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" Distribution, abundance, and control of the southern buffalo gnat, Cnephia pecuarum (Diptera: "
D. W. Atwood
M. V. Meisch
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Latin Dissertation
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English
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| Record Number
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1112917
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| Doc. No
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TLpq304237919
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| Main Entry
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D. W. Atwood
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M. V. Meisch
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| Title & Author
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Distribution, abundance, and control of the southern buffalo gnat, Cnephia pecuarum (Diptera:\ D. W. AtwoodM. V. Meisch
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| College
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University of Arkansas
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| Date
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1996
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| student score
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1996
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| Degree
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Ph.D.
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| Page No
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127
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| Abstract
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Studies were conducted to determine the distribution and abundance of the southern buffalo gnat, Cnephia pecuarum, in Arkansas. Field collections determined adult occurrence in 24 counties in southern and eastern Arkansas. Greatest adult density was 7,160 gnats/24 hr. Seasonal occurrence extended from December to April but varied by location and year. Carbon dioxide and 1-octen-3-ol were evaluated individually and in combination as black fly attractants using tent traps. Significantly greater numbers (P usd\lequsd 0.05) of C. pecuarum were collected with CO2 and CO2 + octenol. Conversely, significantly more Simulium meridionale, turkey gnat, were collected with CO2 alone. Overall, octenol alone was not an effective black fly attractant. Susceptibility of southern buffalo gnat larvae to Bacillus thuringiensis var. israelensis (B.t.i.) was examined using a mini-gutter system. Vectobac 12AS was applied at a 4.5 ppm concentration and 10 minute larval exposure period. Water temperature was positively correlated (r = 0.79) to larval mortality. Larval mortality significantly decreased (P usd\lequsd 0.05) as water temperature decreased below 9C, indicating seasonal limits on effectiveness. Vectobac 12AS and Vectobac 24AS provided effective larval control (>75%) in river trials. Effective downstream carry exceeded 2820 m at flow rates of 1.7-20.78 cms. Full river application resulted in larval reduction of 62-95%. Larval mortality varied among and within sampling sites as a function of stream parameters and between larval instars. Telephone surveys were conducted to estimate the economic impact of the southern buffalo gnat. Potential economic loss during severe outbreaks was estimated at usd5,000,000, suggesting a financial return of \usd555 to usd833 for every \usd1 spent on larval control. Field observations obtained during the course of these studies are presented as pertaining to the biology and behavior of C. pecuarum. In addition, river factors are discussed as they relate to egg hatch, larval development and resurgence of C. pecuarum as a pest. Final discussion is aimed at identifying strategies necessary for development of an effective but economical control program for the southern buffalo gnat in Arkansas and Texas based on the findings of this research.
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Bacillus thuringiensis var. israelensis
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Biological sciences
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carbon dioxide
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Entomology
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octenol
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Simulium meridionale
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