Date of Award:

1976

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Advisor/Chair:

Austin B. Haws

Abstract

This study compares insect and cattle consumption of crested wheatgrass (Agropycon spp.) on a site in Sterling Ranch, Utah County, Utah. The hypothesis tested is that insect consumption in general, and specifically consumption by Labops hesperius Uhler, significantly reduces total available cattle forage.

Labops and grasshoppers were probably the major cause of secondary damage at the study site, while the impact of thrips is unknown. A detrimental impact on range was suggested by the data, as insects consumed forage equivalent to 2.8 animal units per month, while cattle consumed forage equivalent to 2.1 animal units per month at the study site. Based on a grazing fee of $1.60 per animal unit per month, this represents a loss of $3.50 per acre. Although a low level Labops population was present at the time of the study, potential exists for this population to reach higher level s that would cause much higher levels of damage.

Crested wheatgrass, the major vegetation at the study site, is capable of resuming growth in the fall if there is sufficient moisture. Because there is only one generation of Labops per year, fall herbage production would not suffer Labops damage, but may suffer damage by other insects that are present in the fall.

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Biology Commons

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