| 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 ... | 2003 | 14977111 |
| 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 ... | 2004 | 15041015 |
| 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 ... | 2004 | 15154452 |
| 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 ... | 2005 | 16156562 |
| 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 ... | 2002 | 12076012 |
| 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 ... | 2002 | 11886775 |
| 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 ... | 2000 | 10902309 |
| 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 ... | 2002 | 11872461 |
| 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 ... | 2000 | 11142317 |
| 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 ... | 2001 | 11433280 |
| 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 ... | 2005 | 16156586 |
| an in-gel assay of a recombinant western corn rootworm (diabrotica virgifera virgifera) cysteine proteinase expressed in yeast. | | 2000 | 10860514 |
| 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 ... | 1999 | 10620046 |
| 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 ... | 1997 | 9326628 |
| 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 ... | 2005 | 15811999 |
| 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 ... | 2005 | 16022329 |
| 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 ... | 2004 | 15154499 |
| 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 ... | 2004 | 15379574 |
| first report of the western corn rootworm diabrotica virgifera in belgium. | | 2004 | 15759426 |
| 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 ... | 2004 | 15294828 |
| 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 ... | 2005 | 16334339 |
| 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 ... | 2003 | 15149097 |
| 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 ... | 2006 | 16489451 |
| 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 ... | 2005 | 16628903 |
| 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 ... | 2003 | 15149095 |
| 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 ... | 2003 | 14582981 |
| 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 ... | 2003 | 15149096 |
| 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 ... | 2003 | 15149091 |
| 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 ... | 2009 | 19801487 |
| 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 ... | 2006 | 16813304 |
| 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 ... | 2006 | 16813332 |
| 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 ... | 2006 | 17385500 |
| 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 ... | 2006 | 17385526 |
| 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 ... | 2006 | 16937696 |
| 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 ... | 2008 | 18705889 |
| 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 ... | 2007 | 17725800 |
| 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 ... | 2007 | 17982443 |
| 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 ... | 2007 | 17467005 |
| 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 ... | 2008 | 19053395 |
| 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 ... | 2008 | 19047626 |
| 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 ... | 2008 | 19226781 |
| 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. ... | 2008 | 19226788 |
| 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 ... | 2009 | 19320044 |
| 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 ... | 2009 | 19328831 |
| 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 ... | 2009 | 19329664 |
| 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 ... | 2009 | 19376921 |
| 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 ... | 2009 | 19791611 |
| 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 ... | 2009 | 19791612 |
| 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 ( ... | 2010 | 20214380 |
| 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 ... | 2010 | 20214369 |
| 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 ... | 2010 | 20214371 |
| 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 ... | 2010 | 20305020 |
| 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 ... | 2009 | 20222583 |
| 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 ... | 2014 | 24718603 |
| 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 ... | 2010 | 20337747 |
| 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 ... | 2007 | 17598539 |
| 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 ... | 2010 | 20873716 |
| 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. | 2016 | 26746870 |
| 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 ... | 2007 | 17598525 |
| 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 ... | 2010 | 20857753 |
| 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. | 2011 | 21058275 |
| 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 ... | 2009 | 19736775 |
