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a novel bacillus thuringiensis (ps149b1) containing a cry34ab1/cry35ab1 binary toxin specific for the western corn rootworm diabrotica virgifera virgifera leconte forms ion channels in lipid membranes.the binary bacillus thuringiensis ps149b1 insecticidal crystal (cry) protein is comprised of two components, cry34ab1, a 14-kda protein, and cry35ab1, a 44-kda protein, the combination of which forms a novel binary toxin active on western corn rootworm larvae. the permeabilizing behavior of the native binary toxin and its two individual components expressed as recombinant proteins was studied using calcein efflux determination in liposomes and by ion channel activity measurements in planar lipid ...200415379574
baseline susceptibility of western corn rootworm (coleoptera: crysomelidae) to cry3bb1 bacillus thuringiensis toxin.susceptibility to cry3bb1 toxin from bacillus thuringiensis (bt) was determined for western corn rootworm, diabrotica virgifera virgifera leconte, neonates from both laboratory and field populations collected from across the corn belt. rootworm larvae were exposed to artificial diet treated with increasing cry3bb1 concentrations, and mortality and growth inhibition were evaluated after 4-7 d. the range of variation in bt susceptibility indicated by growth inhibition was similar to that indicated ...200516156586
use of transgenic plants to measure insect herbivore movement.use of ingested transgenic corn tissue as a marker for measuring movement of adult diabrotica virgifera virgifera (leconte) (coleoptera: chrysomelidae; western corn rootworm) was investigated. laboratory observations of beetles feeding on corn foliage, pollen, silks, or soybean foliage provided background on feeding patterns. the interval between food consumption and its appearance in feces (gut passage time) ranged from 102.7 +/- 11 min for soybean foliage to 56.7 +/- 2.9 min for corn silks. in ...200314977111
foraging resources of adult mexican corn rootworm (coleoptera: chrysomelidae) in bell county, texas.pollen analyses were used to determine pollen foraging resources of adult mexican corn rootworms, diabrotica virgifera zeae krysan & smith, captured near temple, bell county, tx, in 1996 and 1997. in 1996, adult mexican corn rootworms were captured in a corn, zea mays l., field. in 1997, nine locations outside of cornfields were added. overall, 92% of the beetles (n = 1,323) contained pollen. more than 142,000 pollen grains were counted, representing 45 families, 63 genera, and 27 species. overa ...200010902309
an in-gel assay of a recombinant western corn rootworm (diabrotica virgifera virgifera) cysteine proteinase expressed in yeast. 200010860514
effect of cry3bb1-expressing transgenic corn on plant-to-plant movement by western corn rootworm larvae (coleoptera: chrysomelidae).dispersal of larvae of the western corn rootworm, diabrotica virgifera virgifera leconte, in specific combinations of transgenic corn expressing the cry3bb1 protein and nontransgenic, isoline corn was evaluated in a 2-yr field study. in total, 1,500 viable western corn rootworm eggs were infested in each subplot. each year, plant damage and larval recovery were evaluated among four pedigree combinations (straight transgenic; straight nontransgenic corn; nontransgenic corn with a transgenic centr ...200516156562
effects of a potato cysteine proteinase inhibitor on midgut proteolytic enzyme activity and growth of the southern corn rootworm, diabrotica undecimpunctata howardi (coleoptera: chrysomelidae).the major proteinase activity in extracts of larval midguts from the southern corn rootworm (scr), diabrotica undecimpunctata howardi, was identified as a cysteine proteinase that prefers substrates containing an arginine residue in the p1 position. gelatin-zymogram analysis of the midgut proteinases indicated that the artificial diet-fed scr, corn root-fed scr, and root-fed western corn rootworms (diabrotica virgifera virgifera) possess a single major proteinase with an apparent molecular mass ...200211886775
evaluation of conventional resistance to european corn borer (lepidoptera: crambidae) and western corn rootworm (coleoptera: chrysomelidae) in experimental maize lines developed from a backcross breeding program.plant resistance is a promising control method for the two most damaging insect pests of maize, zea mays l.: the european corn borer, ostrinia nubilalis (hübner), and the western corn rootworm diabrotica virgifera virgifera leconte. fifteen experimental lines of maize, derived from a backcross breeding program designed to introgress resistance to european corn borer from peruvian maize into two u.s. corn belt adapted inbred lines, were evaluated for resistance to european corn borer and western ...200011142317
novel bacillus thuringiensis binary insecticidal crystal proteins active on western corn rootworm, diabrotica virgifera virgifera leconte.a new family of insecticidal crystal proteins was discovered by screening sporulated bacillus thuringiensis cultures for oral activity against western corn rootworm (wcr) larvae. b. thuringiensis isolates ps80jj1, ps149b1, and ps167h2 have wcr insecticidal activity attributable to parasporal inclusion bodies containing proteins with molecular masses of ca. 14 and 44 kda. the genes encoding these polypeptides reside in apparent operons, and the 14-kda protein open reading frame (orf) precedes the ...200211872461
insecticidal proteins from bacillus thuringiensis protect corn from corn rootworms.field tests of corn co-expressing two new delta-endotoxins from bacillus thuringiensis (bt) have demonstrated protection from root damage by western corn rootworm (diabrotica virgifera virgifera leconte). the level of protection exceeds that provided by chemical insecticides. in the bacterium, these proteins form crystals during the sporulation phase of the growth cycle, are encoded by a single operon, and have molecular masses of 14 kda and 44 kda. corn rootworm larvae fed on corn roots express ...200111433280
western corn rootworm (coleoptera: chrysomelidae) beetle emergence from weedy cry3bbl rootworm-resistant transgenic corn.three greenhouse experiments were conducted to evaluate western corn rootworm, diabrotica virgifera virgifera leconte, beetle emergence from individual pots containing glyphosate-tolerant transgenic corn, zea mays l., expressing the cry3bbl endotoxin from the soil bacterium bacillus thuringiensis berliner (mon863), nontransgenic glyphosate-tolerant isoline corn, grassy weeds (giant foxtail, setariafaberi r.a.w. herrm; and large crabgrass, digitaria sanguinalis (l.) scop.), and combinations there ...200516334339
effect of bacillus thuringiensis cry3bb1 protein on the feeding behavior and longevity of adult western corn rootworms (coleoptera: chrysomelidae).the first transgenic corn hybrids expressing the bacillus thuringiensis (bt) cry3bb1 protein to control corn rootworm (diabrotica spp.) larvae were registered for commercial use in 2003. this study was conducted to investigate the effect of cry3bb1 protein in combination with a cucurbitacin bait on adult feeding and longevity of both organophosphate-resistant and -susceptible western corn rootworms, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae). in choice and no-choice tests ...200616813332
economic analysis of dynamic management strategies utilizing. transgenic corn for control of western corn rootworm (coleoptera: chrysomelidae).we studied management strategies for western corn rootworm, diabrotica virgifera virgifera leconte, using transgenic corn, zea mays l., from both a biological and an economic perspective. in areas with and without populations adapted to a 2-yr rotation of corn and soybean (rotation-resistant), the standard management strategy was to plant 80% of a cornfield (rotated and continuous) to a transgenic cultivar each year. in each area, we also studied dynamic management strategies where the proportio ...200516022329
