Evaluating Western Corn Rootworm (Coleoptera: Chrysomelidae) Emergence and Root Damage in a Seed Mix Refuge

Murphy, Alexzandra F.; Ginzel, Matthew D.; Krupke, Christian H.

doi:10.1603/ec09156

Cited by 49 publications

(72 citation statements)

References 40 publications

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“…3), consistent with Þeld data from other studies (Storer et al 2006, Murphy et al 2010, Hibbard et al 2011. Western corn rootworm is protandrous, with females emerging later than males (Branson 1987).…”

Section: Discussionsupporting

confidence: 88%

Interactions Among Bt Maize, Entomopathogens, and Rootworm Species (Coleoptera: Chrysomelidae) in the Field: Effects on Survival, Yield, and Root Injury

2013

jnl. econ. entom.

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A 2 yr field study was conducted to determine how a blend of entomopathogens interacted with Bt maize to affect mortality of Diabrotica spp. (Coleoptera: Chrysomelidae), root injury to maize (Zea maize L.) and yield. The blend of entomopathogens included two entomopathogenic nematodes, Steinernema carpocapsae Weiser and Heterorhabditis bacteriophora Poinar, and one entomopathogenic fungus, Metarhizium brunneum(Metschnikoff) Sorokin. Bt maize (event DAS59122-7, which produces Bt toxin Cry34/35Ab1) decreased root injury and survival of western corn rootworm (Diabrotica virgifera virgifera LeConte) and northern corn rootworm (Diabrotica barberi Smith & Lawrence) but did not affect yield. During year 1 of the study, when rootworm abundance was high, entomopathogens in combination with Bt maize led to a significant reduction in root injury. In year 2 of the study, when rootworm abundance was lower, entomopathogens significantly decreased injury to non-Bt maize roots, but had no effect on Bt maize roots. Yield was significantly increased by the addition of entomopathogens to the soil. Entomopathogens did not decrease survival of corn rootworm species. The results suggest that soil-borne entomopathogens can complement Bt maize by protecting roots from feeding injury from corn rootworm when pest abundance is high, and can decrease root injury to non-Bt maize when rootworm abundance is low. In addition, this study also showed that the addition of entomopathogens to soil contributed to an overall increase in yield. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. ABSTRACT A 2 yr Þeld study was conducted to determine how a blend of entomopathogens interacted with Bt maize to affect mortality of Diabrotica spp. (Coleoptera: Chrysomelidae), root injury to maize (Zea maize L.) and yield. The blend of entomopathogens included two entomopathogenic nematodes, Steinernema carpocapsae Weiser and Heterorhabditis bacteriophora Poinar, and one entomopathogenic fungus, Metarhizium brunneum (Metschnikoff) Sorokin. Bt maize (event DAS-59122Ð7, which produces Bt toxin Cry34/35Ab1) decreased root injury and survival of western corn rootworm (Diabrotica virgifera virgifera LeConte) and northern corn rootworm (Diabrotica barberi Smith & Lawrence) but did not affect yield. During year 1 of the study, when rootworm abundance was high, entomopathogens in combination with Bt maize led to a signiÞcant reduction in root injury.In year 2 of the study, when rootworm abundance was lower, entomopathogens signiÞcantly decreased injury to non-Bt maize roots, but had no effect on Bt maize roots. Yield was signiÞcantly increased by the addition of entomopathogens to the soil. Entomopathogens did not decrease survival of corn rootworm species. The results suggest that soil-borne entomopathogens can complement Bt maize by protecting roots from feeding injury from corn rootworm when pest abundance is high, and can decrease r...

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Section: Discussionsupporting

confidence: 88%

Interactions Among Bt Maize, Entomopathogens, and Rootworm Species (Coleoptera: Chrysomelidae) in the Field: Effects on Survival, Yield, and Root Injury

2013

jnl. econ. entom.

