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CC BY-NC-ND V4.0, Open Access
Dissertation
The influence of temperature and natural enemies on population development of woolly apple aphid, Eriosoma lanigerum (Hausmann)
Washington State University
Doctor of Philosophy (PhD), Washington State University
05/1985
DOI:
https://doi.org/10.7273/000007348
Abstract
The developmental rate of woolly apple aphid, Eriosoma lanigerum (Hausmann), reared at constant temperatures was a non-linear function of temperature with a moderate decline at temperatures above the optimum of 26°C. The reproductive rate peaked at 24°C and at this and lower temperatures reproduction continued beyond the end of the third developmental unit after maturation. The maximum total fecundity of 131 progeny per adult occurred at 16°C. The developmental rates of immature stages of the host-specific endoparasitoid, Aphelinus mali Haldeman, were also described by non-linear functions of temperature with peak rates occurring at higher temperatures than for its host. At temperatures above the optimum, alternating high and intermediate temperatures resulted in substantially increased developmental rates for both species compared to rates predicted by constant temperature results. Developmental rates of the parasitoid exceeded those of its host at 3O°C constant and at 32°C with an alternating temperature program. At temperatures below 30°C parasitoid developmental rate decreases more rapidly than that of its host.
Exclusion techniques (caging and insecticidal) were used to investigate the effectiveness of A. mali relative to general aphid predators in the control of woolly apple aphid on young apple trees in central Washington. When predators were excluded A. mali did not prevent aphid populations from reaching unacceptably high levels. Low negative slope values for aphid population growth and percent parasitism in mid- and late summer suggested the parasitoid did not greatly influence aphid population growth. Predators were the dominant factor reducing aphid densities. These included Coccinella transversoguttata Fald. in mid-summer, Chrysopa nigricornis Barm. and Deraeocoris brevis Uhler throughout mid- and late summer. Other factors greatly influencing aphid population densities were high overwintering mortality, high summer temperatures which increased aphid wandering and the production of alate aphids during September.
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Details
- Title
- The influence of temperature and natural enemies on population development of woolly apple aphid, Eriosoma lanigerum (Hausmann)
- Creators
- James Thomas Sinclair Walker
- Contributors
- Stanley C. Hoyt (Chair)Jay F Brunner (Committee Member) - Washington State University, Department of EntomologyGarrell E. Long (Committee Member)Linda R. Moore (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
- 100
- Identifiers
- 99901225654201842
- Language
- English
- Resource Type
- Dissertation