Foliar and cortical monoterpenes in Sitka spruce: potential indicators of resistance to the white pine weevil, Pissodesstrobi Peck (Coleoptera: Curculionidae)

1987 ◽  
Vol 17 (7) ◽  
pp. 740-745 ◽  
Author(s):  
J. E. Brooks ◽  
J. H. Borden ◽  
H. D. Pierce Jr.

To determine whether a resistant chemotype to the white pine weevil, Pissodesstrobi Peck, could be identified, the relative composition of monoterpenes in weevil-susceptible Sitka spruce, Piceasitchensis (Bong.) Carr., was compared to that in apparently resistant trees. Foliar and cortical analysis of trees from Green Timbers Nursery in Surrey, Nootka Island, Sayward, and the Nass River Valley, B.C., revealed significant differences between 38 resistant and 60 susceptible trees. The foliage of resistant trees, compared with that of susceptible trees, had significantly lower amounts of isoamyl isovalerate at three sites and lower amounts of isopentenyl isovalerate at one site. Amounts of a α-pinene, β-pinene, camphene, and camphor were significantly higher in some resistant trees, but these differences were not consistent between sites. Myrcene, β-phellandrene, and limonene levels were much higher in the cortex of susceptible trees than the resistant trees from the Nass River and Green Timbers Nursery. Thus none of the monoterpenes, singly or in combination, is a consistent indicator of resistance to the white pine weevil. The two isovalerates could possibly be used as indicators of resistance. However, a broader spectrum of resistance characteristics should be employed if breeding for resistance is desired.

1996 ◽  
Vol 74 (4) ◽  
pp. 599-606 ◽  
Author(s):  
Elizabeth S. Tomlin ◽  
John H. Borden ◽  
Harold D. Pierce Jr.

Cortical resin acids were analyzed both quantitatively and qualitatively among 10 provenances and 11 genotypes of Sitka spruce, Picea sitchensis Bong (Carr.), putatively resistant to the white pine weevil, Pissodes strobi (Peck), and compared with susceptible trees. Trees in 5 of the 11 resistant genotypes had significantly greater amounts of cortical resin acid than susceptible trees. Of seven individual acids analyzed, pimaric, isopimaric, levopimaric, dehydroabietic, abietic, and neoabietic acid, but not palustric acid, were found in significantly greater amounts in trees from resistant than susceptible provenances. Eighteen percent of the variation in resin acid content could be accounted for by variation in the capacity of cortical resin ducts, indicating that the other 82% of variation is a result of differences in resin acid concentration in the resin. Trees with very high resin acid levels may have a greater capacity for resinosis than susceptible trees, may deter feeding, or may produce resin that is toxic to eggs and larvae. Canonical discriminant analysis revealed that several resistant clones, particularly two from the Kitwanga provenance, could be distinguished from others on the basis of their resin acid profiles. Because it separated trees on the basis of genotype, but not according to degree of resistance, canonical discriminant analysis may be more useful in "chemotyping" trees than in screening for resistance. Keywords: Picea, cortex, resin acids, Pissodes strobi, resistance.


1980 ◽  
Vol 112 (12) ◽  
pp. 1259-1270 ◽  
Author(s):  
R. I. Alfaro ◽  
J. H. Borden

AbstractThe predatory behavior of Lonchaea corticis Taylor on the white pine weevil, Pissodes strobi Peck, in Sitka spruce, Picea sitchensis (Bong.) Carr., was studied by temporal sampling and dissection of terminal leaders, and by laboratory experiments. L. corticis oviposition occurred when mining P. strobi larvae were consolidating the feeding ring, an event that segregates the weevil larvae into healthy front-feeders and weak, starving "followers." The number of L. corticis within a Sitka spruce terminal was highly correlated with the number of weak and dying P. strobi larvae, but not with healthy larvae.L. corticis larvae experimentally deprived of dead P. strobi larvae, behaved as an effective predator, consuming both weak P. strobi larvae and healthy pupae, but apparently not healthy larvae. The transition of L. corticis from second to third instar appeared to occur only after sufficient weevils had been consumed. When an excess of prey was present, L. corticis larvae consumed a mean of 2.9 P. strobi pupae over their entire life cycle. In choice experiments, L. corticis larvae searched for and located mining P. strobi larvae, and fed preferentially on P. strobi pupae rather than granary weevil pupae, Sitophilus granarius L. Under certain circumstances, L. corticis could be an important regulatory agent of P. strobi populations.


