Life Sciences Commons^™

Rice Insects: The Role Of Host Plant Resistance In Integrated Management Systems, E. A. Heinrichs

Department of Entomology: Faculty Publications

Insects are among the most important abiotic and biotic constraints to rice production. National rice research programs are in various stages in the development and implementation of integrated pest management (IPM) stratagies for rice insect control. Among the various control tactics, insect resistant cultivars are sought as the major tactic in rice IPM. Through the activities of interdisciplinary teams of scientists significant progress has been made in the development and release of insect resistant cultivars to farmers. Because of its compatibility with other control tactics insect resistance has proven to fit well into the IPM approach to rice insect control …

Biochemical Characterization Of Hydrolytic And Oxidative Enzymes In Insecticide Resistant And Susceptible Strains Of The German Cockroach (Dictyoptera: Blattellidae), Blair Siegfried, Jeffrey G. Scott

Department of Entomology: Faculty Publications

We have identified resistance mechanisms in the German cockroach, Blattella gemanica (L.), for propoxur and chlorpyrifos in strains of cockroaches that display multiresistance to several organophosphate and carbamate insecticides. The resistance mechanisms involve the combined effects of increased oxidative and hydrolytic metabolism and both strains are resistant to chlorpyrifos and propoxur. Experiments designed to test for similarity in metabolic enzymes suggest that, although the mechanisms involve similar processes, the enzymes responsible for insecticide detoxification are different in the two strains. Both resistant strains exhibited enhanced activity toward a-naphtholic esters relative to a standard susceptible strain; however, analysis of the progeny …

Assessing Needs For Computer Pest Management Software In Nebraska Agriculture, Robert J. Wright

Department of Entomology: Faculty Publications

A mail survey was conducted to assess current computer hardware use and perceived needs of potential users for software related to crop pest management in Nebraska. Surveys were sent to University of Nebraska-Lincoln agricultural extension agents, agribusiness personnel (including independent crop consultants), and crop producers identified by extension agents as computer users. There were no differences between the groups in several aspects of computer hardware use (percentage computer use, percentage IBM-compatible computer, amount of RAM memory, percentage with hard drive, hard drive size, or monitor graphics capability). Responses were similar among the three groups in several areas that are important …

Mitochondrial Transfer Rna Genes In A Black Fly, Simulium Vittatum (Diptera: Simuliidae), Indicate Long Divergence From Mosquito (Diptera: Culicidae) And Fruit Fly (Diptera: Drosophilidae), K. P. Pruess, X. Zhu, T. O. Powers

Department of Entomology: Faculty Publications

Sequences are given for nine complete genes and one partial mitochondrial tRNA gene of the black fly, Simulium vittatum (Zetterstedt). Sequenced tRNA genes were for alanine, arginine, asparagine, aspartic acid, glutamic acid, glycine, leucine(CUN), lysine, serine(AGN), and valine. Nucleotides were aligned with the same previously sequenced genes in Aedes albopictus Skuse and Drosophila yakuba Burla. A cluster of six tRNA genes, which differ in arrangement in Ae. albopictus and D. yakuba, was amplified by PCR and found to have the same position and orientation in S. vittatum as in D. yakuba. Overall, similarity with either D. yakuba or …

Sensitivity To 2,4-D In Sunflower As An Indicator Of Tolerance To The Sunflower Midge (Diptera: Cecidomyiidae), Marc D. Anderson, Gary J. Brewer

Department of Entomology: Faculty Publications

Nine sunflower hybrids were evaluated for their sensitivity to 2,4-dichlorophenoxyacetic acid (2,4-D) as measured by the production of ethylene. Sensitivity to 2,4-D was then compared with the degree of field tolerance to the sunflower midge, Contarinia schulzi Gagné, exhibited by each hybrid. For the hybrids evaluated, ethylene production increased with 2,4-D concentration and sensitivity to 2,4-D was inversely proportional to midge tolerance. The procedure may be useful in identifying midge tolerant germplasm.

