The species complex and population dynamics of spiders were studied in an abandoned and several commercial apple orchards in Virginia. There were 68 and 45 species found in the abandoned and combined commercial orchards respectively. Species numbers in individual commercial orchards ranged from 18-28. There were 16 species common to all sprayed orchards. Members of the Salticidae, Philodromidae, Thomisidae, Theridiidae, Anyphaenidae, and Dictynidae, together comprised about 90% of the total spiders collected in the abandoned orchard during a one year study. Results from commercial orchards reflected similar findings. Two peaks of spider abundance were usually observed in all orchards; a small one in the spring and a larger one in the late summer-fall. Spiders often represented over 50% of the total predators collected in commercial orchards during the spring and fall. Studies of the association of spiders and various pest-prey indicate that spiders may be important suppressive or regulatory agents especially with regards to aphid and tortricid leafroller populations.
Results of an evaluation of the seasonal efficiency of the limb beating sampling technique indicated that the sampling method was acceptable for quantitative spider population estimates. The time of sampling did not effect the population estimates of spiders during the normal sampling periods of 6 a.m. - 6 p.m.
Spider feeding tests on insect pests-prey and beneficials showed that one pest species could be preyed upon by a complex of spider species. Beneficial insects such as Lepthothrips mali (Fitch) also were susceptible to capture by several spider species. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/45329 |
| Date | 30 October 2008 |
| Creators | McCaffrey, Joseph P. |
| Contributors | Entomology |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis, Text |
| Format | x, 108 leaves, BTD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 39908577, LD5655.V855_1978.M245.pdf |
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