1994 ◽  
Vol 24 (4) ◽  
pp. 810-816 ◽  
Author(s):  
E.S. Tomlin ◽  
J.H. Borden

Sitka spruce, Piceasitchensis (Bong.) Carr., from 27 provenances and five sites in British Columbia, were examined for traits of leader morphology that might be involved in resistance to the white pine weevil, Pissodesstrobi (Peck). Trees from the Usk Ferry provenance at Head Bay and the Kitwanga provenance at Nass River both had low incidence of weevilling, and had needles pressed more closely against the stems by up to 20° than trees from other provenances. At Fair Harbour, trees from the two most resistant provenances, Haney and Cedarvale, had inner resin ducts that were approximately twice the diameter of those in trees from the most susceptible provenances. Resistant trees from these two provenances also had significantly more outer resin ducts than those from any other provenance planted at any of the five sites. Values ranged from 28 outer ducts per centimetre for Haney trees, to <1 per centimetre for very susceptible trees from the Masset Sound provenance in the Queen Charlotte Islands, where the absence of weevils could have eliminated any selection for trees with a high density of resin ducts. We hypothesize that trees from the Haney and Cedarvale provenances may have large numbers of outer resin ducts as an important resistance mechanism, which could be used as a selection criterion for resistance. Resistant trees from other provenances such as Big Qualicum, Kitwanga, and Green Timbers, which have fewer outer resin ducts than those from Haney and Cedarvale, must rely heavily on mechanisms other than those associated with the resin system morphology.


1993 ◽  
Vol 69 (5) ◽  
pp. 600-603 ◽  
Author(s):  
R. G. Fraser ◽  
D. G. Heppner

Young Sitka spruce, Picea sitchensis (Bong.) Carr., trees in three stands were treated with either Gelcaps® containing oxydemeton-methyl or Acecaps® containing acephate to test their effectiveness in protecting trees from white pine weevil, Pissodes strobi (Peck) attack. All treatments were applied in late March 1989. Weevil attack was recorded in early September 1989, 1990 and 1991. Attack was significantly reduced (P < 0.01) in all but one stand/treatment combination in 1989. Gelcaps provided significant protection (P < 0.01) in two of three stands after two years. Stem implants containing systemic insecticide can protect young Sitka spruce from weevil attack. Alternative delivery systems, such as the Ezect® lance, should be evaluated as they may improve the speed and lower the cost of operational treatments. Keywords: acephate, oxydemeton-methyl, stem implants, systemic insecticides, white pine weevil


1984 ◽  
Vol 116 (1) ◽  
pp. 41-44 ◽  
Author(s):  
R. I. Alfaro ◽  
J. H. Borden ◽  
L. J. Harris ◽  
W. W. Nijholt ◽  
L. H. McMullen

AbstractPine oil effectively reduced feeding by the white pine weevil, Pissodes strobi Peck, in a laboratory feeding bioassay utilizing agar discs containing dry, powdered bark of its host Sitka spruce, Picea sitchensis (Bong.) Carr. Possible utilization of pine oil under field conditions is discussed.


2011 ◽  
Vol 65 (6) ◽  
pp. 936-948 ◽  
Author(s):  
Dawn E. Hall ◽  
Jeanne A. Robert ◽  
Christopher I. Keeling ◽  
Dominik Domanski ◽  
Alfonso Lara Quesada ◽  
...  

Botany ◽  
2010 ◽  
Vol 88 (10) ◽  
pp. 937-937 ◽  
Author(s):  
Jeanne A. Robert ◽  
Lufiani L. Madilao ◽  
Rick White ◽  
Alvin Yanchuk ◽  
John King ◽  
...  

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