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A cabbage root fly oviposition deterrent in the frass of garden pebble moth caterpillars

Jones, T.H., Cole, R.A., Finch, S.
Entomologia experimentalis et applicata 1988 v.49 no.3 pp. 277-282
Brassicaceae, Delia radicum, Evergestis, Mamestra brassicae, Plutella xylostella, aqueous solutions, buffers, cauliflower, chemical analysis, field experimentation, frass, gardens, insect larvae, leaves, moths, oviposition, polyamides, sinapic acid, spraying
The cabbage root fly, Delia radicum (L.), was deterred from laying eggs on cauliflower plants sprayed with a water-soluble extract of the frass of caterpillars of the garden pebble moth, Evergestis forficalis (L.), which had fed on a range of cruciferous species. Chemical analysis of the extract revealed the presence of a phenolic acid which was not present in the frass of larvae of two other Lepidoptera (Mamestra brassicae (L.) and Plutella xylostella (L.)) that had fed on the same range of cruciferous plants. The deterrent chemical was isolated and identified as sinapic (3,5-dimethoxy-4-hydroxycinnamic) acid. Spraying cauliflower plants with a buffered solution of the acid in water (0.1, 1 and 10 mM) reduced the numbers of cabbage root fly eggs laid by 60-70%. In field experiments, the deterrent effect persisted 5 days after leaves were sprayed with a buffered, aqueous solution of the acid (10 mM).