characterization of cry34/cry35 binary insecticidal proteins from diverse bacillus thuringiensis strain collections.bacillus thuringiensis crystal proteins of the cry34 and cry35 classes function as binary toxins showing activity on the western corn rootworm, diabrotica virgifera virgifera leconte. we surveyed 6,499 b. thuringiensis isolates by hybridization for sequences related to cry35a genes, identifying 78 strains. proteins of the appropriate molecular mass (ca. 44 kda) for cry35 were observed in 42 of the strains. full-length, or nearly full-length, sequences of 34 cry34 genes and 16 cry35 genes were al ...200515811999
first report of the western corn rootworm diabrotica virgifera in belgium. 200415759426
binary toxins from bacillus thuringiensis active against the western corn rootworm, diabrotica virgifera virgifera leconte.the western corn rootworm, diabrotica virgifera virgifera leconte, is a significant pest of corn in the united states. the development of transgenic corn hybrids resistant to rootworm feeding damage depends on the identification of genes encoding insecticidal proteins toxic to rootworm larvae. in this study, a bioassay screen was used to identify several isolates of the bacterium bacillus thuringiensis active against rootworm. these bacterial isolates each produce distinct crystal proteins with ...200415294828
role of egg density on establishment and plant-to-plant movement by western corn rootworm larvae (coleoptera: chrysomelidae).the effect of egg density on establishment and dispersal of larvae of the western corn rootworm, diabrotica virgifera virgifera leconte, was evaluated in a 3-yr field study. implications of these data for resistance management plans for bt crops are discussed. viable egg levels of 100, 200, 400, 800, and 1600 eggs per infested plant were evaluated in 2000, 2001, and 2002. a 3200 viable egg level was also tested in 2001 and 2002. all eggs were infested on one plant per subplot in a field that was ...200415279266
population patterns of mexican corn rootworm (coleoptera: chrysomelidae) adults indicated by different sampling methods.the mexican corn rootworm, diabrotica virgifera zeae krysan & smith, is a serious pest of corn, zea mays l., in several areas of texas. recent demonstrations of areawide adult control suggest this tactic has promise for rootworm management, but additional information regarding treatment thresholds and sampling methodology is needed. in 2000 and 2001 we examined the influence of distance into the field on rootworm captures by crw and pherocon am traps, the fidelity of trap captures to population ...200415154499
disruption of host location of western corn rootworm larvae (coleoptera: chrysomelidae) with carbon dioxide.elevated concentrations of carbon dioxide (co2) prevented neonate larvae of the western corn rootworm, diabrotica virgifera virgifera leconte, from locating the roots of growing corn in behavioral bioassays conducted in soil tubs. when co2 was pumped into one end of a soil tub, significantly more larvae were recovered from soil at the treated end than from soil around a growing corn plant at the opposite end of the tub. in controls with ambient air pumped into one end of a soil tub, significantl ...200415154452
orientation disruption of diabrotica virgifera virgifera in maize by a liquid mca formulation released from paper squares in the banat region of serbia and montenegro.serbia-montenegro, formerly the republic of yugoslavia, is the first european country where diabrotica virgifera virgifera le conte (col.: chrysomelidae) (d.v.v.) was reported in 1992 as an invasive alien pest species, baca (1993), camprag and baca, (1995): from a focal point near belgrade airport, the maize pest quickly spread in all directions reaching the economic threshold in a number of surrounding countries around 1995. the field experiments described took place in the banat region east of ...200315149097
distribution patterns of mca-coated granules aerially applied to corn fields of southern hungary between 2000 and 2002.field studies in corn (zea mays l.) were conducted to evaluate distribution patterns of 4-methoxy-cinnamaldehyde (mca) coated corn grits after aerial application with a dromader fixed wing aircraft. the kairomone mimic mca is synthetically available and a quite specific and efficient adult attractant for the invasive alien maize pest western corn rootworm (wcr) diabrotica virgifera virgifera leconte. orientation disruptive properties of mca for wcr when applied at unphysiologically high concentr ...200315149096
time of planting and choice of maize hybrids in controlling wcr (diabrotica virgifera virgifera le conte) in serbia and montenegro.effects of the length of growing season of maize hybrids (fao maturity groups 400, 500, 600 and 700) and planting dates on the maize crop, as an attractive supplemental feeding for western corn rootworm (wcr) beetles and larval survival, were observed in two locations of south banat, during a three-year (1997-1999) and a two-year period (2001 and 2002). the feeding attraction of the maize crop for wcr beetles and survival of larvae were evaluated in dependency of the variable "plant lodging". th ...200315149095
introduction of diabrotica virgifera virgifera into the old world and its consequences: a recently acquired invasive alien pest species on zea mays from north america.diabrotica v. virgifera leconte (coleoptera: chrysomelidae), (in short d.v.v.), with common name western corn rootworm, is endemic to the new world. originating in the regions from south america to mexico where it was in biological equilibrium with its natural enemies, predators and pathogens, it moved north with its food plants. probably due to human agricultural farm practices with preference for monoculture of maize, the insect found open niches for expanding to the midwestern us where lecont ...200315149091
enhancement of bacillus thuringiensis cry3aa and cry3bb toxicities to coleopteran larvae by a toxin-binding fragment of an insect cadherin.the cry3aa and cry3bb insecticidal proteins of bacillus thuringiensis are used in biopesticides and transgenic crops to control larvae of leaf-feeding beetles and rootworms. cadherins localized in the midgut epithelium are identified as receptors for cry toxins in lepidopteran and dipteran larvae. previously, we discovered that a peptide of a toxin-binding cadherin expressed in escherichia coli functions as a synergist for cry1a toxicity against lepidopteran larvae and cry4 toxicity against dipt ...200919329664
characterisation of cysteine proteinases responsible for digestive proteolysis in guts of larval western corn rootworm (diabrotica virgifera) by expression in the yeast pichia pastoris.cysteine proteinases are the major class of enzymes responsible for digestive proteolysis in western corn rootworm (diabrotica virgifera), a serious pest of maize. a larval gut extract hydrolysed typical cathepsin substrates, such as z-phe-arg-amc and z-arg-arg-amc, and hydrolysis was inhibited by z-phe-tyr-dmk, specific for cathepsin l. a cdna library representing larval gut tissue mrna contained cysteine proteinase-encoding clones at high frequency. sequence analysis of 11 cysteine proteinase ...200415041015
