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High Plains Wheat Mosaic Virus: An Enigmatic Disease Of Wheat And Corn Causing The High Plains Disease, Satyanarayana Tatineni, Gary Hein

Department of Entomology: Faculty Publications

Brief history: In 1993, severe mosaic and necrosis symptoms were observed on corn (maize) and wheat from several Great Plains states of the USA. Based on the geographical location of infections, the disease was named High Plains disease and the causal agent was tentatively named High Plains virus. Subsequently, researchers renamed this virus as maize red stripe virus and wheat mosaic virus to represent the host and symptom phenotype of the virus. After sequencing the genome of the pathogen, the causal agent of High Plains disease was officially named as High Plains wheat mosaic virus. Hence, High Plains virus, …

Integrated Crop–Livestock Systems In Paddy Fields: New Strategies For Flooded Rice Nutrition, Luiz Gustavo De O. Denardin, Amanda P. Martins, Felipe De C. Carmona, Murilo G. Veloso, Gabriela I. Carmona, Paulo César De F. Carvalho, Ibanor Anghinoni

Department of Entomology: Faculty Publications

Integrated crop–livestock systems (ICLSs) appear as a good alternative to increase nutrient use efficiency (NUE) in rice (Oryza sativa L.) through the improvement in nutrient cycling and soil chemical attributes in paddy fields. The objective of this study was to evaluate the impact of an ICLS on soil chemical attributes and on the fertilization requirement of N, P, and K by flooded rice in the Brazilian subtropical region. Nutritional status, yield, and NUE of flooded rice were evaluated by fertilization trials through rice response to different fertilization rates of N, P, and K. Soil chemical attributes were evaluated at …

Global Responses Of Resistant And Susceptible Sorghum (Sorghum Bicolor) To Sugarcane Aphid (Melanaphis Sacchari), Hannah M. Tetreault, Sajjan Grover, Erin Scully, Tammy Gries, Nathan A. Palmer, Gautam Sarath, Joe Louis, Scott E. Sattler

Department of Entomology: Faculty Publications

The sugarcane aphid (Melanaphis sacchari) has emerged as a significant pest for sorghum. The use of sugarcane aphid-resistant sorghum germplasm with integrated pest management strategies appears to be an excellent solution to this problem. In this study, a resistant line (RTx2783) and a susceptible line (A/BCK60) were used to characterize the differences in plant responses to the sugarcane aphid through a series of experiments, which examined global sorghum gene expression, aphid feeding behavior and inheritance of aphid resistance. The global transcriptomic responses to sugarcane aphids in resistant and susceptible plants were identified using RNA-seq and compared to the …

Resistance In 27 Rice Cultivars To Sugarcane Borer (Lepidoptera: Crambidae), F. Correa, C. L. T. Silva, A. P. Pelosi, A. C. S. Almeida, E. A. Heinrichs, J. A. F. Barrigossi, F. G. Jesus

Department of Entomology: Faculty Publications

Rice (Oryza sativa L.) is considered one of the most important crops in the world, and the sugarcane borer, Diatraea saccharalis Fabricius (Lepidoptera: Crambidae), is among the key pests damaging the crop in the Americas. The objective of this work was to identify rice genotypes as a source of resistance to D. saccharalis. Rice plants were infested in the greenhouse and subsequently evaluated for damage, larval weight and survival, and stem size. The cultivars “Bonança,” “Caripuna,” “IR 42,” “Canela de Ferro,” “SWA Norte,” “BR IRGA 409,” “Pepita,” “Serra Dourada,” “Araguaia,” “Xingú,” “Tangará,” and “Soberana” showed antibiosis, antixenosis, or …

Molecular Gut-Content Analysis Reveals High Frequency Of Helicoverpa Zea (Lepidoptera: Noctuidae) Consumption By Orius Insidiosus (Hemiptera: Anthocoridae) In Sweet Corn, Julie A. Peterson, E. C. Burkness, James D. Harwood, W. D. Hutchison

Department of Entomology: Faculty Publications

Management of corn earworm Helicoverpa zea in sweet corn grown for processing can be challenging due to the lack of effective transgenic and chemical control options. However, biological control by generalist predators can provide a significant impact on pests in this cropping system. One of the most ubiquitous predators of H. zea and other lepidopterans is the insidious flower bug, Orius insidiosus. This small hemipteran has been observed as an important mortality agent of H. zea in several cropping systems, but the strength of the trophic connection between these species has not been documented in sweet corn. Molecular gut-content …

