Evaluation of the Field Efficacy of Heterorhabditis Bacteriophora Poinar (Rhabditida: Heterorhabditidae) and Synthetic Insecticides for the Control of Western Corn Rootworm Larvae

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera, Chrysomelidae), is an important insect pest of maize in North America and Central and Eastern Europe. In Central Europe, the larvae emerge in May and its three instars feed intensively on maize roots in June, causing plant lodging that leads to a loss of economic yield. A three-year field experiment (2016–2018) was conducted to compare the effectiveness i) of soil-applied granular insecticide based on the active ingredient tefluthrin, ii) of maize seeds dressed with thiacloprid, and iii) entomopathogenic nematodes Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae, product Dianem) against WCR larvae. An additional treatment with alcohol ethoxylate (i.e., soil conditioner) mixed with entomopathogenic nematodes was performed in 2017 and 2018 to check for any increase of entomopathogenic nematodes’ effectiveness. Field tests were carried out in two fields infested naturally with a WCR pest population, one in Bučečovci (Eastern Slovenia) and the other in Šmartno pri Cerkljah (northern Slovenia), exhibiting dissimilar pedo-climatic conditions and soil pest densities. The treatments were performed in five replicates per experiment in each year. The efficacy of the treatments was very similar at both locations, despite the approximately five-fold lower WCR soil pest densities in northern than in eastern Slovenia, as well as being constant over time. The largest number of WCR beetles was observed in the negative control, followed by that of beetles subjected to thiacloprid treatment (insignificant decrease taking into account the entire three-year dataset). Treatments with tefluthrin (44.1 ± 11.7%), H. bacteriophora (46.2 ± 7.4%), and H. bacteriophora + alcohol ethoxylate (49.2 ± 1.8%) significantly decreased the numbers of emerging beetles. Treatments of thiacloprid, H. bacteriophora, and H. bacteriophora + alcohol ethoxylate additionally led to significantly increased maize plant weights. Furthermore, entomopathogenic nematodes were able to persist in maize fields for almost five months at both experimental locations in silty and sandy loam soils. It was concluded that the control of WCR larvae in maize using the entomopathogenic nematode H. bacteriophora is as effective as a tefluthrin treatment, and could thus offer a sustainable Diabrotica v. virgifera biological control management option in Europe.

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Effectiveness of different control measures against western corn rootworm larvae Diabrotica virgifera virgifera LeConte, 1868

Acta agriculturae Slovenica ◽

10.14720/aas.2018.111.1.15 ◽

2018 ◽

Vol 111 (1) ◽

pp. 161

Author(s):

Špela MODIC ◽

Primož ŽIGON ◽

Aleš KOLMANIČ ◽

Tone GODEŠA ◽

Jaka RAZINGER

Keyword(s):

Biological Control ◽

Active Substance ◽

Insect Pest ◽

Diabrotica Virgifera Virgifera ◽

Heterorhabditis Bacteriophora ◽

Western Corn Rootworm ◽

Population Pressure ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Inundative Biological Control

The Western Corn Rootworm (WCR), Diabrotica virgifera virgifera LeConte, 1868, [Coleoptera, Chrysomelidae], whose larvae cause damage to maize roots, is an important economic insect pest in America and Europe. Its larvae are usually controlled by granular soil insecticides or insecticide-treated seeds. Biological control options, such as entomopathogenic nematodes (EPN) have played an important role as an alternative for synthetic chemical insecticides. Therefore, for the WCR larvae control we compared the effectiveness of inundative biological control on the basis of EPN Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae); (commercial product Dianem®) and the conventional insecticides Force 1.5 g (active substance tefluthrin) from the group of synthetic pyrethriods and Sonido (active substance thiacloprid) from the group of neonicotinoids. Field experiments were carried out at geographically different locations under different population pressure of the insect pest in a), Bučečovci (Prlekija; Eastern Slovenia) and b), Šmartno (Gorenjska: northern Slovenia). The differences between the treatments were very similar at both locations; although the population of WCR in Gorenjska was approximately 5-fold lower than in Prlekija. The highest number of WCR beetles was caught in the negative control, followed by the product Sonido, Force and Dianem®, in decreasing order. Statistical analysis showed that only in the treatment where EPN were used, significantly less WCR was caught than in the control. The results of the WCR larvae control in maize using Heterorhabditis bacteriophora are comparable to published literature. However, the weather conditions in the 2016 trial were very favorable for the development and survival of EPN in the soil.

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Functional validation of DvABCB1 as a receptor of Cry3 toxins in western corn rootworm, Diabrotica virgifera virgifera

Scientific Reports ◽

10.1038/s41598-020-72572-9 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Xiping Niu ◽

Adane Kassa ◽

James Hasler ◽

Samantha Griffin ◽

Claudia Perez-Ortega ◽

...

