Document Type

Thesis - Open Access

Award Date

1987

Degree Name

Master of Science (MS)

Department

Entomology

First Advisor

Dr. Emmet R. Easton

Abstract

The stable fly is usually the only biting, blood-sucking fly breeding in appreciable numbers in and around confined animal facilities. An average number of 50 flies per animal can reduce the weight gains of calves on a growing ration by 0.9 kilogram per day. At present, the level of 5 stable flies per front leg of confined beef cattle is used as an indicator of the economic threshold when control measures must be instituted. Since the immature stages of the stable fly develop in decaying organic matter, the most practical control measure has been sanitation or the proper storage and management of grains, silage, haylage, and manure which can support breeding in the feedlot. Campbell and McNeal in Nebraska found chemical control to be of value when residual sprays I were applied to fly resting areas such as the feed bunks, farm buildings, or vegetation surrounding the feedlots. The sterile-insect technique as a method of controlling or eradicating harmful insects gained popularity after the successful eradication of the primary screw-worm fly in the United States by the U.S. Department of Agriculture. It involved the mass-production of the fly, sterilization by gamma radiation, and release of the sterilized flies over infested areas. This resulted in total elimination of the screwworm fly over large geographical areas. Several workers subsequently employed the sterile-insect technique against other insect pests such as the melon fly and the stable fly. Compared to chemical control, the sterile-insect technique is highly selective and does not cause insect resistance. Sterilization is also the only proven pest control method that can actually eradicate an insect species over large areas. The main requirements for the technique to work according to Knipling are: (I) The availability of a method for producing sterility without serious adverse effects on the mating behavior and competitiveness of the insect, (2) A practical method for rearing the insects in large numbers, and (3) Quantitative information on the natural population density. Williams et al., demonstrated that the stable fly can be easily mass-produced and sterilized by 2 kR gamma radiation without affecting its competitiveness and longevity in the field. Previous studies in Florida and on St. Croix, U.S. Virgin Islands indicated that the sterile-insect technique shows promise against the stable fly. This research was initiated to investigate the feasibility of controlling a stable fly population in a beef cattle feedlot in Brookings, South Dakota using the sterile-insect technique. The objectives of the studies were: (1) To determine the population dynamics of the stable fly in the feedlot during the summer season of 1986, (2) To design a practical method of mass-producing the flies in the laboratory, (3) To determine whether actual releases of sterilized flies will have an effect on the reproductive potential of the wild population in the feedlot, and (4) To evaluate a chemosterilant, bisazir, as a possible substitute for gamma radiation in producing sterility in flies to be released in the field. All experiments in this study were carried out at the SDSU Cattle and Sheep Nutrition Research feedlot and at the Physiology Laboratories on SDSU campus from May, 1986 to July, 1987.

Library of Congress Subject Headings

Flies -- Control

Stable fly -- Control

South Dakota State University Theses

Format

application/pdf

Number of Pages

88

Publisher

South Dakota State University

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