discovery and characterization of sip1a: a novel secreted protein from bacillus thuringiensis with activity against coleopteran larvae.bioassay screening of bacillus thuringiensis culture supernatants identified strain eg2158 as having larvicidal activity against colorado potato beetle (leptinotarsa decemlineata) larvae. ion-exchange fractionation of the eg2158 culture supernatant resulted in the identification of a protein designated sip1a (secreted insecticidal protein) of approximately 38 kda having activity against colorado potato beetle (cpb). an oligonucleotide probe based on the n-terminal sequence of the purified sip1a ...200616489451
rapid digestion of cry34ab1 and cry35ab1 in simulated gastric fluid.two genes were identified in bacillus thuringiensis berliner (bt) that code for the proteins that comprise a cry34ab1/cry35ab1 binary insecticidal crystal protein. maize, zea mays l., plants have been transformed to express the cry34ab1/cry35ab1 proteins, and as a result, these plants are resistant to attack by western corn rootworm, diabrotica virgifera virgifera leconte, a major pest in the midwestern corn-growing area of the u.s.a. as part of the safety assessment for the proteins, digestibil ...200314582981
binary insecticidal crystal protein from bacillus thuringiensis, strain ps149b1: effects of individual protein components and mixtures in laboratory bioassays.a family of novel binary insecticidal crystal proteins, with activity against western corn rootworm, diabrotica virgifera virgifera leconte, was identified from bacillus thuringiensis berliner. a binary insecticidal crystal protein (bicp) from b. thuringiensis strain ps149b1 is composed of a 14-kda protein (cry34abl) and a 44-kdaprotein (cry35ab1). these proteins have been co-expressed in transgenic maize plants, zea mays l., and effectively control western corn rootworm larvae under field condi ...200212076012
cadherin fragments from anopheles gambiae synergize bacillus thuringiensis cry4ba's toxicity against aedes aegypti larvae.a peptide from cadherin agcad1 of anopheles gambiae larvae was reported as a synergist of bacillus thuringiensis subsp. israelensis cry4ba's toxicity to the anopheles mosquito (g. hua, r. zhang, m. a. abdullah, and m. j. adang, biochemistry 47:5101-5110, 2008). we report that cr11 to the membrane proximal extracellular domain (mped) (cr11-mped) and a longer peptide, cr9 to cr11 (cr9-11), from agcad1 act as synergists of cry4ba's toxicity to aedes aegypti larvae, but a diabrotica virgifera virgif ...200919801487
diabrotica virgifera virgifera in eastern slovenia: increasing population trend 2005.the first invasion of the western corn rootworm (wcr), diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae) into slovenia was recorded in 2003. a few beetles were found in the western province of slovenia near italy. more beetles were detected in the eastern district of prekmurje bordering austria, hungary and croatia. while the western population remained the same in 2005, the eastern population increased considerably. by means of the very sensitive metcalf sticky trap baited with ...200617385526
interactions of alternate hosts, postemergence grass control, and rootworm-resistant transgenic corn on western corn rootworm (coleoptera: chrysomelidae) damage and adult emergence.field studies were conducted in 2003 and 2004 to determine the effects of grassy weeds, postemergence grass control, transgenic rootworm-resistant corn, zea mays l., expressing the cry3bb1 endotoxin and glyphosate herbicide tolerance (bt corn), and the interactions of these factors on western corn rootworm, diabrotica virgifera virgifera leconte, damage and adult emergence. three insect management tactics (bt corn, its nontransgenic isoline, and isoline plus tefluthrin) were evaluated with two w ...200717461083
diabrotica virgifera virgifera in switzerland: future invasion trend into germany via transalpine, terrestrial routes.the western corn rootworm diabrotica v.virgifera (d.v.v.) (coleoptera:chrysomelidae) is endemic to the new world. on at least 3 occasions, it invaded europe (miller et al. 2005). the first of these invasions took place in or before 1992 (baca 1993) to belgrade, serbia, and gave rise to a rapidly expanding beetle population in se europe. its larvae are causing economic damage to zea mays for the last ten years, with increasing severity both in acreage and density. meanwhile germany is still witho ...200617385500
diabrotica virgifera virgifera (coleoptera: chrysomelidae) larval feeding behavior on transgenic maize (mon 863) and its isoline.diabrotica species (coleoptera: chrysomelidae) larval behavior studies have posed a challenge to researchers because of the subterranean life cycle of this pest. to fully understand how the western corn rootworm, diabrotica virgifera virgifera leconte, injures the maize, zea mays l., root system, its behavior must be studied. for example, larvae that can detect an area of the root that has a lower amount of toxin, whether from an insecticide or a transgenic maize plant, have an increased chance ...200616813304
genetic variation in geographical populations of western and mexican corn rootworm.genetic variation in the nuclear rdna its1 region of western corn rootworm, diabrotica virgifera virgifera (wcr), and mexican corn rootworm, d. v. zeae (mcr) was studied. two sites were detected which differentiated wcr and mcr in the 642-base sequence. polymerase chain reaction-restriction fragment length polymorphism (pcr-rflp) analysis of the first internal transcribed spacer region (its1) sequence revealed no variation within or among the twelve wcr and two mcr populations. pcr-rflp of 75% o ...199910620046
the role of wolbachia bacteria in reproductive incompatibilities and hybrid zones of diabrotica beetles and gryllus crickets.a rickettsial bacterium in the genus wolbachia is the cause of a unidirectional reproductive incompatibility observed between two major beetle pests of maize, the western corn rootworm, diabrotica virgifera virgifera, and the mexican corn rootworm, d. v. zeae. these subspecies are allopatric except for two known regions of sympatry in texas and mexico. we demonstrate that populations of d. v. virgifera, with the exception of two populations in southern arizona, are infected with a strain of wolb ...19979326628
field measures of western corn rootworm (coleoptera: chrysomelidae) mortality caused by cry34/35ab1 proteins expressed in maize event 59122 and implications for trait durability.maize, zea mays l., has been transformed to express the cry34ab1 and cry35ab1 proteins from bacillus thuringiensis strain ps149b1. these two proteins act together as a binary insecticidal protein that is effective against corn rootworm (coleoptera: chrysomelidae) species. the design of the resistance management plan to preserve the long-term durability of this trait largely depends on the level of rootworm mortality induced by cry34/35ab1 corn rootworm-protected maize (frequently referred to as ...200616937696
the western corn rootworm diabrotica virgifera virgifera en route to germany.the western corn rootworm diabrotica virgifera virgifera leconte (col.:chrysomelidae) (d.v.v.) is one of the most important maize pests in north america. ever since its invasion into europe and its detection near belgrade airport by baca in 1993 it quickly spread all over southeastern europe and is now advancing towards central europe. up until summer 2004 considered free of d.v.v., germany is, with the exception of its northern and northeastern borders, surrounded by countries with proven d.v.v ...200516628903