Attack And Defense Movements Involved In The Interaction Of Spodoptera Frugiperda And Helicoverpa Zea (Lepidoptera: Noctuidae), José P. F. Bentivenha, Edson L.L. Baldin, Débora G. Montezano, Thomas E. Hunt, Silvana L. Paula-Moraes

Department of Entomology: Faculty Publications

The fall armyworm, Spodoptera frugiperda (J. E. Smith) and the corn earworm, Helicoverpa zea (Boddie) are among the main pests of maize. Both species exhibit cannibalistic behavior and quite often share the same feeding guild in maize (maize ears), which can result in several interspecific and intraspecific interactions. Paired interaction scenarios of intraspecific and interspecific larvae were assessed in arenas in the presence and absence of food to characterize movements resulting from interactions of these insects. There was a difference in the frequency of behavioral movements in all the interactions, except for S. frugiperda in the presence of food. Head …

Integration Of Plant Defense Traits With Biological Control Of Arthropod Pests: Challenges And Opportunities, Julie A. Peterson, Paul J. Ode, Camila Oliveira-Hofman, James D. Harwood

Department of Entomology: Faculty Publications

Crop plants exhibit a wide diversity of defensive traits and strategies to protect themselves from damage by herbivorous pests and disease. These defensive traits may be naturally occurring or artificially selected through crop breeding, including introduction via genetic engineering. While these traits can have obvious and direct impacts on herbivorous pests, many have profound effects on higher trophic levels, including the natural enemies of herbivores. Multi-trophic effects of host plant resistance have the potential to influence, both positively and negatively, biological control. Plant defense traits can influence both the numerical and functional responses of natural enemies; these interactions can be …

Effect Of Cry1f Maize On The Behavior Of Susceptible And Resistant Spodoptera Frugiperda And Ostrinia Nubilalis, Ana María Vélez, Analiza P. Alves, Erin E. Blankenship, Blair Siegfried

Department of Entomology: Faculty Publications

Understanding the behavior of pests targeted with Bacillus thuringiensis Berliner (Bt) crops is important to define resistance management strategies. Particularly the study of larval movement between plants is important to determine the feasibility of refuge configurations. Exposure to Bt maize, Zea mays L. (Poaceae), has been suggested to increase larval movement in lepidopteran species but few studies have examined the potential for resistance to interact with behavioral responses to Bt toxins. Choice and no-choice experiments were conducted with Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) and Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) to determine whether Cry1F resistance influences neonate movement. Leaf discs …

Evidence Of Field-Evolved Resistance To Bifenthrin In Western Corn Rootworm (Diabrotica Virgifera Virgifera Leconte) Populations In Western Nebraska And Kansas, Adriano E. Pereira, Haichuan Wang, Sarah N. Zukoff, Lance Meinke, B. Wade French, Blair Siegfried

Department of Entomology: Faculty Publications

Pyrethroid insecticides have been used to control larvae or adults of the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, a key pest of field corn in the United States. In response to reports of reduced efficacy of pyrethroids in WCR management programs in southwestern areas of Nebraska and Kansas the present research was designed to establish a baseline of susceptibility to the pyrethroid insecticide, bifenthrin, using susceptible laboratory populations and to compare this baseline with susceptibility of field populations. Concentration-response bioassays were performed to estimate the baseline susceptibility. From the baseline data, a diagnostic concentration (LC99) was determined and …

Planting Date And Variety Selection For Management Of Viruses Transmitted By The Wheat Curl Mite (Acari: Eriophyidae), Anthony J. Mcmechan, Gary Hein

Department of Entomology: Faculty Publications

Wheat is an important food grain worldwide, and it is the primary dryland crop in the western Great Plains. A complex of three viruses (Wheat streak mosaic, Wheat mosaic, and Triticum mosaic viruses) is a common cause of loss in winter wheat production in the Great Plains. All these viruses are transmitted by the wheat curl mite (Aceria tosichella Keifer). Once these viruses are established, there are no curative actions; therefore, prevention is the key to successful management. A study was designed to evaluate preventative management tactics (planting date, resistant varieties) for reducing the impact from this virus complex. …

Taxonomy And Biogeography Of The New Caledonian Species Of Xylopia L. (Annonaceae), David M. Johnson, Jérôme Munzinger, Julie A. Peterson, Nancy A. Murray

