Field and Laboratory Studies of Resistance to Bt Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae)

2019 ◽  
Vol 112 (5) ◽  
pp. 2324-2334 ◽  
Author(s):  
Ram B Shrestha ◽  
Aaron J Gassmann
Keyword(s):  
Field Experiments ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Cross Resistance ◽  
Corn Rootworm ◽  
Insecticidal Toxin ◽  
Susceptible Population ◽  
History Of ◽  
Bacterium Bacillus

Abstract Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), has developed resistance to transgenic corn that produces the insecticidal toxin Cry3Bb1 derived from the bacterium Bacillus thuringiensis (Bacillales: Bacillaceae) (Bt), with cross-resistance extending to corn with Bt toxins mCry3A and eCry3.1Ab. Additionally, some populations of western corn rootworm have evolved resistance to Cry34/35Ab1 corn. We conducted a 2-yr field and laboratory study that included three field locations: 1) Bt-susceptible population, 2) field with a recent history of Cry3Bb1 resistance, and 3) field with a long-term history of Cry3Bb1 resistance. The population with recently evolved Cry3Bb1 resistance showed resistance to Cry3Bb1 corn in both laboratory bioassays and field evaluations; by contrast, the population with a long-term history of Cry3Bb1 resistance showed resistance, in both laboratory and field experiments to Cry3Bb1 corn and corn with a pyramid of mCry3A plus eCry3.1Ab corn. Field-based evaluations also showed that the field population with a long-term history of Cry3Bb1 resistance imposed higher root injury to Cry3Bb1 corn and the pyramid of mCry3A plus eCry3.1Ab compared with the susceptible control. The results of this study are discussed in the context of developing strategies to manage western corn rootworm in areas where populations have evolved resistance to Cry3Bb1 corn.

scholarly journals Cry75Aa (Mpp75Aa) Insecticidal Proteins for Controlling the Western Corn Rootworm, Diabrotica virgifera virgifera, (Coleoptera: Chrysomelidae), Isolated from the Insect Pathogenic Bacteria Brevibacillus laterosporus.

2020 ◽  
Author(s):  
David Bowen ◽  
Yong Yin ◽  
Stanislaw Flasinski ◽  
Catherine Chay ◽  
Gregory Bean ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Pathogenic Bacteria ◽  
Insect Pests ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Cross Resistance ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Insecticidal Proteins ◽  
Brevibacillus Laterosporus

This study describes three closely related proteins, cloned from Brevibacillus laterosporus strains, that are lethal upon feeding to Diabrotica virgifera virgifera LeConte, the western corn rootworm (WCR). Mpp75Aa1, Mpp75Aa2 and Mpp75Aa3 were toxic to WCR larvae when fed purified protein. Transgenic plants expressing each mMpp75Aa protein were protected from feeding damage and showed significant reduction in adult emergence from infested plants by both susceptible and Cry3Bb1 and Cry34Ab1/Cry35Ab1-resistant WCR. These results demonstrate that proteins from B. laterosporus are as efficacious as the well-known Bacillus thuringiensis (Bt) insecticidal proteins in controlling major insect pests such as WCR. The deployment of transgenic maize expressing mMpp75Aa along with other active molecules lacking cross-resistance have the potential to be a useful tool for control of WCR populations resistant to current Bt traits. IMPORTANCE Insects feeding on roots of crops can damage the plant roots resulting in yield loss due to poor water and nutrient uptake and plant lodging. In maize the western corn rootworm (WCR) can cause severe damage to the roots resulting in significant economic loss for farmers. Genetically modified (GM) expressing Bacillus thuringiensis (Bt) insect control proteins, has provided a solution for control of these pests. In recent years populations of WCR resistant to the Bt proteins in commercial GM maize have emerged. There is a need to develop new insecticidal traits for the control of WCR populations resistant to current commercial traits. New proteins with commercial level efficacy on WCR from sources other than Bt are becoming more critical. The Mpp75Aa proteins, from B. laterosporus, when expressed in maize, are efficacious against the resistant populations of WCR and have the potential to provide solutions for control of resistant WCR.

scholarly journals Comparing Populations of Western Corn Rootworm (Coleoptera: Chrysomelidae) in Regions With and Without a History of Injury to Cry3 Corn

2020 ◽  
Vol 113 (4) ◽  
pp. 1839-1849
Author(s):  
Coy R St. Clair ◽  
Graham P Head ◽  
Aaron J Gassmann
Keyword(s):  
Management Strategies ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Management Tool ◽  
Bt Corn ◽  
Corn Rootworm ◽  
Root Injury ◽  
Important Pest ◽  
Bacterium Bacillus ◽  
Management Tactics

