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CC BY-NC-ND V4.0, Open Access
Dissertation
Examination of the resistance in the wild beach strawberry, Fragaria chiloensis (L.) to the strawberry aphid, Chaetosiphon fragaefolii (Cockerell)
Washington State University
Doctor of Philosophy (PhD), Washington State University
12/1985
DOI:
https://doi.org/10.7273/000007346
Abstract
The resistance found in certain clones of the wild beach strawberry, Fragaria chiloensis (L.) to the strawberry aphid, Chaetosiphon fragaefolii (Cockerell), was evaluated in field and laboratory studies. The relative resistance of the clones were evaluated by sampling the aphid population on field-grown plants and by measuring aphid survival on the strawberries in a growth room. Aphids survived equally well on susceptible 'Alpine' strawberries, F. vesca L., after being on resistant strawberries or starved for 24 h. Aphids left resistant strawberries within 24-48 h in choice and no-choice tests.
No differences in initial probing behavior were observed during the first 24 h after aphids were placed on susceptible or resistant strawberries. Aphids spent less time probing leaves of resistant strawberries than those of a susceptible strawberry clone during the next 24 h.
Strawberry aphid feeding on two strawberry clones was electronically recorded for a 23-h period. Aphids spent more time ingesting on F. X ananassa Duchesne 'Totem' than on F. chiloensis 'Del Norte'.
Aphids lost significantly more weight and produced significantly less honeydew on intact leaves of 'Del Norte' than on 'Totem'. Aphid survival and honeydew production increased on 'Del Norte' leaves with detachment and again after leaves had been detached one week. Aphid survival and honeydew production on 'Totem' leaves were similar whether intact, newly detached or detached for one week.
Aphid stylets or sheaths were always observed in the phloem tissue of 'Totem' but were found in the phloem of 'Del Norte' only 57% of the time. The sucrose levels in phloem exudates of 'Totem' and 'Del Norte' ranged between 20-30%. Sucrose was the only sugar found in phloem exudates using thin layer chromatography.
Strawberry aphid resistance is probably due to the presence of feeding deterrents or the absence of phagostimulants. Aphids do not feed continuously on resistant strawberries and starve to death.
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Details
- Title
- Examination of the resistance in the wild beach strawberry, Fragaria chiloensis (L.) to the strawberry aphid, Chaetosiphon fragaefolii (Cockerell)
- Creators
- Patricia Anne McKay
- Contributors
- Carl H. Shanks Jr. (Chair)Thomas M. Sjulin (Committee Member)Stephen D WYATT (Committee Member)Vincent R Franceschi (Committee Member)Gary L. Piper (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Entomology
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 80
- Identifiers
- 99901225654301842
- Language
- English
- Resource Type
- Dissertation