a global approach to resistance monitoring.transgenic crops producing insecticidal toxins from the bacterium bacillus thuringiensis (bt) have been grown in many parts of the world since 1996. in the united states, the environmental protection agency (epa) has required that industry submit insect resistance management (irm) plans for each bt corn and cotton product commercialized. a coalition of stakeholders including the epa, usda, academic scientists, industry, and grower organizations have cooperated in developing specific irm strategi ...200717467005
planting patterns of in-field refuges observed for bt maize in minnesota.the u.s. environmental protection agency (usepa) requires the use of nontransgenic refuges to slow the evolution of insect resistance to transgenic crops. in-field refuges, or refuges that are planted within the same field as the transgenic crop, are allowed; however, these refuges are required to be at least four rows wide. we described in-field planting patterns used by growers for both crylab [against ostrinia nubilalis (hübner)] and cry3bb (against diabrotica virgifera virgifera leconte) mai ...201020857753
toxicity of chromobacterium subtsugae to southern green stink bug (heteroptera: pentatomidae) and corn rootworm (coleoptera: chrysomelidae).diabrotica spp. (coleoptera: chrysomelidae) beetles and southern green stink bugs, nezara viridula (l.) (heteroptera: pentatomidae), are pests on corn, zea mays l., and soybean, glycine max (l.) merr., as well as on cucurbits. control of these insects has depended on chemicals. an alternative to chemical control is the use of biologicals. use of bacteria, fungi, viruses, pheromones, and metabolites to control these insects can potentially improve resistance management and reduce pesticide use. o ...200717598525
insect pest densities across site-specific management zones of irrigated corn in northeastern colorado.the ability to manage insect pests in a site-specific manner is hindered by the costs and time required to describe pest densities and distributions. the purpose of this study was to determine whether insect pest distributions are related to site-specific management zones (ssmzs). site-specific management zones, as described in this study, delineate fields into three zones of similar yield potential: high, medium, and low productivity. if insect densities vary across ssmzs, it is possible that m ...200717598539
a novel cadherin-like gene from western corn rootworm, diabrotica virgifera virgifera (coleoptera: chrysomelidae), larval midgut tissue.a cadherin-like gene associated with larval midgut tissues was cloned from western corn rootworm (diabrotica virgifera virgifera: coleoptera), an economically important agricultural pest in north america and europe and the primary target pest species for corn hybrids expressing cry3 toxins from bacillus thuringiensis (bt). the full-length cdna (5371 bp in length) encodes an open reading frame for a 1688 amino acid polypeptide. the putative protein has similar architecture to cadherin-like protei ...200717725800
mortality of western corn rootworm larvae on mir604 transgenic maize roots: field survivorship has no significant impact on survivorship of f1 progeny on mir604.mortality of western corn rootworm, diabrotica virgifera virgifera leconte, larvae due to mir604 transgenic corn, zea mays l., expressing the modified cry3a (mcry3a) protein relative to survivorship on corn with the same genetic background without the gene (isoline corn) was evaluated at three missouri sites in both 2005 and 2006. we made these comparisons by using wild-type western corn rootworm at three different egg densities (6,000, 3,000, and 1,500 eggs per m) so that the role of density-de ...201021309243
control of coleopteran insect pests through rna interference.commercial biotechnology solutions for controlling lepidopteran and coleopteran insect pests on crops depend on the expression of bacillus thuringiensis insecticidal proteins, most of which permeabilize the membranes of gut epithelial cells of susceptible insects. however, insect control strategies involving a different mode of action would be valuable for managing the emergence of insect resistance. toward this end, we demonstrate that ingestion of double-stranded (ds)rnas supplied in an artifi ...200717982443
papain-like cysteine proteases: key players at molecular battlefields employed by both plants and their invaders.papain-like cysteine proteases (plcps) play crucial roles in plant-pathogen/pest interactions. during these parasitic interactions, plcps act on non-self substrates, provoking the selection of counteracting inhibitors and other means to evade proteolysis. we review examples of plcps acting on molecular battlefields in the extracellular space, plant cytoplasm and herbivore gut. examples are maize mir1 (maize inbred resistance 1), tomato rcr3 (required for cladosporium resistance-3), pseudomonas a ...200818705889
increased survival of western corn rootworm on transgenic corn within three generations of on-plant greenhouse selection.to delay evolution of insect resistance to transgenic crops producing bacillus thuringiensis (bt) toxins, nearby "refuges" of host plants not producing bt toxins are required in many regions. such refuges are expected to be most effective in slowing resistance when the toxin concentration in bt crops is high enough to kill all or nearly all insects heterozygous for resistance. however, bt corn, zea mays, introduced recently does not meet this "high-dose" criterion for control of western corn roo ...200819047626
molecular level lignin patterns of genetically modified bt-maize mon88017 and three conventional varieties using tetramethylammonium hydroxide (tmah)-induced thermochemolysis.bt-maize mon88017, its near-isogenic line dkc5143, and the two conventional varieties dk315 and benicia were subjected to tetramethylammonium hydroxide (tmah)-induced thermochemolysis to reveal molecular level lignin patterns. mon88017 is genetically modified to express the cry3bb1 protein aimed at the western corn rootworm diabrotica virgifera virgifera, a serious threat for european maize production. the results indicated that roots of the bt-maize were characterized by a slightly enhanced tot ...200819053395
experiences with population dynamics of diabrotica virgifera virgifera leconte in the swiss canton of ticino up to 2007.the western corn rootworm (wcr) diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae) is a vexing alien invasive insect pest. it occupies the attention of entomologists in most countries of europe and beyond. in spite of numerous research advances (e.g., diabrotica symposium at engelberg, switzerland 2004) its behavior is still incompletely understood and cannot be predicted for a specific growing season with any degree of certainty. nonetheless, by comparing several years in sequen ...200819226781
the western corn rootworm (diabrotica virgifera virgifera) and its first appearance in germany 2007.diabrotica v. virgifera (wcr) is one of the most successful invasive insect species and owes this success to its close association with mankind, to worldwide trade and commerce connections, and to widely practiced, monoculturally oriented production patterns which are characteristic for contemporary agriculture in several parts of the world. without a drastic change in attitudes and approaches of a globalizing agriculture, wcr will in the foreseeable future have invaded all maize growing areas. ...200819226788
acute and repeated dose (28 day) mouse oral toxicology studies with cry34ab1 and cry35ab1 bt proteins used in coleopteran resistant das-59122-7 corn.expression of the cry34ab1 and cry35ab1 proteins from bacillus thuringiensis (bt) berliner strain ps149b1 in genetically modified maize (event das-59122-7) protects the crop from damage due to feeding by diabrotica larvae including the western corn rootworm (diabrotica virgifera virgifera). as part of the safety assessment of this maize, mammalian toxicology studies were conducted with heterologously produced cry34ab1 and cry35ab1 proteins. no evidence of acute toxicity was observed in mice foll ...200919328831
