Term of Award

Spring 1998

Degree Name

Master of Science in Biology

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Committee Chair

Daniel V. Hagan

Committee Member 1

Frank E. French

Committee Member 2

Donald J. Drapalik

Abstract

Pine shoots infested with Nantucket pine tip moths (NPTM), Rhyacionia frustrana, were collected from four loblolly pine plots of various ages (1-2 years) and silvicultural treatments (normal and intensive), from June 1997 through January 1998. A total of 5,906 NPTM larvae and/or pupae were collected with 4,309 from normal treated plots and 1,597 from intensive treated plots. Significantly more NPTM larvae and/or pupae were collected from normal treated plots than intensive treated plots. Pine stands were also divided into three sections, road edge, interior and hardwood edge, and infested shoots were collected from each location. Significant differences were found between NPTM abundances in pines along the road edges in normal treated versus intensive treated plots and between pines in the interior of normal treated versus intensive treated plots; however, no significant differences were observed between pines adjacent to the hardwood edges of normal treated and intensive treated plots.

Parasitoids of NPTMs were surveyed, and a total of 11 parasitoid species from two orders, Diptera and Hymenoptera, were collected. The dipteran, Lixophaga mediocris, was the most abundant parasitoid. The eulophid, Hyssopus rhyacioniae, was the second most abundant parasitoid followed by the braconid, Macrocentrus ancylivorus. The other parasitoids included, one bethylid of unidentified genus; one braconid, Bracon variabilis; two chalcidids, Conura side and Haltichella rhyacioniae two eulophids, Horismenus sp. and Sympiesis stigmutipennis; a eupelmid, Eupelmus cyaniceps; a eurytomid, Eurytoma pini, and one ichneumonid, Itoplectis conquisitor.

In addition to the larval and pupal parasitoids of the NPTM, an egg parasite, Trichogramma sp. was also found in the study. Parasitism varied seasonally, 25% of NPTM eggs were found to be parasitized by Trichogramma sp. in March 1997, and none of the NPTM eggs were parasitized in June - August 1997.

A survey (July 1996 - March 1997) of insect associates was made using sweep nets in five loblolly pine plots of various ages and silvicultural treatments. Sweep collections yielded a total of 13 orders and 122 families of insects. The non-parametric Sorenson's Quotient of Similiarity indicated that families collected were similar in all five plots.

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