The European hazelnut, Corylus avellana L., was imported into the U.S. in the
late 1800's and is now grown throughout the Willamette Valley in Oregon. A native
species of hazelnut, C. cornuta Marshall, is a common shrub found in forested areas of
the Pacific Northwest. Foliage of both C. avellana and C. cornuta was sampled using
beating sheets. The objectives of the study were as follows: 1. To compile a complete list
of the Coleoptera and Heteroptera fauna of both species of hazelnut. 2. To determine the
amount of overlap across host plants. 3. To measure arthropod abundance and species
diversity within functional groups across a forest-edge-orchard gradient. 4. To use
ordination techniques to determine where peak abundance of individual taxa occur along
the forest-edge-orchard gradient. One hundred and thirty-two species of Coleoptera and
forty-nine species of Heteroptera were identified on Hazelnut foliage. The most
abundant Heteroptera in the orchards studied is a newly introduced mirid predator,
Malacocoris chlorizans (Panzer). There is a great deal of overlap between the two
hazelnut species. Most differences are attributed to rare species. Diversity and
abundance of predaceous Coleoptera and Heteroptera were severely hindered by IPM
management practices, involving insecticide usage, within the orchards. However, the
organic orchards retained high levels of diversity and abundance of predaceous
Coleoptera and Heteroptera in the centers of the orchards. The organic orchards had
higher diversity of phytophagous Coleoptera and Heteroptera as compared to IPM
orchards, but the abundance of those insects was not different between the IPM and
organic orchards. The ordinations of the Coloeptera data show that the peak abundances
of individual species often shift along the forest-edge-orchard gradient over time and that
the organic orchards retain peak abundances of predaceous Coleoptera even in late
season. The ordinations of the Heteroptera data show that several mirid predators are at
their peak abundances within the orchards of both IPM and organic orchards. / Graduation date: 2000
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33209 |
| Date | 26 January 2000 |
| Creators | Wetherill, Karen R. |
| Contributors | AliNiazee, Mohammed T. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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