susceptibility of diabrotica virgifera virgifera (coleoptera: chrysomelidae) to the entomopathogenic fungus metarhizium anisopliae when feeding on bacillus thuringiensis cry3bb1-expressing maize.genetically engineered maize producing the insecticidal protein cry3bb1 from bacillus thuringiensis (bt maize) is protected against corn rootworms (diabrotica spp.), which are serious maize pests in north america and europe. the aim of the present study was to investigate the interaction of bt maize (event mon88017) and the entomopathogenic fungus metarhizium anisopliae for controlling the western corn rootworm, diabrotica virgifera virgifera. exposure to cry3bb1 expressed in bt maize seedlings ...200919376921
impact of mon863 transgenic roots is equivalent on western corn rootworm larvae for a wide range of maize phenologies.the effects of maize, zea mays l., phenology on establishment, damage, and adult emergence of the western corn rootworm, diabrotica virgifera virgifera leconte, on mon863 transgenic maize expressing the cry3bb1 protein and its isoline was evaluated in field trials in 2002 and 2003. as expected, plant damage, western corn rootworm larval recovery, and adult emergence were significantly lower on mon863 than isoline maize. the average weight of larvae and adults recovered from mon863 and isoline ma ...200919736775
effectiveness of glues used for harmonic radar tag attachment and impact on survival and behavior of three insect pests.the ability of three cyanoacrylate glues to ensure a durable bond between the colorado potato beetle, leptinotarsa decemlineata (say), the plum curculio, conotrachelus nenuphar (herbst), or the corn rootworms (western corn rootworm, diabrotica virgifera virgifera leconte and northern corn rootworm, diabrotica longicornis smith and lawrence) and the harmonic radar tag without impact on behavior and survival was assessed as part of a study on the use of harmonic radar technology to track these ins ...200919791611
dispersal and mating behavior of diabrotica virgifera virgifera (coleoptera: chrysomelidae) in bt cornfields.understanding of the mating and dispersal behavior of the western corn rootworm, diabrotica virgifera virgifera (leconte), is essential to predicting potential resistance to bt corn technologies recently deployed to combat this pest. to quantify movement of male beetles, field studies were conducted during 2006 and 2007 in commercial bt cornfields that included the environmental protection agency-mandated 20% refuge acreage. wing traps containing a single virgin female beetle were placed along t ...200919791612
harmonic radar: assessing the impact of tag weight on walking activity of colorado potato beetle, plum curculio, and western corn rootworm.the impact of electronic dipole tags on the walking activity of three insects was determined using video tracking software. results varied within and between the three species studied. the heaviest tag mounted on the pronotum of the colorado potato beetle, leptinotarsa decemlineata (say), reduced its mean horizontal speed slightly but significantly. the mean horizontal speed of plum curculio, conotrachelus nenuphar (herbst), was significantly reduced by a light tag but not by heavier tags. the m ...201020214369
modeling evolution of diabrotica virgifera virgifera (coleoptera: chrysomelidae) to transgenic corn with two insecticidal traits.a simulation model of the population dynamics and genetics of western corn rootworm, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae), was created to evaluate the use of refuges in the management of resistance to transgenic insecticidal corn, zea mays l., expressing one or two toxin traits. hypothetical scenarios and a case study of a corn hybrid pyramided with existing toxins are simulated. in the hypothetical situations, results demonstrated that evolution is generally delaye ...201020568632
molecular evolution of glycoside hydrolase genes in the western corn rootworm (diabrotica virgifera virgifera).cellulose is an important nutritional resource for a number of insect herbivores. digestion of cellulose and other polysaccharides in plant-based diets requires several types of enzymes including a number of glycoside hydrolase (gh) families. in a previous study, we showed that a single gh45 gene is present in the midgut tissue of the western corn rootworm, diabrotica virgifera virgifera (coleoptera: chrysomelidae). however, the presence of multiple enzymes was also suggested by the lack of a si ...201424718603
carbon dioxide receptor genes and their expression profile in diabrotica virgifera virgifera.diabrotica virgifera virgifera, western corn rootworm, is one of the most devastating species in north america. d. v. virgifera neonates crawl through the soil to locate the roots on which they feed. carbon dioxide (co2) is one of the important volatile cues that attract d. v. virgifera larvae to roots.201626746870
density-dependent and density-independent mortality of the western corn rootworm: impact on dose calculations of rootworm-resistant bt corn.the percentage of viable eggs of the western corn rootworm, diabrotica virgifera virgifera leconte, which survived to the adult stage was evaluated for the effect of egg density in 2005 and 2007 in central missouri. in 2005, each plot was 2.44 by 3.05 m and contained 64 maize (corn), zea mays l., plants. in 2007, plots were 3.05 by 3.05 m and again contained 64 corn plants. seven egg densities (2,400, 1,200, 600, 300, 100, 50, and 25 viable eggs per 30.5 cm) were evaluated with four to six repli ...201020214371
evaluating western corn rootworm (coleoptera: chrysomelidae) emergence and root damage in a seed mix refuge.resistance management is essential for maintaining the efficacy and long-term durability of transgenic corn engineered to control western corn rootworm (diabrotica virgifera virgifera le conte). theoretically, a refuge can be provided by growing susceptible (refuge) plants in either a separate section of the field adjacent to resistant (transgenic) plants, or as a seed mixture. we examined the effects of varying the structure of a 10 and 20% refuge between currently approved structured refuges ( ...201020214380
microbial symbionts in insects influence down-regulation of defense genes in maize.diabrotica virgifera virgifera larvae are root-feeding insects and significant pests to maize in north america and europe. little is known regarding how plants respond to insect attack of roots, thus complicating the selection for plant defense targets. diabrotica virgifera virgifera is the most successful species in its genus and is the only diabrotica beetle harboring an almost species-wide wolbachia infection. diabrotica virgifera virgifera are infected with wolbachia and the typical gut flor ...201020596533
isolation of transcripts from diabrotica virgifera virgifera leconte responsive to the bacillus thuringiensis toxin cry3bb1.crystal (cry) proteins derived from bacillus thuringiensis (bt) have been widely used as a method of insect pest management for several decades. in recent years, a transgenic corn expressing the cry3bb1 toxin has been successfully used for protection against corn rootworm larvae (genus diabrotica). the biological action of the bt toxin in corn rootworms has not yet been clearly defined. because development of resistance to bt by corn rootworms will have huge economic and ecological costs, insigh ...201020337747