Department of Entomology: Faculty Publications

A taxonomic review of the New Caledonian representatives of the pantropical tree genus Xylopia L. (Annonaceae) is presented based on museum study of 157 collections. Distinctions are clarified among the four endemic species, two of them previously undescribed in flower and two others described in the literature from only the type collections. A key and species descriptions are presented. Xylopia pancheri Baill., the most frequently collected species, occurs in maquis environments with ultramafic rocks in the central and southern regions of the island, as well as on the Ile des Pins. Xylopia vieillardii Baill. is widespread in low elevation humid …

Genetic Characterization Of North American Populations Of The Wheat Curl Mite And Dry Bulb Mite, Gary L. Hein, Roy French, Benjawan Siriwetwiwat, James W. Amrine

Department of Entomology: Faculty Publications

The wheat curl mite, Aceria tosichella Keifer, transmits at least three harmful viruses, wheat streak mosaic virus (WSMV), high plains virus (HPV), and Triticum mosaic virus (TriMV) to wheat (Triticum aestivum L.) throughout the Great Plains. This virus complex is considered to be the most serious disease of winter wheat in the western Great Plains. One component of managing this disease has been developing mite resistance in wheat; however, identification of mite biotypes has complicated deployment and stability of resistance. This biotypic variability in mites and differential virus transmission by different mite populations underscores the need to better understand …

Seasonal Population Dynamics Of The Potato Psyllid (Hemiptera: Triozidae) And Its Associated Pathogen “Candidatus Liberibacter Solanacearum” In Potatoes In The Southern Great Plains Of North America, John A. Goolsby, John J. Adamczyk Jr., J. M. Crosslin, Noel N. Troxclair, J. R. Ancisco, Gerhard G. Bester, J. D. Bradshaw, Edsel D. Bynum Jr., L. A. Carpio, Don C. Henne, Ankush Joshi, Joseph E. Munyaneza, Pat Porter, Phillip E. Sloderbeck, J. R. Supak, C. M. Rush, F. J. Willett, B. J. Zechmann, B. A. Zens

Department of Entomology: Faculty Publications

The potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), and its associated pathogen “Candidatus Liberibacter solanacearum” (Ca. L. solanacearum), the putative causal agent of zebra chip (ZC) disease in potatoes (Solanum tuberosum L.), were sampled in commercial potato fields and untreated control plots for 3 yr in multiple locations in Texas, Kansas, Nebraska, and Colorado. Populations of the potato psyllid varied across years and across potato growing regions. However, the percentage of potato psyllids infected with Ca. L. solanacearum although variable across years, was consistently highest in the Lower Rio Grande Valley of Texas (LRGV), the reported overwintering …

High-Throughput Transcriptome Sequencing For Snp And Gene Discovery In A Moth, Nicholas J. Miller, Jing Sun, Thomas W. Sappington

Department of Entomology: Faculty Publications

The western bean cutworm, Striacosta albicosta (Smith) (Leptidoptera: Noctuidae) is a pest of corn (Zea mays L.) and dry beans that underwent a dramatic range expansion in North America during the first decade of the 21st century. Research into the population genetics of this species has been hindered by a lack of genetic markers. The transcriptome of adult male S. albicosta was partially sequenced using Illumina sequencing-by-synthesis. Assembly of the sequence reads yielded 16,847 transcript sequences, of which 6,631 could be assigned a putative function. A search for single nucleotide polymorphisms (SNPs) identified 2,487 candidate SNPs distributed among 1,265 …

Susceptibility Of The Fall Armyworm, Spodoptera Frugiperda (Lepidoptera: Noctuidae), At Santa Isabel, Puerto Rico, To Different Insecticides, Difabachew K. Belay, Randy M. Huckaba, John E. Foster

Department of Entomology: Faculty Publications

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is a polyphagous migratory pest, which is endemic to the Western Hemisphere and attacks more than 80 plant species including maize, sorghum, cotton, rice, millet, peanut, alfalfa, and other cultivated and wild plant species. Presence of multiple generations and the ability to migrate and feed on a wide range of host plants makes FAW one of the most severe economic pests throughout the Western Hemisphere. In corn, yield losses due to FAW damage can reach up to 32% in the United States and 45–60% in Nicaragua. Insecticides are used as major …

Insecticidal Control Of Bemisia Tabaci (Hemiptera: Aleyrodidae) Transmitting Carlavirus On Soybeans And Detection Of The Virus In Alternate Hosts, Difabachew K. Belay, Randy M. Huckaba, Axel M. Ramirez, Jose C. V. Rodrigues, John E. Foster

