| 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 ... | 2014 | 22688688 |
| 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 |
| spatial prediction of corn rootworm (coleoptera: chrysomelidae) adult emergence in iowa cornfields. | the most common management options for corn rootworms are rotating corn with nonhost crops, planting genetically engineered corn resistant to corn rootworms (e.g., bacillus thuringiensis [bt] corn), and treating with a soil insecticide at planting time. because these control tactics are preventive, the decision to apply controls has been made without any knowledge of rootworm density and spatial distribution. this study was conducted to predict the spatial distribution of adult emergence and to ... | 2005 | 15765673 |
| occurrence of maize detritus and a transgenic insecticidal protein (cry1ab) within the stream network of an agricultural landscape. | widespread planting of maize throughout the agricultural midwest may result in detritus entering adjacent stream ecosystems, and 63% of the 2009 us maize crop was genetically modified to express insecticidal cry proteins derived from bacillus thuringiensis. six months after harvest, we conducted a synoptic survey of 217 stream sites in indiana to determine the extent of maize detritus and presence of cry1ab protein in the stream network. we found that 86% of stream sites contained maize leaves, ... | 2010 | 20876106 |
| areawide suppression of european corn borer with bt maize reaps savings to non-bt maize growers. | transgenic maize engineered to express insecticidal proteins from the bacterium bacillus thuringiensis (bt) has become widely adopted in u.s. agriculture. in 2009, bt maize was planted on more than 22.2 million hectares, constituting 63% of the u.s. crop. using statistical analysis of per capita growth rate estimates, we found that areawide suppression of the primary pest ostrinia nubilalis (european corn borer) is associated with bt maize use. cumulative benefits over 14 years are an estimated ... | 2010 | 20929774 |
| assessing the impact of cry1ab-expressing corn pollen on monarch butterfly larvae in field studies. | survival and growth of monarch larvae, danaus plexippus (l.), after exposure to either cry1ab-expressing pollen from three bacillus thuringiensis (bt) corn (zea mays l.) events differing in toxin expression or to the insecticide, lambda-cyhalothrin, were examined in field studies. first instars exposed to low doses ( approximately 22 grains per cm(2)) of event-176 pollen gained 18% less weight than those exposed to bt11 or mon810 pollen after a 5-day exposure period. larvae exposed to 67 pollen ... | 2001 | 11559839 |
| feeding behavior of neonate ostrinia nubilalis (lepidoptera: crambidae) on cry1ab bt corn: implications for resistance management. | the european corn borer, ostrinia nubilalis (h++bner) (lepidoptera: crambidae), is an economically important insect pest of corn, zea mays l., in the united states and canada. the development of genetically modified corn expressing genes derived from bacillus thuringiensis (bt) that encodes insecticidal crystalline (cry) proteins has proven to be effective in controlling this insect. to assess the feeding behavior of neonate o. nubilalis on bt corn, we examined differences in feeding behavior, b ... | 2011 | 21735897 |
| frequency of resistance to bacillus thuringiensis toxin cry1ab in an iowa population of european corn borer (lepidoptera: crambidae). | the refuge plus high-dose strategy for resistance management assumes that the frequency of resistance alleles is low. we used an f2 screen to estimate the frequency of resistance to transgenic corn that produces bacillus thuringiensis berliner cry1ab toxin (bt corn) in an iowa population of european corn borer, ostrinia nubilalis (hübner). we also proposed a modification to the statistical analysis of the f2 screen that extends its application for nonuniform prior distributions and for repeated ... | 2000 | 14658507 |
| economic analysis of planting dates to manage european corn borer (lepidoptera: crambidae) with bt corn. | planting dates of transgenic bacillus thuringiensis berliner (bt) corn were adjusted to determine the utility in managing european corn borer, ostrinia nubilalis (hübner). transgenic bt (events 176 and bt11) corn and non-bt corn were planted at three different times to use the early- and late- planted corn as a potential trap crop for ovipositing european corn borer moths. grain moisture and yields were recorded to determine the economic benefits of bt corn planted on the different dates, based ... | 2003 | 12852640 |
| efficacy of bacillus sphaericus and bacillus thuringiensis var. israelensis for control of culex pipiens and floodwater aedes larvae in iowa. | granular and flowable concentrate formulations of bacillus thuringiensis var. israelensis provided a 90-100% reduction in aedes vexans and culex spp. larvae in natural larval habitats. a briquet formulation of b. thuringiensis was less effective, providing a 12-76% reduction. no residual activity occurred in sites treated with b. thuringiensis. granular formulations of bacillus sphaericus (2.78-8.42 kg/ha) caused a 100% reduction in culex pipiens larvae in natural sites and artificial pools. bac ... | 1987 | 3504943 |