enhancing cry1ac toxicity by expression of the helicoverpa armigera cadherin fragment in bacillus thuringiensis.insect cadherin proteins localized in the midgut epithelium were identified as receptors for bacillus thuringiensis insecticidal crystal proteins (cry toxins). these cadherins facilitated toxin monomer oligomerization and mediated oligomer binding to secondary receptors. it has been reported that manduca sexta, helicoverpa armigera, anopheles gambiae and diabrotica virgifera cadherin toxin binding regions function as synergists for cry1a, cry4ba and cry3a toxicity against target insects. in the ...201020438837
relevance of traditional integrated pest management (ipm) strategies for commercial corn producers in a transgenic agroecosystem: a bygone era?the use of transgenic bt maize hybrids continues to increase significantly across the corn belt of the united states. in 2009, 59% of all maize planted in illinois was characterized as a "stacked" gene variety. this is a 40% increase since 2006. stacked hybrids typically express one cry protein for corn rootworm control and one cry protein for control of several lepidopteran pests; they also feature herbicide tolerance (to either glyphosate or glufosinate). slightly more than 50 years has passed ...201020873716
harmonic radar: efficacy at detecting and recovering insects on agricultural host plants.in pest management research, harmonic radar systems have been largely used to study insect movement across open or vegetation-poor areas because the microwave signal is attenuated by the high water content of vegetation. this study evaluated whether the efficacy of this technology is sufficient to track insects in vegetative landscapes.201121058275
antixenosis in maize reduces feeding by western corn rootworm larvae (coleoptera: chrysomelidae).sum2162 is the first known example of a naturally occurring maize, zea mays l., genotype with antixenosis (nonpreference) resistance to western corn rootworm, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae), larval feeding. behavioral responses of neonate western corn rootworm larvae were evaluated in laboratory bioassays with seven maize genotypes selected for native resistance to rootworm feeding damage. two susceptible maize genotypes and one transgenic (bacillus thuringien ...201021309225
impact of cry3bb1-expressing bt maize on adults of the western corn rootworm, diabrotica virgifera virgifera (coleoptera: chrysomelidae).genetically engineered maize producing insecticidal cry3bb1 protein from bacillus thuringiensis (bt) is protected from root damage by corn rootworm larvae. an examination was made to establish whether western corn rootworm (diabrotica virgifera virgifera) adults are affected by cry3bb1-expressing maize (mon88017) when feeding on above-ground tissue.201121360646
belowground resistance to western corn rootworm in lepidopteran-resistant maize genotypes.several maize, zea mays l., inbred lines developed from an antiguan maize population have been shown to exhibit resistance to numerous aboveground lepidopteran pests. this study shows that these genotypes are able to significantly reduce the survival of two root feeding pests, western corn rootworm, diabrotica virgifera virgifera leconte, and southern corn rootworm, diabrotica undecimpunctata howardi barber. the results also demonstrated that feeding by the aboveground herbivore fall armyworm, s ...201121404871
protease activities in the midgut of western corn rootworm (diabrotica virgifera virgifera leconte).the western corn rootworm is one of the most economically important pests in corn. one possibility for controlling this pest is the cultivation of transgenic corn expressing bacillus thuringiensis (bt) toxins, such as cry3a, cry34ab1/cry35ab1, and cry3bb1. however, widespread cultivation of the resulting bt corn may result in the development of resistant pest populations. the bt toxins are processed by proteases in the midgut of susceptible insects. thus, protease activity studies were conducted ...200919320044
containment of the western corn rootworm diabrotica v.virgifera: continued successful management 2008 in southern switzerland by monitoring and crop rotation.diabrotica virgifera virgifera leconte (col.: chrysomelidae), known as western corn rootworm (wcr) and endemic in north america, invaded europe about two decades ago. various unsuccessful attempts have been made to eradicate it from the old world. management with a variety of strategies is the option now remaining. wcr management in southern switzerland by a unique containment approach has been practiced successfully since 2003 using biotechnical means. without any chemical pesticides or gmo inp ...200920222583
lepidopteran-active variable-region sequence imparts coleopteran activity in ecry3.1ab, an engineered bacillus thuringiensis hybrid insecticidal protein.a unique, coleopteran-active protein, termed ecry3.1ab, was generated following variable-region exchange of a bacillus thuringiensis lepidopteran-active protein, cry1ab, with a cry3a region. our results support the hypothesis that this variable-region exchange is responsible for imparting strong bioactivity against the larvae of western corn rootworm (wcr) (diabrotica virgifera virgifera leconte), a pest species which is not susceptible to either parent protein sequence. this study demonstrates ...201020305020
a selective insecticidal protein from pseudomonas for controlling corn rootworms.the coleopteran insect western corn rootworm (wcr) (diabrotica virgifera virgifera leconte) is a devastating crop pest in north america and europe. although crop plants that produce bacillus thuringiensis (bt) proteins can limit insect infestation, some insect populations have evolved resistance to bt proteins. here we describe an insecticidal protein, designated ipd072aa, that is isolated from pseudomonas chlororaphis. transgenic corn plants expressing ipd072aa show protection from wcr insect i ...201627708055
assessing the risk posed to free-living soil nematodes by a genetically modified maize expressing the insecticidal cry3bb1 protein.before pest-resistant genetically modified maize can be grown commercially, the risks for soil-beneficial, non-target organisms must be determined. here, a tiered approach was used to assess the risk to free-living soil nematodes posed by maize genetically modified to express the insecticidal cry3bb1 protein (event mon88017), which confers resistance towards western corn rootworm (diabrotica virgifera; coleoptera). the toxicity of purified cry3bb1 for the nematode caenorhabditis elegans was dete ...201121511326
polymorphic microsatellite loci from northern and mexican corn rootworms (insecta: coleoptera: chrysomelidae) and cross-amplification with other diabrotica spp.the northern corn rootworm (diabrotica barberi) and mexican corn rootworm (diabrotica virgifera zeae) are significant agricultural pests. for the northern corn rootworm, and to a lesser extent, the mexican corn rootworm, high resolution molecular markers are needed. here we present 14 polymorphic microsatellite loci isolated from libraries constructed using pooled northern and mexican corn rootworm genomic dna. polymorphism in other diabrotica, including the banded cucumber beetle, southern corn ...200821585878
selection for cry3bb1 resistance in a genetically diverse population of nondiapausing western corn rootworm (coleoptera: chrysomelidae).five short-diapause laboratory lines of western corn rootworm, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae), were selected for resistance to mon863, a variety of corn genetically modified with the bacillus thuringiensis berliner (bt) transgene that expresses the cry3bb1 delta-endotoxin. three of the selected lines were developed by incremental increase in the duration of exposure to mon863 over 11 generations (moderate selected lines). two selected lines were developed from ...201121735927