| 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 ... | 2007 | 17461083 |
| 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. | 2011 | 21360646 |
| 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 ... | 2011 | 21404871 |
| 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 ... | 2011 | 21511326 |
| 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 ... | 2011 | 21735927 |
| 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 ... | 2011 | 21830718 |
| 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 ... | 2011 | 21735928 |
| 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 ... | 2011 | 22066188 |
| 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 ... | 2004 | 15279266 |
| 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 ... | 2011 | 21710684 |
| structural and biophysical characterization of bacillus thuringiensis insecticidal proteins cry34ab1 and cry35ab1. | bacillus thuringiensis strains are well known for the production of insecticidal proteins upon sporulation and these proteins are deposited in parasporal crystalline inclusions. the majority of these insect-specific toxins exhibit three domains in the mature toxin sequence. however, other cry toxins are structurally and evolutionarily unrelated to this three-domain family and little is known of their three dimensional structures, limiting our understanding of their mechanisms of action and our a ... | 2014 | 25390338 |
| 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). | 2011 | 21829470 |
| 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) ... | 2011 | 22182617 |
| 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 ... | 2013 | 23308139 |
| 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 ... | 2013 | 23967167 |
| 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 ... | 2010 | 20438837 |
| 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 ... | 2016 | 27941836 |
| 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 ... | 2010 | 20568632 |
| 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 ... | 2010 | 20596533 |
| 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 ... | 0 | 21067417 |
| 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 ... | 2017 | 28326506 |
| 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. ... | 2017 | 27480405 |
| 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 ... | 2016 | 27708055 |
| 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 ... | 2016 | 27498115 |
| cry3bb1-resistant western corn rootworm, diabrotica virgifera virgifera (leconte) does not exhibit cross-resistance to dvsnf7 dsrna. | there is a continuing need to express new insect control compounds in transgenic maize against western corn rootworm, diabrotica virgifera virgifera (leconte) (wcr). in this study three experiments were conducted to determine cross-resistance between the new insecticidal dvsnf7 dsrna, and bacillus thuringiensis (bt) cry3bb1; used to control wcr since 2003, with field-evolved resistance being reported. laboratory susceptible and cry3bb1-resistant wcr were evaluated against dvsnf7 dsrna in larval ... | 2017 | 28060922 |
| broad-spectrum resistance to bacillus thuringiensis toxins by western corn rootworm (diabrotica virgifera virgifera). | the evolution of resistance and cross-resistance threaten the sustainability of genetically engineered crops that produce insecticidal toxins derived from the bacterium bacillus thuringiensis (bt). western corn rootworm, diabrotica virgifera virgifera leconte, is a serious pest of maize and has been managed with bt maize since 2003. we conducted laboratory bioassays with maize hybrids producing bt toxins cry3bb1, mcry3a, ecry3.1ab, and cry34/35ab1, which represent all commercialized bt toxins fo ... | 2016 | 27297953 |
| field-based assessment of resistance to bt corn by western corn rootworm (coleoptera: chrysomelidae). | western corn rootworm, diabrotica virgifera virgifera leconte, is a serious pest of corn and is managed with corn that produces insecticidal toxins derived from the bacterium bacillus thuringiensis (bt). beginning in 2009, resistance to cry3bb1 corn, and severe injury to cry3bb1 corn in the field, was observed in iowa. however, few data exist on how cry3bb1-resistant western corn rootworm interact with various management practices in the field. using a field experiment, we measured adult emergen ... | 2016 | 27122498 |
| 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 ... | 2016 | 27106225 |
| 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 ... | 2016 | 27018423 |
| western corn rootworm (coleoptera: chrysomelidae) larval movement in ecry3.1ab+mcry3a seed blend scenarios. | corn fields planted with plant-incorporated bacillus thuringiensis (bt) proteins must have a portion of the field planted with non-bt, isoline, plants that serve as a refuge for susceptible insects. in the corn belt, refuge seeds are now blended in the bag with bt seeds for corn hybrids containing two or more toxins targeted toward the western corn rootworm, diabrotica virgifera virgifera leconte. syngenta's corn hybrid, agrisure duracade, containing the ecry3.1ab (event 5307) and mcry3a (event ... | 2016 | 27190042 |
