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 Survey of bacteria associated with western corn rootworm life stages reveals no difference between insects reared in different soils

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Dalton C. Ludwick ◽  
Aaron C. Ericsson ◽  
Lisa N. Meihls ◽  
Michelle L. J. Gregory ◽  
Deborah L. Finke ◽  
...  
Keyword(s):  
Pest Management ◽  
Life Stage ◽  
Management Strategies ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Corn Rootworm ◽  
Life Stages ◽  
Different Soils

Abstract Western corn rootworm (Diabrotica virgifera virgifera LeConte) is a serious pest of maize (Zea mays L.) in North America and parts of Europe. With most of its life cycle spent in the soil feeding on maize root tissues, this insect is likely to encounter and interact with a wide range of soil and rhizosphere microbes. Our knowledge of the role of microbes in pest management and plant health remains woefully incomplete, yet that knowledge could play an important role in effective pest management strategies. For this study, insects were reared on maize in soils from different locations. Insects from two different laboratory colonies (a diapausing and a non-diapausing colony) were sampled at each life stage to determine the possible core bacteriome. Additionally, soil was sampled at each life stage and resulting bacteria were identified to determine the possible contribution of soil to the rootworm bacteriome, if any. We analyzed the V4 hypervariable region of bacterial 16S rRNA genes with Illumina MiSeq to survey the different species of bacteria associated with the insects and the soils. The bacterial community associated with insects was significantly different from that in the soil. Some differences appear to exist between insects from non-diapausing and diapausing colonies while no significant differences in community composition existed between the insects reared on different soils. Despite differences in the bacteria present in immature stages and in male and female adults, there is a possible core bacteriome of approximately 16 operational taxonomic units (i.e., present across all life stages). This research may provide insights into Bt resistance development, improved nutrition in artificial rearing systems, and new management strategies.

scholarly journals Partial characterization of Bt resistance and the bacteriome of western corn rootworm

2018 ◽  
Author(s):  
◽  
Dalton C. Ludwick
Keyword(s):  
New Technologies ◽  
Management Strategies ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Control Measures ◽  
Corn Rootworm ◽  
Diabrotica Barberi ◽  
The Usa ◽  
Diabrotica Virgifera Virgifera Leconte ◽  
Northern Corn Rootworm

Western corn rootworm (Diabrotica virgifera virgifera LeConte) and northern corn rootworm (Diabrotica barberi (Smith and Lawrence)) are major pests of maize in the USA. These pests have been managed with a variety of tactics over the last century. Both Diabrotica spp. have adapted to crop rotation in different ways in certain regions of the USA as well as to some of the insecticides targeted at them. D. v. virgifera has adapted to more of the chemical control measures and transgenic control methods. Discussed in this review are the challenges associated with managing both species, and how current management strategies might be combined and implemented to help manage damage from these species. Also, we discuss the potential for new technologies, such as RNA interference, to be used in the future.

scholarly journals RNAi for Western Corn Rootworm Management: Lessons Learned, Challenges, and Future Directions

Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 57
Author(s):  
Molly Darlington ◽  
Jordan D. Reinders ◽  
Amit Sethi ◽  
Albert L. Lu ◽  
Partha Ramaseshadri ◽  
...  
Keyword(s):  
Environmental Protection Agency ◽  
Management Strategies ◽  
Housekeeping Genes ◽  
Diabrotica Virgifera Virgifera ◽  
The United States ◽  
Western Corn Rootworm ◽  
Lessons Learned ◽  
Corn Rootworm ◽  
In Planta ◽  
Commercial Use

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is considered one of the most economically important pests of maize (Zea mays L.) in the United States (U.S.) Corn Belt with costs of management and yield losses exceeding USD ~1–2 billion annually. WCR management has proven challenging given the ability of this insect to evolve resistance to multiple management strategies including synthetic insecticides, cultural practices, and plant-incorporated protectants, generating a constant need to develop new management tools. One of the most recent developments is maize expressing double-stranded hairpin RNA structures targeting housekeeping genes, which triggers an RNA interference (RNAi) response and eventually leads to insect death. Following the first description of in planta RNAi in 2007, traits targeting multiple genes have been explored. In June 2017, the U.S. Environmental Protection Agency approved the first in planta RNAi product against insects for commercial use. This product expresses a dsRNA targeting the WCR snf7 gene in combination with Bt proteins (Cry3Bb1 and Cry34Ab1/Cry35Ab1) to improve trait durability and will be introduced for commercial use in 2022.

scholarly journals Parameters for Successful Parental RNAi as An Insect Pest Management Tool in Western Corn Rootworm, Diabrotica virgifera virgifera

Genes ◽  
2016 ◽  
Vol 8 (1) ◽  
pp. 7 ◽  
Author(s):  
Ana Vélez ◽  
Elane Fishilevich ◽  
Natalie Matz ◽  
Nicholas Storer ◽  
Kenneth Narva ◽  
...  
Keyword(s):  
Pest Management ◽  
Insect Pest ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Management Tool ◽  
Corn Rootworm ◽  
Insect Pest Management ◽  
Diabrotica Virgifera

scholarly journals Western Corn Rootworm (WCR), Diabrotica Virgifera Virgifera Le Conte – Several Years of Research in Western Part of Romania

2010 ◽  
Vol 67 (1) ◽  
Author(s):  
Ioana GROZEA
Keyword(s):  
Developmental Stages ◽  
Control Strategies ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Activity Period ◽  
Main Role ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Corn Borer ◽  
Important Pest