Department of Entomology: Faculty Publications

A Carlavirus transmitted by Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is an important disease of soybean nurseries in Puerto Rico causing substantial germplasm losses. Insecticide bioassay experiments were conducted at Dow AgroSciences (DAS) Research Station, Santa Isabel, Puerto Rico, either by spraying insecticides on B. tabaci infested soybean leaves or introducing B. tabaci adults onto insecticide-sprayed soybean leaves. Moreover, host plants were surveyed to detect the virus in overwintering hosts that serve as a source of inoculums. The direct spray experiment showed that Nuprid 2F (Imidacloprid), Capture 2 EC (Bifenthrin), Thionex (Endosulfan), Lannate LV (Methomyl), and Dimethoate gave good level ( …

Genetic Differentiation Of Western Corn Rootworm Populations (Coleoptera: Chrysomelidae) Relative To Insecticide Resistance, Hong Chen, Haichuan Wang, Blair D. Siegfried

Department of Entomology: Faculty Publications

Abstract

As the single most important pest of field corn, Zea mays L., throughout most of the Corn Belt, the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), has undergone repeated selection for resistance to a variety of insecticides that persist widely among Nebraska populations. In this study, we used 11 microsatellite markers to genotype two populations with high levels of resistance to methyl-parathion and aldrin (Polk and Stromsburg), two populations with low and intermediate levels of resistance (Mead and Clay Center) from Nebraska, and one population from outside the Corn Belt (Safford, Arizona). The genetic diversity measured by …

Bean Leaf Beetle (Coleoptera: Chrysomelidae) And Bean Pod Mottle Virus In Soybean: Biology, Ecology, And Management, Buyung A. R. Hadi, Jeffrey D. Bradshaw, Marlin E. Rice, John J. Hill

Department of Entomology: Faculty Publications

Bean leaf beetle, Cerotoma trifurcata (Förster), is a pest of soybean found in many production areas in the United States. The bean leaf beetle larvae feed on soybean root nodules, whereas the adults feed on the above ground parts of soybean such as cotyledon, leaves, and pods. Bean leaf beetle is also a very efficient vector of Bean pod mottle virus, a widespread virus of soybean in the south and southeastern United States with recent expansion into the north central region of the country. This article summarizes bean leaf beetle biology, ecology, and its impact on soybean production in the …

Spatial Genetic Variation Among Spodoptera Frugiperda (Lepidoptera: Noctuidae) Sampled From The United States, Puerto Rico, Panama, And Argentina, Difabachew K. Belay, Pete L. Clark, Steven R. Skoda, David J. Isenhour, Jaime Molina-Ochoa, Claudia Gianni, John E. Foster

Department of Entomology: Faculty Publications

Spatial genetic variability of the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), was studied by collecting samples from 31 locations in the United States, Argentina, Panama, and Puerto Rico, and then using amplified fragment length polymorphism to detect genetic variation. Analysis of molecular variance showed significant genetic variation in fall armyworm among all (28%) sample locations and individuals within (71%) sample locations; genetic variation of fall armyworm was minimal between sample locations grouped into regions. The pairwise fixation index (F_ST) comparisons showed significant genetic differentiation (0.288) among the 31 locations. However, dendrograms of results from cluster …

Mortality Impact Of Mon863 Transgenic Maize Roots On Western Corn Rootworm Larvae In The Field, T. L. Clark, D. L. Frank, B. W. French, Lance J. Meinke, D. Moellenbeck, T. T. Vaughn, B. E. Hibbard

Department of Entomology: Faculty Publications

Mortality of western corn rootworm (Diabrotica virgifera virgifera LeConte) due to feeding on MON863 transgenic maize (Zea mays L.) expressing the Cry3Bb1 protein was evaluated at three Missouri sites in both 2003 and 2004 and at one site each in South Dakota, Nebraska, and Iowa in 2004. To do this, survivorship relative to survivorship on isoline maize (i.e., the same genetic background, but without Cry3Bb1) was evaluated. Comparisons were made using low (1650–2500 eggs/m) and high (3300–3500 eggs/m) western corn rootworm egg densities. Significantly fewer beetles were recovered from MON863 than from isoline maize. Emergence from MON863 as …

Distribution Of Genes And Repetitive Elements In The Diabrotica Virgifera Virgifera Genome Estimated Using Bac Sequencing, Brad S. Coates, Analiza P. Alves, Haichuan Wang, Kimberly K. O. Walden, B. Wade French, Nicholas J. Miller, Craig A. Abel, Hugh M. Robertson, Thomas W. Sappington, Blair D. Siegfried