bt maize and integrated pest management-a european perspective.the european corn borer (ostrinia nubilalis), the mediterranean corn borer (sesamia nonagrioides) and the western corn rootworm (diabrotica virgifera virgifera) are the main arthropod pests in european maize production. practised pest control includes chemical control, biological control and cultural control such as ploughing and crop rotation. a pest control option that is available since 1996 is maize varieties that are genetically engineered (ge) to produce insecticidal compounds. ge maize va ...201121710684
selection for resistance to mcry3a-expressing transgenic corn in western corn rootworm.to investigate the development of resistance to mcry3a, a laboratory colony of the western corn rootworm, diabrotica virgifera virgifera leconte, was established from field survivors of mcry3a-expressing (mir604) corn, zea mays l. feral adults emerging from mir604 (selected) and isoline (control) field plots were collected and returned to the laboratory. progeny of each colony was reared one generation on isoline corn and then crossed reciprocally with a nondiapausing colony. the resulting nondi ...201121735928
mortality impact of bt transgenic maize roots expressing ecry3.1ab, mcry3a, and ecry3.1ab plus mcry3a on western corn rootworm larvae in the field.mortality of the western corn rootworm, diabrotica virgifera virgifera leconte, larvae due to feeding on maize, zea mays l., expressing bacillus thuringiensis berliner (bt) was evaluated in five missouri sites in 2007, 2008, and 2009. specifically, ecry3.1ab (5307), mcry3a (mir604), and ecry3.1ab plus mcry3a proteins relative to survivorship on maize with the same genetic background without these genes (isoline maize) was evaluated. an average of 890.8 +/- 152.3 beetles emerged from isoline plot ...201122066188
Evaluation of tag entanglement as a factor in harmonic radar studies of insect dispersal.The observation of insects and other small organisms entangled in the habitat after the addition of vertical or trailing electronic tags to their body has generated concerns on the suitability of harmonic radars to track the dispersal of insects. This study compared the walking behavior of adult Colorado potato beetle (Leptinotarsa decemlineata (Say) Chrysomelidae), plum curculio (Conotrachelus nenuphar (Herbst) Curculionidae), and western corn rootworm (Diabrotica virgifera virgifera (LeConte) ...201122182617
bacillus thuringiensis cry34ab1/cry35ab1 interactions with western corn rootworm midgut membrane binding sites.bacillus thuringiensis (bt) cry34ab1/cry35ab1 are binary insecticidal proteins that are co-expressed in transgenic corn hybrids for control of western corn rootworm, diabrotica virgifera virgifera leconte. bt crystal (cry) proteins with limited potential for field-relevant cross-resistance are used in combination, along with non-transgenic corn refuges, as a strategy to delay development of resistant rootworm populations. differences in insect midgut membrane binding site interactions are one li ...201323308139
novel three-step pseudo-absence selection technique for improved species distribution modelling.pseudo-absence selection for spatial distribution models (sdms) is the subject of ongoing investigation. numerous techniques continue to be developed, and reports of their effectiveness vary. because the quality of presence and absence data is key for acceptable accuracy of correlative sdm predictions, determining an appropriate method to characterise pseudo-absences for sdm's is vital. the main methods that are currently used to generate pseudo-absence points are: 1) randomly generated pseudo-a ...201323967167
rna interference: a promising biopesticide strategy against the african sweetpotato weevil cylas brunneus.the african sweetpotato weevil cylas brunneus is one of the most devastating pests affecting the production of sweetpotatoes, an important staple food in sub-saharan africa. current available control methods against this coleopteran pest are limited. in this study, we analyzed the potential of rna interference as a novel crop protection strategy against this insect pest. first, the c. brunneus transcriptome was sequenced and rnai functionality was confirmed by successfully silencing the laccase2 ...201627941836
effects of entomopathogens on mortality of western corn rootworm (coleoptera: chrysomelidae) and fitness costs of resistance to cry3bb1 maize.fitness costs can delay pest resistance to crops that produce insecticidal toxins derived from the bacterium bacillus thuringiensis (bt), and past research has found that entomopathogens impose fitness costs of bt resistance. in addition, entomopathogens can be used for integrated pest management by providing biological control of pests. the western corn rootworm, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae), is a major pest of maize and is currently managed by planting of ...201424665720
effects of field history on corn root injury and adult abundance of northern and western corn rootworm (coleoptera: chrysomelidae).western corn rootworm, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae), and northern corn rootworm, diabrotica barberi smith & lawrence, are major pests of corn (zea mays l.). corn producing bacillus thuringiensis (bt) toxins are widely used to manage diabrotica spp.; however, bt resistance by d. v. virgifera has led to high levels of feeding injury in the field. we tested whether field history affected root injury and abundance of adult diabrotica spp. in 2013 and 2014, four ...201627498115
safety considerations derived from cry34ab1/cry35ab1 structure and function.insecticidal proteins developed for in-plant protection against crop pests undergo extensive safety testing during the product development process. safety considerations for insecticidal proteins expressed in crops follow recommended, science-based guidelines and specific studies are conducted on a case by case basis. corn events expressing bacillus thuringiensis (bt) cry34ab1 and cry35ab1 were developed to protect maize from diabrotica virgifera virgifera (western corn rootworm) feeding damage. ...201727480405
field-evolved resistance to bt maize by western corn rootworm.crops engineered to produce insecticidal toxins derived from the bacterium bacillus thuringiensis (bt) are planted on millions of hectares annually, reducing the use of conventional insecticides and suppressing pests. however, the evolution of resistance could cut short these benefits. a primary pest targeted by bt maize in the united states is the western corn rootworm diabrotica virgifera virgifera (coleoptera: chrysomelidae).201121829470
rna interference as a method for target-site screening in the western corn rootworm, diabrotica virgifera virgifera.to test the efficacy of rna interference (rnai) as a method for target-site screening in diabrotica virgifera virgifera leconte (coleptera: 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 double-stranded rna resulted in prevention of post-molt c ...021067417
patterns of gene expression in western corn rootworm (diabrotica virgifera virgifera) neonates, challenged with cry34ab1, cry35ab1 and cry34/35ab1, based on next-generation sequencing.with next generation sequencing technologies, high-throughput rna sequencing (rnaseq) was conducted to examine gene expression in neonates of diabrotica virgifera virgifera (leconte) (western corn rootworm, wcr) challenged with individual proteins of the binary bacillus thuringiensis insecticidal proteins, cry34ab1 and cry35ab1, and the combination of cry34/cry35ab1, which together are active against rootworm larvae. integrated results of three different statistical comparisons identified 114 an ...201728358336