Keyword(s):

Resistant Strain ◽

Insect Pest ◽

Amino Acid Level ◽

Diabrotica Virgifera Virgifera ◽

Western Corn Rootworm ◽

Hek293 Cells ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Functional Validation ◽

Bt Toxins

Abstract Western corn rootworm (WCR), Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), is a serious insect pest in the major corn growing areas of North America and in parts of Europe. WCR populations with resistance to Bacillus thuringiensis (Bt) toxins utilized in commercial transgenic traits have been reported, raising concerns over their continued efficacy in WCR management. Understanding the modes of action of Bt toxins is important for WCR control and resistance management. Although different classes of proteins have been identified as Bt receptors for lepidopteran insects, identification of receptors in WCR has been limited with no reports of functional validation. Our results demonstrate that heterologous expression of DvABCB1 in Sf9 and HEK293 cells conferred sensitivity to the cytotoxic effects of Cry3A toxins. The result was further validated using knockdown of DvABCB1 by RNAi which rendered WCR larvae insensitive to a Cry3A toxin. However, silencing of DvABCB2 which is highly homologous to DvABCB1 at the amino acid level, did not reduce the sensitivity of WCR larvae to a Cry3A toxin. Furthermore, our functional studies corroborate different mode-of-actions for other insecticidal proteins including Cry34Ab1/35Ab1, Cry6Aa1, and IPD072Aa against WCR. Finally, reduced expression and alternatively spliced transcripts of DvABCB1 were identified in a mCry3A-resistant strain of WCR. Our results provide the first clear demonstration of a functional receptor in the molecular mechanism of Cry3A toxicity in WCR and confirmed its role in the mechanism of resistance in a mCry3A resistant strain of WCR.

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Strategies for controlling western corn rootworm (Diabrotica virgifera virgifera)

Acta Agronomica Hungarica ◽

10.1556/aagr.53.2005.1.9 ◽

2005 ◽

Vol 53 (1) ◽

pp. 71-79 ◽

Cited By ~ 6

Author(s):

E. Széll ◽

I. Zsellér ◽

G. Ripka ◽

J. Kiss ◽

G. Princzinger

Keyword(s):

Life Cycle ◽

Seed Treatment ◽

Large Scale ◽

Insect Pest ◽

Diabrotica Virgifera Virgifera ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Non Profit ◽

Small Plot

Western corn rootworm (WCR) first appeared in Europe near Belgrade airport in 1992. The first adult of this species was found near Mórahalom, in the southern part of Hungary, on 30th June 1995. Small-plot trials were started in Szeged (Cereal Research Non-Profit Co.) and large-scale trials in Mezohegyes (Ménesbirtok Ltd.) in 1996 to elaborate strategies to control this insect pest. To make the work more efficient, eight experts working at different institutions formed a team. At the same time, monitoring was begun on when and where the insect appeared and in what numbers. The experiments were adapted to the life cycle of the species. WCR has one generation per year, laying eggs that overwinter. Larvae begin to hatch in late May to mid-June. Adults emerge by mid-July and survive till early October. They lay eggs in abundance from mid-July to late August. Trials were conducted to control WCR both with and without chemicals. For adult control pesticides were sprayed from an aircraft or using a field sprayer. Larval control involved seed treatment with insecticide or the use of soil insecticide at planting or at cultivation.

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Oviposition site selected by the western corn rootworm (Diabrotica virgifera virgifera Leconte) in southern Ontario strip plots

Canadian Journal of Plant Science ◽

10.4141/p04-159 ◽

2005 ◽

Vol 85 (4) ◽

pp. 949-954 ◽

Cited By ~ 4

Author(s):

C. C. Knight ◽

K. P. Pauls ◽

M. K. Sears ◽

A. W. Schaafsma

Keyword(s):

Insect Pest ◽

Adult Emergence ◽

Diabrotica Virgifera Virgifera ◽

Conclusive Evidence ◽

Western Corn Rootworm ◽

Egg Laying ◽

Larval Feeding ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Southern Ontario

Western corn rootworm (WCR), Diabrotica virgifera virgifera L., is the most serious insect pest of corn, Zea mays L., in North America. Crop rotation had successfully controlled this pest until the late 1980s when a new biotype that lays its eggs in non-corn crops was discovered in Illinois. This biotype has spread to parts of Indiana, Michigan, and Ohio, and threatens Ontario. By using emergence cages, Pherocon Am® sticky traps and corn root ratings, egg-laying behaviour of WCR in Ontario was assessed in strip crop settings that represent typical cropping systems of southern Ontario. WCR adults were active in both soybean and winter wheat fields in July and August. Larval feeding and adult emergence in first-year corn fields following soybean and wheat were similar, confirming that oviposition did occur in both crops. These data do not, however, provide conclusive evidence for the presence of the rotation resistant WCR in Ontario because previous studies have demonstrated that WCR are capable of utilizing other crops for oviposition. Key words: Western corn rootworm, Diabrotica virgifera virgifera, strip plots, corn, soybean, wheat (winter)

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The possibility of using entomopathogenic nematodes and entomophages as bioagents of the western corn rootworm (Diabrotica virgifera virgifera Le Conte)

Interdepartmental Thematic Scientific Collection of Plant Protection and Quarantine ◽

10.36495/1606-9773.2018.64.191-197 ◽

2018 ◽

pp. 191-197

Author(s):

A. Sikura ◽

V. Gunchak

Keyword(s):

Entomopathogenic Nematodes ◽

Diabrotica Virgifera Virgifera ◽

Biological Agents ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Diabrotica Virgifera

The article presents the results of studies on the possibility of using entomopathogenic nematodes and entomophages against the western corn rootworm. It is established that the bioagents under study are able to regulate the number of Diabrotica virgifera virgifera Le Conte. The obtained results showed the prospects of using these biological agents for phytophage control.