Abstract Transgenic corn expressing insecticidal proteins derived from the bacterium Bacillus thuringiensis (Bt) is an important pest management tool. Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a key pest of corn in the midwestern United States that has developed field-evolved resistance to all available Bt traits. The first Bt trait to be commercialized for management of rootworm was Cry3Bb1 in 2003, and field-evolved resistance appeared in 2009. In this study, we examined fields in counties where greater-than-expected injury to Cry3 (Cry3Bb1 or mCry3A) corn roots (>1 node) had previously been reported (problem counties) and counties where injury had not been reported (non-problem counties). Four to eight fields were sampled per county in 2015, 2016, and 2017 to quantify rootworm abundance, root injury, Cry3Bb1resistance, and rootworm management strategies. Rootworm abundance, root injury, and resistance to Cry3Bb1 did not differ between county types. Management tactics differed between county types, with problem counties growing more corn, using more soil insecticide, and growing more Cry34/35Ab1 corn. Additionally, a comparison of root injury to Bt and non-Bt corn within fields indicated that farmers derived an economic benefit from planting Bt corn to manage corn rootworm. Our results suggest that rootworm populations are similar between problem and non-problem counties in Iowa due to similar levels of selection pressure on Cry3 corn, but problem county fields have applied more management tactics due to previous rootworm issues in the area.

scholarly journals The Use of Insecticides to Manage the Western Corn Rootworm, Diabrotica virgifera virgifera, LeConte: History, Field-Evolved Resistance, and Associated Mechanisms

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 112 ◽  
Author(s):  
Lance J. Meinke ◽  
Dariane Souza ◽  
Blair D. Siegfried
Keyword(s):  
Diabrotica Virgifera Virgifera ◽  
The United States ◽  
Western Corn Rootworm ◽  
Cross Resistance ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Mechanisms Of Resistance ◽  
Pyrethroid Insecticides ◽  
Diabrotica Virgifera Virgifera Leconte ◽  
Over Time

The western corn rootworm, Diabrotica virgifera virgifera LeConte (Dvv) is a significant insect pest of maize in the United States (U.S.). This paper reviews the history of insecticide use in Dvv management programs, Dvv adaptation to insecticides, i.e., field-evolved resistance and associated mechanisms of resistance, plus the current role of insecticides in the transgenic era. In the western U.S. Corn Belt where continuous maize is commonly grown in large irrigated monocultures, broadcast-applied soil or foliar insecticides have been extensively used over time to manage annual densities of Dvv and other secondary insect pests. This has contributed to the sequential occurrence of Dvv resistance evolution to cyclodiene, organophosphate, carbamate, and pyrethroid insecticides since the 1950s. Mechanisms of resistance are complex, but both oxidative and hydrolytic metabolism contribute to organophosphate, carbamate, and pyrethroid resistance facilitating cross-resistance between insecticide classes. History shows that Dvv insecticide resistance can evolve quickly and may persist in field populations even in the absence of selection. This suggests minimal fitness costs associated with Dvv resistance. In the transgenic era, insecticides function primarily as complementary tools with other Dvv management tactics to manage annual Dvv densities/crop injury and resistance over time.

scholarly journals Applying a Selection Experiment to Test for Fitness Costs of Bt Resistance in Western Corn Rootworm (Coleoptera: Chrysomelidae) and the Effect of Density on Fitness Costs

2020 ◽  
Vol 113 (5) ◽  
pp. 2473-2479
Author(s):  
Coy R St. Clair ◽  
Eric H Clifton ◽  
Mike W Dunbar ◽  
Kenneth E Masloski ◽  
Aubrey R Paolino ◽  
...  
Keyword(s):  
Larval Density ◽  
Ecological Factors ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Larval Rearing ◽  
Corn Rootworm ◽  
Fitness Costs ◽  
Bt Resistance ◽  
Rearing Density ◽  
Bacterium Bacillus

