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Full-Text Articles in Life Sciences
Insecticide Toxicity, Synergism, And Resistance In The German Cockroach (Dictyoptera: Blattellidae), Jeffrey G. Scott, Donald C. Cochran, Blair Siegfried
Insecticide Toxicity, Synergism, And Resistance In The German Cockroach (Dictyoptera: Blattellidae), Jeffrey G. Scott, Donald C. Cochran, Blair Siegfried
Department of Entomology: Faculty Publications
The toxicity of, synergism of, and resistance to insecticides in four strains of German cockroach, Blattella germanica (L.), were investigated. Toxicity of nine insecticides by topical application to the susceptible strain varied >2,000-fold, with deltamethrin (LD50 = 0.004 μg per cockroach) and malathion (LD50 = 8.4 μg per cockroach) being the most and least toxic, respectively. Resistance to pyrethrins (9.5-fold) in the Kenly strain was unaffected by the synergists piperonyl butoxide (PBO) or S,S,S-tributylphosphorotrithioate( DEE), suggesting that metabolism is not involved in this case. Malathion resistance in the Rutgers strain was suppressible with PBO, implicating oxidative metabolism as …
Feeding Behavior Of Nephotettix Virescens (Homoptera: Cicadellidae) On Rice Varieties With Different Levels Of Resistance, H. R. Rapusas, E. A. Heinrichs
Feeding Behavior Of Nephotettix Virescens (Homoptera: Cicadellidae) On Rice Varieties With Different Levels Of Resistance, H. R. Rapusas, E. A. Heinrichs
Department of Entomology: Faculty Publications
The feeding behavior of Nephotettix virescens (Distant) on rice varieties with different levels of resistance was studied using an AC electronic monitor for insect feeding (EMIF) system. Varieties used were TN1 (susceptible), IR36 (moderately resistant), and ASD7, IR60, and IR64 (resistant). Six typical waveforms were recorded, and each type corresponded to a certain activity of the insect during the feeding process as indicated by histological sections of the leaf observed. Significantly more phloem feeding was observed on the susceptible plants than on the moderately resistant and resistant plants. Fifty percent of the total test period was spent feeding on the …
Response To Selection For Virulence Of Nephotettix Virescens (Homoptera: Cicadellidae) On Resistant Rice Cultivars, E. A. Heinrichs, H. R. Rapusas
Response To Selection For Virulence Of Nephotettix Virescens (Homoptera: Cicadellidae) On Resistant Rice Cultivars, E. A. Heinrichs, H. R. Rapusas
Department of Entomology: Faculty Publications
Rate of response to selection for Nephotettix virescens (Distant) virulence was studied for 20 generations on five rice cultivars with different levels of resistance. Rate of response to selection on all cultivars varied depending on the measurement criteria. Survival, growth, progeny production, and weight increased, and developmental period decreased, with selection time. Based on survival, the N. virescens population became highly virulent within one to four generations, whereas high virulence as measured by progeny production generally required more generations of selection. Virulence as measured by the ability to vector tungro virus also increased with selection time.
Modification Of The Effect Of Bacillus Thuringiensis On Sunflower Moth (Lepidoptera: Pyralidae) By Dietary Phenols, Gary J. Brewer, Marc D. Anderson
Modification Of The Effect Of Bacillus Thuringiensis On Sunflower Moth (Lepidoptera: Pyralidae) By Dietary Phenols, Gary J. Brewer, Marc D. Anderson
Department of Entomology: Faculty Publications
The sunflower moth, Homoeosoma electellum (Hulst), a major pest of sunflower (Helianthus annuus L.), is susceptible to Bacillus thuringiensis Berliner, but field control has been inconsistent. Our study was done to determine whether phenolics in damaged sunflower tissue are in a conjugated or free form and whether they influence the toxicity of B. thuringiensis to the sunflower moth. Larvae fed diets containing B. thuringiensis had reduced survival and growth. The LD50 of B. thuringiensis was 52 international units of potency per gram of diet. Phenolic acids are general biocides. They were found in sunflower hybrids largely in the free …
Environmental Influences On Soil Macroarthropod Behavior In Agricultural Systems, Michael G. Villani, Robert J. Wright
Environmental Influences On Soil Macroarthropod Behavior In Agricultural Systems, Michael G. Villani, Robert J. Wright
Department of Entomology: Faculty Publications
Many basic and applied studies in insect ecology have focused on the proximate and ultimate responses of insect populations to their physical and chemical environment (2, 15, 21, 27, 32, 74, 82, 111, 112). From an economic perspective, macro- and microclimatic factors can influence the stress that insect populations inflict on plants and the efficacy of management tactics. For above-ground insects, the mechanisms of behavioral response to environmental factors are often observable, if not always apparent to the researcher. However, this is not typically the situation with soil insects. As a result, field studies of soil insects often quantify only …