Articles
LINEAR FURANOCOUMARINS AND APIUM PROSTRATUM/SPODOPTERA EXIGUA INTERACTIONS
Article number
381_80
Pages
589 – 595
Language
Abstract
The wild Apium prostratum was shown to be highly resistant to Spodoptera exigua (Hübner) larval feeding (Diawara et al., 1992). The plant also had higher concentrations of the linear furanocoumarins psoralen, bergapten, and xanthotoxin than the susceptible commercial celery ‘Tall Utah 52–70R’ (A. graveolens), suggesting that the resistance could be due to these chemicals.
Additional research, however, indicated possible involvement of other resistance factors.
A study was therefore initiated to determine the toxicity of these linear furanocoumarins to S. exigua under UV radiation (Diawara et al., 1994). Increased dietary concentrations of each individual furanocoumarin significantly decreased insect larval weight, extended generation time, and induced higher mortality.
Combining psoralen with bergapten, xanthotoxin or both resulted in significantly antagonistic effects on insect mortality.
The combination of bergapten and xanthotoxin, however, produced additive effects.
Neither furanocoumarine alone nor in combination with one or two others induced the larval mortality levels caused by the plant.
Breeding efforts were, therefore, undertaken in an attempt to safely transfer the resistance mechanism in the commercial celery by crossing A. prostratum with A. graveolens. The F1 hybrids, with less than one fourth of the levels of furanocoumarins found in their parent A. prostratum, were shown to be still highly resistant to S. exigua. Studies are underway to evaluate the backcrosses to the commercial celery and to determine the chemical basis for the resistance in the wild A. prostratum.
Additional research, however, indicated possible involvement of other resistance factors.
A study was therefore initiated to determine the toxicity of these linear furanocoumarins to S. exigua under UV radiation (Diawara et al., 1994). Increased dietary concentrations of each individual furanocoumarin significantly decreased insect larval weight, extended generation time, and induced higher mortality.
Combining psoralen with bergapten, xanthotoxin or both resulted in significantly antagonistic effects on insect mortality.
The combination of bergapten and xanthotoxin, however, produced additive effects.
Neither furanocoumarine alone nor in combination with one or two others induced the larval mortality levels caused by the plant.
Breeding efforts were, therefore, undertaken in an attempt to safely transfer the resistance mechanism in the commercial celery by crossing A. prostratum with A. graveolens. The F1 hybrids, with less than one fourth of the levels of furanocoumarins found in their parent A. prostratum, were shown to be still highly resistant to S. exigua. Studies are underway to evaluate the backcrosses to the commercial celery and to determine the chemical basis for the resistance in the wild A. prostratum.
Authors
M.M. Diawara, J.T. Trumble, C.F. Quiros
Keywords
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