Kft.), Dasineura rachiphaga Tripp, and Dasineura canadensis Felt were very susceptible to both fungi and 100% mortality was obtained in less than 48 h of incubation. Larvae of Lasiomma anthracina Czerny were much less susceptible. Puparia of both genera of Diptera were more resistant than larvae and required longer incubation to obtain 100% mortality.
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