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“…It is unclear whether the relative proportion of insects that emerged from Bt and refuge plants in the integrated refuge treatments differed from those in pure stands because we did not measure emergence from individual plants. Murphy et al (2010) found that the proportion of beetles emerging from refuge plants was signiÞcantly less in an integrated refuge than in a pure stand refuge; however, the proportion that emerged from Bt plants was greater. This Þnding is similar to a Þnding by Zukoff et al (2012), who observed that signiÞcantly more western corn rootworm beetles could emerged from Bt maize plants (producing both Cry34/35Ab1 and Cry3Bb1) when these plants were surrounded by refuge plants on both sides as compared with Bt plants surrounded by Bt plants, or refuge plants surrounded by refuge plants.…”

Section: Discussionmentioning

confidence: 90%

“…Adult emergence of western corn rootworm on pure stands of Bt maize is generally later than on pure stands of non-Bt maize (Storer et al 2006, Binning et al 2010. Murphy et al (2010) measured time of emergence for western corn rootworm from Bt maize plants (producing Cry3Bb1) and refuge plants in Þeld plots planted as integrated refuges, block refuges, and strip refuges, and found that insects from refuge plants emerged more synchronously with insects from Bt plants for integrated refuges compared with blocks. Although we did not measure emergence timing from individual refuge plants in our integrated refuge treatments, our results also support more synchronous emergence of males and females in integrated refuges compared with pure stand refuge maize (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…To date, few studies have examined the effects of integrated refuge on western corn rootworm survival and life history traits in the Þeld (Murphy et al 2010(Murphy et al , 2011. Results from simulation models suggest that integrated refuge can delay Bt resistance by corn rootworm longer than block refuges (Pan et al 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Few Þeld studies have examined Þtness of western corn rootworm in a block vs. integrated refuge, or effects on susceptibility to Bt maize in the next generation (but see Hibbard et al 2010a;Murphy et al 2010Murphy et al , 2011Zukoff et al 2012). In this study, survival and Þtness of western corn rootworm adults were measured after exposure in the Þeld to pure stands of Bt maize (event 59122), pure stands of refuge (non-Bt maize), and an integrated refuge.…”

Section: Department Of Agricultureðeconomic Research Service [Usdaðermentioning

confidence: 99%

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Applying an Integrated Refuge to Manage Western Corn Rootworm (Coleoptera: Chrysomelidae): Effects on Survival, Fitness, and Selection Pressure

et al. 2013

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The refuge strategy can delay resistance of insect pests to transgenic maize producing toxins from Bacillus thuringiensis (Bt). This is important for the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), because of its history of adaptation to several management practices. A 2-yr study across four locations was conducted to measure the effects of integrated refuge (i.e., blended refuge) on western corn rootworm survival to adulthood, fitness characteristics, and susceptibility to Bt maize in the subsequent generation. The treatments tested in this study were as follows: a pure stand of Bt maize (event DAS-59122-7, which produces Bt toxins Cry34Ab1/Cry35Ab1), a pure stand of refuge (non-Bt maize), and two variations on an integrated refuge consisting of 94.4% Bt maize and 5.6% non-Bt maize. Within the two integrated refuge treatments, refuge seeds received a neonicotinoid insecticidal seed treatment of either 1.25 mg clothianidin per kernel or 0.25 mg thiamethoxam per kernel. Insects in the pure stand refuge treatment had greater survival to adulthood and earlier emergence than in all other treatments. Although fecundity, longevity, and head capsule width were reduced in treatments containing Bt maize for some site by year combinations, Bt maize did not have a significant effect on these factors when testing data across all sites and years. We found no differences in susceptibility of larval progeny to Bt maize in bioassays using progeny of adults collected from the four treatments.

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Bt Resistance Monitoring in European Corn Borers and Western Corn Rootworms

Siegfried

Spencer

2012

Plant Gene Containment

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Evaluating Western Corn Rootworm (Coleoptera: Chrysomelidae) Emergence and Root Damage in a Seed Mix Refuge

Cited by 49 publications

References 40 publications

Interactions Among Bt Maize, Entomopathogens, and Rootworm Species (Coleoptera: Chrysomelidae) in the Field: Effects on Survival, Yield, and Root Injury

Interactions Among Bt Maize, Entomopathogens, and Rootworm Species (Coleoptera: Chrysomelidae) in the Field: Effects on Survival, Yield, and Root Injury

Applying an Integrated Refuge to Manage Western Corn Rootworm (Coleoptera: Chrysomelidae): Effects on Survival, Fitness, and Selection Pressure

Bt Resistance Monitoring in European Corn Borers and Western Corn Rootworms

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