Journal of the Kansas Entomological Society (2003) 76, 387-396

P. Foster, M. Noll, S. Grugel and L.D. Charlet (2003)
A reinvestigation of the role of sunflower chemicals in host selection by female banded sunflower moth, Cochylis hospes (Walsingham) (Lepidoptera: Tortricidae)
Journal of the Kansas Entomological Society 76 (3), 387-396
Abstract: The involvement of host plant chemicals in host selection by female banded sunflower moth, Cochylis hospes, was reinvestigated. Pentane, dichloromethane, and methanol extracts of R3 (pre-bloom) Helianthus annuus (sunflower) heads, as well as a pentane extract of sunflower leaves, all elicited oviposition by females. Rotary evaporation of a pentane extract of R3 sunflower heads resulted in decreased, but still significant, activity in the extract, suggesting that both volatile and nonvolatile chemicals are involved in host selection. Behavioral observations supported this, with females landing more frequently, and staying longer, on models treated with extract. The basis of female preference for pre-bloom over post-bloom sunflower heads was investigated. In contrast to a previous report, sunflower pollen had little or no effect on the ovipositional responses of females on a substrate treated with a stimulatory pentane sunflower head extract. Females laid significantly more eggs on isolated involucral bracts from pre-bloom heads than from post-bloom heads. However, dichloromethane extracts of the bracts from the heads of the two growth stages were equally stimulatory to females when tested in a binary choice test. Together these results suggest that temporal changes in bract morphology, may be responsible for the preference of females for pre- over post-bloom heads. Silica fractionation of the pentane and dichloromethane extracts gave 3 and 5 active fractions, respectively. These studies provide the basis for future studies aimed at isolating the chemicals involved in host selection by female C. hospes.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
pheromones/attractants/traps

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cochylis hospes	Sunflower (Helianthus annuus)