Department of Entomology: Faculty Publications

Feeding damage caused by the western corn rootworm, Diabrotica virgifera virgifera, is destructive to corn plants in North America and Europe where control remains challenging due to evolution of resistance to chemical and transgenic toxins. A BAC library, DvvBAC1, containing 109,486 clones with 104 ± 34.5 kb inserts was created, which has an ~4.56X genome coverage based upon a 2.58 Gb (2.80 pg) flow cytometry-estimated haploid genome size. Paired end sequencing of 1037 BAC inserts produced 1.17Mb of data (~0.05% genome coverage) and indicated ~9.4 and 16.0% of reads encode, respectively, endogenous genes and transposable elements (TEs). …

Using Sex Pheromone Traps In The Decision-Making Process For Pesticide Application Against Fall Armyworm (Spodoptera Frugiperda [Smith] [Lepidoptera: Noctuidae]) Larvae In Maize, Ivan Cruz, Maria De Lourdes Corrêa Figueiredo, Rafael Braga Da Silva, Ivana Fernandes Da Silva, Cristiane De Souza Paula, John E. Foster

Department of Entomology: Faculty Publications

The fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), is a major pest of maize and frequently demands control measures. The timing of insecticide application is a key factor in determining its efficiency, so an experiment was designed to investigate this. Application of insecticide was based on three criteria: (i) the number of trap-caught moths in a Delta-type trap with a commercial sex pheromone lure placed in the center of the target area, soon after plant emergence; (ii) the percentage of plants exhibiting pinhole-type damage (10% or 20%), and (iii) the percentage of plants exhibiting shot hole–type damage (10% or 20%) …

Larval Survival And Plant Injury Of Cry1ab-Susceptible, -Resistant, And -Heterozygous Genotypes Of The Sugarcane Borer On Transgenic Corn Containing Single Or Pyramided Bt Genes, David S. Wangila, B. Rogers Leonard, Yaoyu Bai, Graham P. Head, Fangneng Huang

Department of Entomology: Faculty Publications

Transgenic corn (Zea mays L.) products expressing multiple Bt proteins targeting a same group of insect pests have become commercially available in the U.S. The first commercialized pyramided Bt corn technologies for managing lepidopteran pests include Genuity® VT Triple Pro™ and Genuity® SmartStax™. In this study, larval survival and plant injury of Cry1Ab-susceptible (Cry1Ab-SS), -resistant (Cry1Ab-RR), and -heterozygous (Cry1Ab-RS) genotypes of the sugarcane borer, Diatraea saccharalis F., on five commercial corn hybrids were evaluated in a leaf tissue bioassay and two greenhouse trials during 2010–2011. The five hybrids included two non-Bt corn and three Bt corn hybrids representing three …

Susceptibility Of Cry1ab Maize-Resistant And -Susceptible Strains Of Sugarcane Borer (Lepidoptera: Crambidae) To Four Individual Cry Proteins, Liping Zhang, Fangneng Huang, B. Rogers Leonard, Mao Chen, Thomas Clark, Yu Cheng Zhu, David S. Wangila, Fei Yang, Ying Niu

Department of Entomology: Faculty Publications

Sugarcane borer, Diatraea saccharalis (F.), is a major target of Bt maize in South America and many areas of the US mid-south region. Six laboratory strains of D. saccharalis were established from six single-pair F2 families possessing major resistance alleles to Cry1Ab maize hybrids. Susceptibility of the six strains was evaluated on diet treated with each of four purified trypsin-activated Bt proteins, Cry1Ab, Cry1Aa, Cry1Ac, and Cry1F. Bt susceptibility of the six strains was compared with that of known Cry1Ab-susceptible and -resistant strains of D. saccharalis. At least two of the six strains demonstrated a similar level (>526-fold) …

Rna Interference As A Method For Target-Site Screening In The Western Corn Rootworm, Diabrotica Virgifera Virgifera, Analiza P. Alves, Marce D. Lorenzen, Richard W. Beeman, John E. Foster, Blair D. Siegfried

Department of Entomology: Faculty Publications

To test the efficacy of RNA interference (RNAi) as a method for target-site screening in Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) larvae, genes were identified and tested for which clear RNAi phenotypes had been identified in the Coleopteran model, Tribolium castaneum. Here the cloning of the D. v. vergifera orthologs of laccase 2 (DvvLac2) and chitin synthase 2 (DvvCHS2) is reported. Injection of DvvLac2-specific doublestranded RNA resulted in prevention of post-molt cuticular tanning, while injection of DvvCHS2- specific dsRNA reduced chitin levels in midguts. Silencing of both DvvLac2 and DvvCHS2 was confirmed by RT-PCR and quantitative RT-PCR. As in T. …

