Abstract
The cottonwood leaf beetle, Chrysomela scripta F., is a serious defoliator of plantation Populus in the United States. Current control methods include biorational and synthetic chemicals as well as selecting Populus clones resistant or tolerant to C. scripta defoliation. Specific ratios of long-chain fatty alcohols to alpha-tocopherylquinone (α-TQ) on the leaf surface of Populus spp. act as phagostimulants to adult C. scripta. The chemical concentrations and ratios vary among Populus clones; however, the effect of defoliation on the subsequent production of these chemicals is unknown. We investigated the effects of defoliation, clone, and season on Populus leaf surface chemical production. Chemical concentrations and ratios were monitored in 1998 and 1999 on eight Populus clones with and without larval C. scripta defoliation. Chemicals were extracted from the leaf surface and analyzed via gas chromatography. Larval C. scripta defoliation rarely caused changes in leaf surface chemistry at the defoliation levels tested; however, the production of these phagostimulants did vary by clone and season. Foliar alcohol and α-TQ concentrations and α-TQ:total alcohol ratios differed significantly among clones. Furthermore, α-TQ concentrations and α-TQ:total alcohol ratios varied temporally in some, but not all, clones. In general, foliar alcohol and α-TQ concentrations either did not vary or increased, but α-TQ:total alcohol ratios declined throughout the growing season. This research illustrates that the production of leaf surface phagostimulants is not a function of defoliation, but is most likely controlled by genetic and physiologic processes. Additionally, because Populus clones vary in their foliar chemistry, this variation could be exploited in tree breeding programs.
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Claims 10
Claim · model-written summary
Larval defoliation rarely altered leaf surface chemistry at the tested levels.
- Treatment
- Larval C. scripta defoliatione0
- Interactor
- C. scripta
Chrysomela scriptae0pest - Outcome
- leaf surface chemistrye0
- Direction
- rarely caused changese0
- Qualifier
- at the defoliation levels testede0
PopulusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Larval C. scripta defoliation rarely caused changes in leaf surface chemistry at the defoliation levels tested”
t0“Populus”
Claim · model-written summary
Foliar alcohol concentration differed significantly among clones.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar alcohol and α-TQ concentrations and α-TQ:total alcohol ratios differed significantly among clones”
t0“Populus”
Claim · model-written summary
α-TQ concentration differed significantly among clones.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar alcohol and α-TQ concentrations and α-TQ:total alcohol ratios differed significantly among clones”
t0“Populus”
Claim · model-written summary
α-TQ to total alcohol ratios differed significantly among clones.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar alcohol and α-TQ concentrations and α-TQ:total alcohol ratios differed significantly among clones”
t0“Populus”
Claim · model-written summary
α-TQ concentrations varied over time in some clones.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“α-TQ concentrations and α-TQ:total alcohol ratios varied temporally in some, but not all, clones”
t0“Populus”
Claim · model-written summary
α-TQ to total alcohol ratios varied over time in some clones.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“α-TQ concentrations and α-TQ:total alcohol ratios varied temporally in some, but not all, clones”
t0“Populus”
Claim · model-written summary
Foliar alcohol concentrations generally stayed constant or increased during the growing season.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“foliar alcohol and α-TQ concentrations either did not vary or increased”
t0“Populus”
Claim · model-written summary
α-TQ concentrations generally stayed constant or increased during the growing season.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“foliar alcohol and α-TQ concentrations either did not vary or increased”
t0“Populus”
Claim · model-written summary
α-TQ to total alcohol ratios declined during the growing season.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“α-TQ:total alcohol ratios declined throughout the growing season”
t0“Populus”
Claim · model-written summary
Clone variation in foliar chemistry could be used in tree breeding.
- Outcome
- this variation could be exploited in tree breeding programse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“because Populus clones vary in their foliar chemistry, this variation could be exploited in tree breeding programs”