Abstract Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of corn and is often managed with transgenic corn producing insecticidal toxins from the bacterium Bacillus thuringiensis (Bt). This pest has developed field-evolved resistance to all commercially available Bt traits, beginning with Cry3Bb1 in 2009. Fitness costs may accompany Bt resistance, where individuals with alleles for Bt resistance have reduced fitness on non-Bt corn compared to Bt-susceptible individuals. In conjunction with non-Bt refuges, fitness costs can delay the evolution of Bt resistance. Importantly, ecological factors may affect the presence and magnitude of fitness costs. For western corn rootworm, available data suggest that fitness costs of Bt resistance may be present in some cases. Using two Cry3Bb1-resistant western corn rootworm strains (Hopkinton and Cresco), a fitness-cost experiment was performed by rearing rootworm in the absence of Bt for six generations to test for fitness costs of Cry3Bb1 resistance and the effect of larval rearing density on fitness costs. Fitness costs were detected for both strains; however, strains were still resistant to Cry3Bb1 corn at the end of the experiment. Cresco experienced a greater loss of resistance at low versus high density, but no effect of density was detected in Hopkinton. Our study shows that fitness costs can accompany Bt resistance in western corn rootworm and may be more pronounced under low larval density. Even though fitness costs were present, it appears that rootworm populations may remain resistant to Cry3Bb1 corn for years after resistance has evolved.

scholarly journals Maize hybrid and nutrient specific evaluation of the population dynamics and damage of the western corn rootworm (Diabrotica Virgifera Virgifera LeConte) in a long-term field experiment

2020 ◽  
Author(s):  
Árpád Illés ◽  
Csaba Bojtor ◽  
Seyed Mohammad Nasir Mousavi ◽  
L. Csaba Marton ◽  
Péter Ragán ◽  
...  
Keyword(s):  
Female Flower ◽  
Diabrotica Virgifera Virgifera ◽  
Nutrient Supply ◽  
Western Corn Rootworm ◽  
Egg Laying ◽  
Corn Rootworm ◽  
Root Damage ◽  
Potential Threat ◽  
Nitrogen Levels

AbstractAgricultural production is threatened by different invasive species, as their damage results in a serious loss of income. The aim of the research was the assessment of the swarming dynamics and damage of the western corn rootworm (WCR) adults and larvae. The experiment was carried out in monoculture fertilization long-term experiments and three maize hybrids compared for their reaction against WCR adult and larval damage under non-infested plots at different nitrogen levels. Differences among the hybrids have a lower effect on the damage of corn rootworm adults and larvae than the amount of applied nitrogen. The phosphorus-potassium are optimal levels, while nitrogen ranges from 0 to 300 kg and no nutrient supply took place in the control plots for 30 years. The number of adults located and feeding on the styles of the female flower recorded and the damage caused on the roots by larvae ranked on a modified Iowa scale. Nitrogen fertilization resulted in a change in the silking time. The lowest root damage observed in the case of the high nutrient treatment with an Iowa value of 3.18. The coincidence of the nourishment of adults and the egg-laying time with silking is a potential threat in terms of fertility. Based on the results, it found that the extent of root damage can be reduced through the optimal selection of the time and dose of nutrient supply, primarily that of nitrogen. In general, both larvae and adults can cause severe yield loss, but the method of control against them is different. The coincidence of the nourishment of adults and the egg-laying time with silking is a potential threat in terms of fertility.

scholarly journals Colonization history of the Western Corn Rootworm (Diabrotica virgifera virgifera) in North America: insights from random forest ABC using microsatellite data

2017 ◽  
Author(s):  
Eric Lombaert ◽  
Marc Ciosi ◽  
Nicholas J. Miller ◽  
Thomas W. Sappington ◽  
Aurélie Blin ◽  
...  
Keyword(s):  
Random Forest ◽  
North America ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Southern Mexico ◽  
Colonization History ◽  
Marker Loci ◽  
History Of

AbstractFirst described from western Kansas, USA, the western corn rootworm, Diabrotica virgifera virgifera, is one of the worst pests of maize. The species is generally thought to be of Mexican origin and to have incidentally followed the expansion of maize cultivation into North America thousands of years ago. However, this hypothesis has never been investigated formally. In this study, the genetic variability of samples collected throughout North America was analysed at 13 microsatellite marker loci to explore precisely the population genetic structure and colonization history of D. v. virgifera. In particular, we used up-to-date Approximate Bayesian Computation methods based on random forest algorithms to test a Mexican versus a central-USA origin of the species, and to compare various possible timings of colonization. This analysis provided strong evidence that the origin of D. v. virgifera was southern (Mexico, or even further south). Surprisingly, we also found that the expansion of the species north of its origin was recent - probably not before 1100 years ago - thus indicating it was not directly associated with the early history of maize expansion out of Mexico, a far more ancient event.

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