Genetic Variability Of The European Corn Borer, Ostrinia Nubilalis, Suggests Gene Flow Between Populations In The Midwestern United States, Jeffrey T. Krumm, Thomas E. Hunt, Steven R. Skoda, Gary L. Hein, Donald J. Lee, Pete L. Clark, John E. Foster

Department of Entomology: Faculty Publications

The European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), is a widely distributed and serious economic pest to corn production in the U.S. Genetic variability of O. nubilalis was studied in 18 sub-populations in the upper Midwestern United States using amplified fragment length polymorphism. The relatively low GST values indicate that more variation exists within populations than between populations. High gene flow (Nm) values were indicated across the entire O. nubilalis population; the lowest degree of gene flow was in the northern samples (Nm = 1.96) and the highest degree of gene flow was in the southern samples (Nm = …

Coordinated Diabrotica Genetics Research: Accelerating Progress On An Urgent Insect Pest Problem, Thomas W. Sappington, Blair D. Siegfried, Thomas Guillemaud

Department of Entomology: Faculty Publications

Diabrotica spp. (western, northern, and Mexican corn rootworms) represent the main pest complex of continuous field corn, Zea mays (L.), in North America. The western corn rootworm, Diabrotica virgifera virgifera LeConte, also has become the main pest of continuous corn in Central and Southeastern Europe since its introduction near Belgrade 15–20 years ago, and it represents a major risk to Western Europe. It has already caused economic losses in Eastern Europe, and Western countries such as France have committed large expenditures for containment and/or eradication.

Rootworm larvae feed on corn roots, and damaged plants are more susceptible to drought and …

Effects Of Aphid (Homoptera) Abundance And Surrounding Vegetation On The Encounter Rate Of Coccinellidae (Coleoptera), Chrysopidae (Neuroptera), And Nabidae (Hemiptera) In Alfalfa, James C. Kriz, Stephen D. Danielson, James R. Brandle, Erin E. Blankenship, Geoff M. Henebry

Department of Entomology: Faculty Publications

Predaceous insect encounter rate was measured in 21 southeast Nebraska alfalfa fields through weekly sweep net sampling during 2002-03. The most frequently encountered predaceous insect families were Coccinellidae (Coleoptera), Nabidae (Hemiptera), and Chrysopidae (Neuroptera). The study used multiple regression analysis to examine the effect of aphid abundance and the surrounding vegetative patch composition on predaceous insect abundance. In 2002, Hippodamia parenthesis Say was encountered more frequently in fields with lower aphid abundances, and Hippodamia convergens Guerin-Meneville, Coccinella septempunctata L., and Nabis americoferus Carayon were encountered more frequently in fields with higher aphid abundances. In 2003, Coleomegilla maculata DeGeer was encountered …

Response Of Lowland Rice Plants To Simulated Insect Defoliation In West Africa, I. O. Oyediran, E. A. Heinrichs

Department of Entomology: Faculty Publications

Field experiments were conducted to investigate the impact of simulated insect-caused defoliation on irrigated rice. Defoliation levels tested were 0% (control), 25% defoliation at 21 days after transplanting (dat), 25% defoliation at 41 dat, 25% defoliation at 21 and 42 dat, 50% defoliation at 21 dat, 50% defoliation at 42 dat, 75% defoliation at 21 dat, 75% defoliation at 42 dat, 75% defoliation at 21 and 42 dat, 100% defoliation at 21 dat, and 100% defoliation at 21 and 42 dat. Tiller height, total number of tillers, percent panicle-bearing tillers, weight of 100 grains, and grain yields were recorded. The …

Arthropod Populations And Rice Yields In Direct-Seeded And Transplanted Lowland Rice In West Africa, I. O. Oyediran, E. A. Heinrichs

Department of Entomology: Faculty Publications

Two methods for planting rice in irrigated lowland were evaluated during the wet seasons of 1994 and 1995 to determine their effect on rice arthropod numbers, insect-caused rice plant damage, and rice grain yield. The six treatments tested were: hand transplanting of seedlings at spacings of 14 cm × 14 cm, 20 cm × 20 cm, and 30 cm × 30 cm; and direct-seeding of rice at 60 kg seeds ha^–1, 90 kg seeds ha^–1, and 120 kg seeds ha^–1. The most abundant arthropods in the study were the diopsid flies, Diopsis longicornis Maquart …