First Report Of The Chinch Bug (Heteroptera: Lygaeidae) Egg Parasitoid Eumicrosoma Beneficum Gahan (Hymenoptera: Scelionidae) In Nebraska, Robert Wright, Stephen D. Danielson

Department of Entomology: Faculty Publications

A scelionid wasp, Eumicrosoma beneficum Gahan, was reared from chinch bug, Blissus leucopterus leucopterus (Say), eggs collected from wheat (Triticum aestivum L.) near Odell, Nebraska, in June 1989. Three-hundred twenty-one of 680 chinch bug eggs (47.2%) were parasitized by E. beneficum. Based on a subsample of 92 wasps the population was 64.1% female. This is the first report of this wasp from Nebraska.

Comparison Of Chemigated And Aerially-Applied Chlorpyrifos And Fenvalerate For Control Of European Corn Borer (Lepidoptera: Pyralidae) Larvae, Thomas J. Weissling, Frank B. Peairs, Stan D. Pilcher

Department of Entomology: Faculty Publications

Aerial and overhead center-pivot irrigation system (chemigated) applications of chlorpyrifos 4 emulsifiable concentrate (EC) and fenvalerate 2.4EC significantly reduced numbers of first- and second-generation European corn borer, Ostrinia nubilalis Hubner, larvae in field corn, Zea mays L. The number of first-generation O. nubilalis larvae, pupae, or cavities per plant in plots chemigated with chlorpyrifos in 1984 was significantly less than in plots where chlorpyrifos was applied aerially. A similar trend was observed for fenvalerate in 1985. No significant differences among application methods were observed for second-generation O. nubilalis treatments. Chlorpyrifos and fenvalerate were effective O. nubilalis control agents but efficacy …

Field Worker Exposure To Selected Insecticides Applied To Com Via Center-Pivot Irrigation, Shripat T. Kamble, Matthew E. Byers, John F. Witkowski, Clyde L. Ogg, Gerald W. Echtenkamp

Department of Entomology: Faculty Publications

Field workerswere monitored for dermal and respiratory exposure to chlorpyrifos (with and without crop oil), carbaryl, and permethrin at reentry intervals of 2, 4, 8, 24, and 48 h after application. Insecticides were applied to R3 stage corn through an overhead center-pivot irrigation system. Dermal exposure was measured by analyzing 18 gauze pads attached to the clothing of workers to represent human body regions. Hand exposure was determined using cotton gloves. Respiratory exposure was determined using portable air samplers equipped with polyurethane foam plugs to trap ambient insecticide residues. Gas liquid chromatography was used to quantify residues of chlorpyrifos and …

Insect, Mite, And Nematode Pests Of Oat, Jaime E. Araya, John E. Foster

Department of Entomology: Faculty Publications

Various arthropods and nematodes cause damage to oat (Avena sativa L. and A. byzantina K. Koch.) plants throughout their life. No stage is free from damage. Crops can be affected from the seedling stage until the grain is harvested. Pests of oat are either polyphagous (damaging a wide range of plants) or oligophagous (feeding on only a few plant species). Few, if any pests, are truly specific to oat crops.

The presence of various pest species in oat fields does not necessarily imply that yield reduction will result. Hundreds of arthropod species feed on oat cultivated in the USA …

Proposed System Of Nomenclature For Biotypes Of Hessian Fly (Diptera: Cecidomyiidae) In North America, F. L. Patterson, John E. Foster, H. W. Ohm, J. H. Hatchett, P. L. Taylor

Department of Entomology: Faculty Publications

Twenty genes in wheat, Triticum spp., for resistance to Hessian fly, Mayetiola destructor (Say),have been previously designated H1 to H20. The location on wheat chromosomes of some of the genes is known, but several have not yet been assigned to specific chromosomes. Four wheat differential cultivars have been used to identify 16 possible biotypes of Hessian fly; biotypes were designated GP and A-O. If an additional differential host genotype were added, it is apparent that there are not enough letters in the alphabet to designate all of the biotypes. Therefore, a new system of biotype designation is proposed. Three …