| rnai induced knockdown of a cadherin-like protein (ef531715) does not affect toxicity of cry34/35ab1 or cry3aa to diabrotica virgifera virgifera larvae (coleoptera: chrysomelidae). | the western corn rootworm (wcr), diabrotica virgifera virgifera leconte, is an important maize pest throughout most of the u.s. corn belt. bacillus thuringiensis (bt) insecticidal proteins including modified cry3aa and cry34/35ab1 have been expressed in transgenic maize to protect against wcr feeding damage. to date, there is limited information regarding the wcr midgut target sites for these proteins. in this study, we examined whether a cadherin-like gene from diabrotica virgifera virgifera (d ... | 2016 | 27334721 |
| evaluation of potential fitness costs associated with ecry3.1ab resistance in diabrotica virgifera virgifera (coleoptera: chrysomelidae). | both an ecry3.1ab-selected and paired control western corn rootworm, diabrotica virgifera virgifera leconte, colony were tested for adult longevity, egg oviposition, egg viability, and larval development in order to evaluate the potential fitness costs associated with ecry3.1ab resistance. adult longevity experiments were conducted by pairing virgin males and females together in plastic boxes supplied with food, water, and ovipositional medium and observed for survival time. eggs were also colle ... | 2016 | 27151470 |
| mating success, longevity, and fertility of diabrotica virgifera virgifera leconte (chrysomelidae: coleoptera) in relation to body size and cry3bb1-resistant and cry3bb1-susceptible genotypes. | insect resistance to population control methodologies is a widespread problem. the development of effective resistance management programs is often dependent on detailed knowledge regarding the biology of individual species and changes in that biology associated with resistance evolution. this study examined the reproductive behavior and biology of western corn rootworm beetles of known body size from lines resistant and susceptible to the cry3bb1 protein toxin expressed in transgenic bacillus t ... | 2015 | 26569315 |
| inheritance and fitness costs of resistance to cry3bb1 corn by western corn rootworm (coleoptera: chrysomelidae). | transgenic crops that produce insecticidal toxins derived from the bacterium bacillus thuringiensis (bt) are widely planted to manage pest insects. one of the primary pests targeted by bt corn in the united states is western corn rootworm, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae). cry3bb1 corn for management of western corn rootworm was commercialized in 2003, and beginning in 2009, populations of western corn rootworm with field-evolved resistance to cry3bb1 corn were ... | 2015 | 26453731 |
| susceptibility of nebraska western corn rootworm (coleoptera: chrysomelidae) populations to bt corn events. | transgenic plants have been widely adopted by growers to manage the western corn rootworm, diabrotica virgifera virgifera leconte, in field corn. because of reduced efficacy in some nebraska fields after repeated use of cry3bb1-expressing hybrids, single plant bioassays were conducted in 2012 and 2013 to characterize the susceptibility of western corn rootworm populations to the rootworm-active proteins cry3bb1, mcry3a, and cry34/35ab1. results demonstrate that there are heritable differences in ... | 2015 | 26470186 |
| effects of pyramided bt corn and blended refuges on western corn rootworm and northern corn rootworm (coleoptera: chrysomelidae). | the western corn rootworm, diabrotica virgifera virgifera leconte, and the northern corn rootworm, diabrotica barberi smith & lawrence (coleoptera: chrysomelidae), are major pests of corn (zea mays l). several transgenic corn events producing insecticidal toxins derived from the bacterium bacillus thuringiensis (bt) kill corn rootworm larvae and reduce injury to corn roots. however, planting of bt corn imposes selection on rootworm populations to evolve bt resistance. the refuge strategy and pyr ... | 2015 | 26470183 |
| emergence and abundance of western corn rootworm (coleoptera: chrysomelidae) in bt cornfields with structured and seed blend refuges. | to slow evolution of western corn rootworm (diabrotica virgifera virgifera leconte) resistance to bt (bacillus thuringiensis berliner) corn hybrids, non-bt "refuges" must be planted within or adjacent to bt cornfields, allowing susceptible insects to develop without exposure to bt toxins. bt-susceptible adults from refuges are expected to find and mate with resistant adults that have emerged from bt corn, reducing the likelihood that bt-resistant offspring are produced. the spatial and temporal ... | 2015 | 26470111 |
| 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 ... | 2010 | 21309225 |