Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 4 of 4

Full-Text Articles in Entire DC Network

Development Of Diagnostic Tools For Detecting Expression Of Resistance-Associated Esterases In The Tobacco Budworm, Heliothis Virescens (F.), Huazhang Huang Jan 2002

Development Of Diagnostic Tools For Detecting Expression Of Resistance-Associated Esterases In The Tobacco Budworm, Heliothis Virescens (F.), Huazhang Huang

LSU Doctoral Dissertations

Esterase-based metabolic resistance was studied using biochemical and biological assays with organophosphate (OP)- and pyrethroid (PYR)- resistant tobacco budworms, Heliothis virescens. In biochemical assays, results suggest that: (1) esterase activities toward all substrates used were enhanced in both resistant strains compared with the susceptible strain, suggesting that esterases were involved in resistance; (2) esterase profiles differed depending on the strain and substrate used, and these differences were visualized by using native polyacrylamide gel electrophoresis; 3) esterase activities toward some pyrethroid substrates were significantly higher (P ≤ 0.01) in the PYR-R strain than those in the OP-R strain. These results suggest …


Screening And Characterization Of Pathogenic Fungi For Possible Control Of Coptotermes Formosanus, Jianzhong Sun Jan 2002

Screening And Characterization Of Pathogenic Fungi For Possible Control Of Coptotermes Formosanus, Jianzhong Sun

LSU Doctoral Dissertations

Coptotermes formosanus was used as “bait” to isolate pathogenic fungi from soil. Fifteen pathogenic fungal isolates were obtained, all either Metarhizium anisopliae (six isolates) or Beauveria bassiana (nine isolates). There were no differences in numbers of fungal isolates from the three sampling locations. However, significantly more isolates were found in woodlands (eleven) than in pastures (four). Median lethal doses (LD50s) of these fungal species to C. formosanus were interspersed, indicating that fungal isolates rather than species had the greatest effect on virulence. In vitro growth characteristics were significantly correlated with virulence against termites, suggesting that fungal virulence might be predicted …


Evaluation Of Bacillus Thuringiensis Transgenic Field Corn For Management Of Louisiana Corn Pests, Boris A. Castro Jan 2002

Evaluation Of Bacillus Thuringiensis Transgenic Field Corn For Management Of Louisiana Corn Pests, Boris A. Castro

LSU Doctoral Dissertations

Efficacy of Bt corn hybrids expressing an insecticidal delta-endotoxin through different transformation events was evaluated in Louisiana. Efficacy levels were determined for southwestern corn borer (SWCB), Diatraea grandiosella Dyar; sugarcane borer (SCB), Diatraea saccharalis (F.); corn earworm (CEW), Helicoverpa zea (Boddie); and fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith). Insect (neonates and third instars) susceptibility was evaluated on Bt and non-Bt corn plants (V6 and R1 stages) in field plots and plant tissue in laboratory studies. Bt corn hybrids with MON810 and CBH351 transformation events sustained significantly (P < 0.05) less injury caused by SWCB, SCB, and FAW during infestations at mid-whorl stage. SWCB, SCB, and CEW infestations during silking stage were significantly reduced in Bt hybrids with the MON810 event. However, CEW infestations …


Effects Of Fire Frequency And The Red Imported Fire Ant On Native Insects In A Louisiana Longleaf Pine Savanna, Deanna M. Colby Jan 2002

Effects Of Fire Frequency And The Red Imported Fire Ant On Native Insects In A Louisiana Longleaf Pine Savanna, Deanna M. Colby

LSU Doctoral Dissertations

Ants and ground beetles were collected in pitfall traps from a longleaf pine savanna in the early stages of restoration. Insect abundance and species richness were compared among four treatment combinations of two fire frequencies and presence and absence of an exotic ant, Solenopsis invicta, the red imported fire ant. Amdro® was used to suppress S. invicta. Fire treatments consisted of a single fire in a two year period or two fires in a two year period, one applied each year. Fires were applied late in the growing season both years. Ten of the 28 ground beetle species …