Date of Award:

5-1970

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Entomology

Committee Chair(s)

Donald W. Davis

Committee

Donald W. Davis

Committee

W. A. Brindley

Committee

R. M. Lanner

Abstract

Six species of insects were found attacking limber pine cones from July 26, 1968, through October 4, 1969, in Cache National Forest. The three species considered of major importance are: Conophthorus flexilis Hopkins, Dioryctria abietella (D. & S.), and D. sp. near or disclusa Heinrich. The three minor species encountered are; Bradysia sp., Trogoderma parabile Beal, and Asynapta keeni (Foote). In addition to the major and minor cone pests three parasites, Apanteles sp. prob. starki Mason, Elacherus sp., and Hypopteromalus percussor Girault were found associated with the cone pests.

C. flexilis, which completely destroys the cone, was ranked as the number one pest on the basis of numbers present plus severity of damage. During 1968 and 1969 C.flexilis destroyed 11.47 percent of the 1500 cones examined, with a mean of 5.87 larvae per infested cone. The cone moths, D. abietella and D. sp. near or disclusa, were ranked second and third in importance respectively. D. sp. near or disclusa was potentially the more important cone moth, as it caused a total destruction of the seed bearing portion of the cones. However, D. abietella infested 15.40 percent of the cones, in contrast to 2.00 percent by D. sp. near or disclusa.

There were no significant statistical differences in insect populations between 1968 and 1969, although the percent infestation of C. flexilis and D. sp. near or disclusa increased slightly and D. abietella decreased.

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