influence of calcareous soil on cry3bb1 expression and efficacy in the field.greater than expected injury by western corn rootworm (wcr) (diabrotica virgifera virgifera leconte) to cry3bb1 expressing maize hybrids (zea mays l.) has been reported in southwestern nebraska. affected areas of some fields are often associated with high ph calcareous soils where maize growth is poor and iron chlorosis is common. as part of a comprehensive study to understand potential causes of unexpected injury, experiments were conducted during 2013 and 2014 to ascertain whether the calcareo ...201728326506
multiple assays indicate varying levels of cross resistance in cry3bb1-selected field populations of the western corn rootworm to mcry3a, ecry3.1ab, and cry34/35ab1.minnesota populations of diabrotica virgifera virgifera leconte, the western corn rootworm, surviving cry3bb1-expressing corn in the field and western corn rootworm populations assumed to be susceptible to all bt proteins were evaluated for susceptibility to cry3bb1, mcry3a, ecry3.1ab, and cry34/35ab1 in diet assays and three different plant-based assays. rootworm populations originating from cry3bb1 fields and that consistently experienced greater than expected damage had increased survival and ...201627106225
evaluation of corn hybrids expressing cry34ab1/cry35ab1 and cry3bbl against the western corn rootworm (coleoptera: chrysomelidae).studies were conducted across nine u.s. states, over 5 yr, to characterize the efficacy of transgenic corn (zea mays l.) hybrids producing insecticidal proteins derived from bacillus thuringiensis (bt) for control of western corn rootworm, diabrotica virgifera virgifera le conte. hybrids tested had the same genetic background, contained one of two single events (das-59122-7 expressing cry34ab1/cry35ab1 or mon 88017 expressing cry3bb1) or a pyramid consisting of both rootworm-active events (smart ...201323786070
evaluation of corn hybrids expressing cry1f, cry1a.105, cry2ab2, cry34ab1/cry35ab1, and cry3bb1 against southern united states insect pests.studies were conducted across the southern united states to characterize the efficacy of multiple bacillus thuringiensis (bt) events in a field corn, zea mays l., hybrid for control of common lepidopteran and coleopteran pests. cry1f protein in event tc1507 and cry1a.105 + cry2ab2 proteins in event mon 89034 were evaluated against pests infesting corn on above-ground plant tissue including foliage, stalks, and ears. cry34ab1/cry35ab1 proteins in event das-59122-7 and cry3bb1 in event mon 88017 w ...201223156183
ipm use with the deployment of a non-high dose bt pyramid and mitigation of resistance for western corn rootworm (diabrotica virgifera virgifera).recent detection of western corn rootworm resistance to bt (bacillus thuringiensis) corn prompted recommendations for the use of integrated pest management (ipm) with planting refuges to prolong the durability of bt technologies. we conducted a simulation experiment exploring the effectiveness of various ipm tools at extending durability of pyramided bt traits. results indicate that some ipm practices have greater merits than others. crop rotation was the most effective strategy, followed by inc ...201627018423
greenhouse-selected resistance to cry3bb1-producing corn in three western corn rootworm populations.transgenic corn producing the bacillus thuringiensis (bt) toxin cry3bb1 has been useful for controlling western corn rootworm, diabrotica virgifera virgifera leconte, one of the most economically important crop pests in the united states. however, rapid evolution of resistance by this beetle to bt corn producing cry3bb1 has been reported previously from the laboratory, greenhouse, and field. here we selected in the greenhouse for resistance to cry3bb1 corn in three colonies of wcr derived from k ...201223284656
effects of cry34/35ab1 corn on the survival and development of western corn rootworm, diabrotica virgifera virgifera.the western corn rootworm, diabrotica virgifera virgifera leconte, is a major agricultural pest that is managed with transgenic corn, zea mays l., expressing genes from bacillus thuringiensis berliner (bt). the effects of bt corn producing cry34/35ab1 (event das-59122-7) and entomopathogens on the survival and development of larval d. v. virgifera were examined in laboratory, field and greenhouse experiments.201323109348
adaptation by western corn rootworm (coleoptera: chrysomelidae) to bt maize: inheritance, fitness costs, and feeding preference.we examined inheritance of resistance, feeding behavior, and fitness costs for a laboratory-selected strain of western corn rootworm, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae), with resistance to maize (zea maize l.) producing the bacillus thuringiensis berliner (bt) toxin cry3bb1. the resistant strain developed faster and had increased survival on bt maize relative to a susceptible strain. results from reciprocal crosses of the resistant and susceptible strains indicate ...201222928323
development of a co2 -releasing coformulation based on starch, saccharomyces cerevisiae and beauveria bassiana attractive towards western corn rootworm larvae.co2 is known as an attractant for many soil-dwelling pests. to implement an attract-and-kill strategy for soil pest control, co2 -emitting formulations need to be developed. the aim of the present work was to develop a slow-release bead system in order to bridge the gap between application and hatching of western corn rootworm larvae.201626834068
entomopathogenic fungi in cornfields and their potential to manage larval western corn rootworm diabrotica virgifera virgifera.entomopathogenic ascomycete fungi are ubiquitous in soil and on phylloplanes, and are important natural enemies of many soil-borne arthropods including larval western corn rootworm, diabrotica virgifera virgifera, which is a major pest of corn. we measured the prevalence of beauveria bassiana and metarhizium anisopliae sensu lato in ten cornfields in iowa, usa by baiting with larval insects. b. bassiana and m. anisopliae s.l. were present in 60% ± 6.3% and 55% ± 6.4% of soil samples, respectivel ...201324120889
western corn rootworm and bt maize: challenges of pest resistance in the field.crops genetically engineered to produce insecticidal toxins from the bacterium bacillus thuringiensis (bt) manage many key insect pests while reducing the use of conventional insecticides. one of the primary pests targeted by bt maize in the united states is the western corn rootworm, diabrotica virgifera virgifera leconte. beginning in 2009, populations of western corn rootworm were identified in iowa, usa that imposed severe root injury to cry3bb1 maize. subsequent laboratory bioassays reveale ...201422688688
a multi-scale, landscape approach to predicting insect populations in agroecosystems.landscape composition affects ecosystems services, including agricultural pest management. however, relationships between land use and agricultural insects are not well understood, and many complexities remain to be explored. here we examine whether nonagricultural landscapes can directly suppress agricultural pests, how multiple spatial scales of land use concurrently affect insect populations, and the relationships between regional land use and insect populations. we tracked densities of three ...201121830718
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