Diabrotica virgifera virgifera Le Conte (Coleoptera: Chrysomelidae), known as western corn rootworm (WCR), is an important pest for maize crops from Romania, after corn borer larvae. Fourteen years ago, this pest has entered in our country. Since its introduction Diabrotica v. has been spreading in western part of Romania and many investigations were started by us to understand very well the morphology, eco-biology and control of the species. First occureance and activity period. The immature developmental stages of WCR (larvae, pupae, eggs) have been observed for the first time in Romania, in soil sample during 2000-2002. Adults’ activity developed from during June to September.The males have appeared earlier than females with approximate 4-6 days. The females have begun to lay eggs in middle of July. In soil, the larvae were observed from May to August and pupae were observed from June until August, too. Colour variability. In monitoring activities, the most of specialists use the color criterion for establishing males and females. However, this is not so precise method, because the great variability of color what is frequently in many populations. Therefore, we tried to eliminate any doubt regarding sex ratio. Influence of weather and geographical areas. Based on our data during 2003-2005, we can emphasize a very serious influence of air temperature and rainfall on WCR flight dynamics in adults. Regarding the altitude, we observed a decreasing number of WCR adults at once the altitude increase. Control strategies. In preventive control avoiding monoculture play a main role, because the larvae survived only maize roots. Some researches realized in western part pointed efficacy of seed treatments (using imidacloprid, clothianidin, thiametoxam) against larval populations. Very important is using a chemical product (thiametoxam) against adults (like an additionally product). From an-polluting method may mention follows: pheromone traps, color traps, autochthonous natural enemies. The spider species Argiope bruennichi (Araneae:Araneidae) and Theridion impressum (Araneae:Theriidae) are able to diminish significantly population of adults, especially in appearance of maize silk.

EVALUATION OF INFRARED THERMOMETRY AS A NON-DESTRUCTIVE METHOD TO DETECT FEEDING ON CORN ROOTS BY THE WESTERN CORN ROOTWORM (COLEOPTERA: CHRYSOMELIDAE)

1993 ◽  
Vol 125 (4) ◽  
pp. 643-655 ◽  
Author(s):  
A.W. Schaafsma ◽  
G.H. Whitfield ◽  
T.J. Gillespie ◽  
C.R. Ellis
Keyword(s):  
Grain Yield ◽  
Diabrotica Virgifera Virgifera ◽  
Kernel Weight ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Infrared Thermometry ◽  
Root Injury ◽  
Crop Maturity ◽  
Non Destructive

AbstractInfrared thermometry was investigated as a diagnostic tool to detect root injury in corn caused by feeding of the western corn rootworm, Diabrotica virgifera virgifera LeConte. Plots were infested with 50–1000 eggs per plant, and the study was conducted over 2 years. Differences (P < 0.05) in canopy temperatures were detected in severely infested plots in 6 out of 13 days and 7 out of 11 days on which measurements were made during the period of feeding by rootworm larvae in 1989 and 1990, respectively. Temperature differences between the air and leaves from infested plants were never greater than 3.5 °C and usually occurred within ± 1 °C. Feeding by rootworm larvae at infestation levels of less than 200 eggs per plant could not be detected with infrared thermometry. Above densities of 200 eggs per plant, increases in canopy temperatures corresponded with increases in the level of infestation with rootworm eggs, and with reduced plant height, and lower grain yield. Losses in grain yield due to rootworm infestation were manifested through smaller cobs and fewer seeds per cob. Kernel weight was not affected by rootworm feeding. Crop maturity was delayed at infestation levels of 1000 eggs per plant.Elevated canopy temperatures induced by rootworm feeding were detected through infrared thermometry in commercial corn fields, however differences (P < 0.05) in canopy temperatures were noted only after 10 July. Although these data show that elevated canopy temperatures induced by rootworm feeding can be detected with infrared thermometry, some inconsistency in results was observed. Various reasons for why the technique was not more reliable are discussed.

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 Western Corn Rootworm (Diabrotica virgifera virgifera LeConte) in Europe: Current Status and Sustainable Pest Management

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 195
Author(s):  
Renata Bažok ◽  
Darija Lemić ◽  
Francesca Chiarini ◽  
Lorenzo Furlan
Keyword(s):  
Pest Management ◽  
Management Strategies ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
European Countries ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Research Activities ◽  
Diabrotica Virgifera Virgifera Leconte ◽  
The Eu

Western corn rootworm (WCR), or Diabrotica virgifera virgifera LeConte, became a very serious quarantine maize pest in Europe in the mid-1990s. Between 1995 and 2010, European countries were involved in international projects to share information and plan common research for integrated pest management (IPM) implementation. Since 2011, however, common efforts have declined, and an overview of WCR population spread, density, and research is in serious need of update. Therefore, we retained that it was necessary to (1) summarize the research activities carried out in the last 12 years in various countries and the research topics addressed, and analyze how these activities have contributed to IPM for WCR and (2) present the current distribution of WCR in the EU and analyze the current population levels in different European countries, focusing on different management strategies. A review of scientific papers published from 2008 to 2020, in addition to direct interviews with experts in charge of WCR management in a range of European countries, was conducted. Over the past 12 years, scientists in Europe have continued their research activities to investigate various aspects of WCR management by implementing several approaches to WCR control. A considerable amount of new knowledge has been produced, contributing to the development of pest management strategies applicable in EU farming systems. Among the 10 EU countries analyzed, there is no country reporting economic damage on a large scale. Thanks to intensive research leading to specific agricultural practices and the EU Common Agricultural Policy, there are crop-rotation-based solutions that can adequately control this pest avoiding insecticide use.

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.

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