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Screening of entomopathogenic nematodes for virulence against the invasive western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) in Europe

Bulletin of Entomological Research ◽

10.1079/ber2005379 ◽

2005 ◽

Vol 95 (5) ◽

pp. 473-482 ◽

Cited By ~ 33

Author(s):

S. Toepfer ◽

C. Gueldenzoph ◽

R.-U. Ehlers ◽

U. Kuhlmann

Keyword(s):

Biological Control ◽

Entomopathogenic Nematode ◽

Larval Mortality ◽

Nematode Species ◽

Diabrotica Virgifera Virgifera ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Biological Control Agents ◽

Steinernema Glaseri

AbstractEntomopathogenic nematode species available in Europe were screened for their efficacy against both the root-feeding larvae and silk-feeding adults of the western corn rootworm, Diabrotica virgifera virgifera LeConte. Laboratory screening tests were aimed at the selection of candidate biological control agents for the management of this invasive alien pest in Europe. Steinernema glaseri, S. arenarium, S. abassi, S. bicornutum, S. feltiae, S. kraussei, S. carpocapsae and Heterorhabditis bacteriophora were studied to determine their virulence against third instar larvae and adults of D. v. virgifera in small-volume arenas (using nematode concentrations of 0.5, 0.8, 7.9 and 15.9 infective juveniles cm–2). All nematode species were able to invade and propagate in D. v. virgifera larvae, but adults were rarely infected. At concentrations of 7.9 and 15.9 cm–2, S. glaseri, S. arenarium, S. abassi and H. bacteriophora caused the highest larval mortality of up to 77%. Steinernema bicornutum, S. abassi, S. carpocapsae and H. bacteriophora appeared to have a high propagation level, producing 5970±779, 5595±811, 5341±1177 and 4039±1025 infective juveniles per larva, respectively. Steinernema glaseri, S. arenarium, S. feltiae, S. kraussei and H. bacteriophora were further screened at a concentration of 16.7 nematodes cm–2 against third instar larvae in medium-volume arenas (sand-filled trays with maize plants). Heterorhabditis bacteriophora, S. arenarium and S. feltiae caused the highest larval mortality with 77±16.6%, 67±3.5%, and 57±17.1%, respectively. In a next step, criteria for rating the entomopathogenic nematode species were applied based on results obtained for virulence and propagation, and for current production costs and availability in Europe. These criteria were then rated to determine the potential of the nematodes for further field testing. Results showed the highest potential in H. bacteriophora, followed by S. arenarium and S. feltiae, for further testing as candidate biological control agents.

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

Genes ◽

10.3390/genes8010007 ◽

2016 ◽

Vol 8 (1) ◽

pp. 7 ◽

Cited By ~ 9

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

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Binary Toxins from Bacillus thuringiensis Active against the Western Corn Rootworm, Diabrotica virgifera virgifera LeConte

Applied and Environmental Microbiology ◽

10.1128/aem.70.8.4889-4898.2004 ◽

2004 ◽

Vol 70 (8) ◽

pp. 4889-4898 ◽

Cited By ~ 26

Author(s):

James A. Baum ◽

Chi-Rei Chu ◽

Mark Rupar ◽

Gregory R. Brown ◽

William P. Donovan ◽

...

Keyword(s):

Bacillus Thuringiensis ◽

Insect Pest ◽

Diabrotica Virgifera Virgifera ◽

The United States ◽

Western Corn Rootworm ◽

Binary Toxin ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Crystal Proteins ◽

Genes Encoding

ABSTRACT 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 approximate molecular masses of 13 to 15 kDa and 44 kDa. Insect bioassays demonstrated that both protein classes are required for insecticidal activity against this rootworm species. The genes encoding these proteins are organized in apparent operons and are associated with other genes encoding crystal proteins of unknown function. The antirootworm proteins produced by B. thuringiensis strains EG5899 and EG9444 closely resemble previously described crystal proteins of the Cry34A and Cry35A classes. The antirootworm proteins produced by strain EG4851, designated Cry34Ba1 and Cry35Ba1, represent a new binary toxin. Genes encoding these proteins could become an important component of a sustainable resistance management strategy against this insect pest.

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Calcium-alginate beads as a formulation for the application of entomopathogenic nematodes to control rootworms

Journal of Pest Science ◽

10.1007/s10340-021-01349-4 ◽

2021 ◽

Author(s):

Jinwon Kim ◽

Ivan Hiltpold ◽

Geoffrey Jaffuel ◽

Ilham Sbaiti ◽

Bruce E. Hibbard ◽

...

Keyword(s):

Entomopathogenic Nematodes ◽

Uv Light ◽

Diabrotica Virgifera Virgifera ◽

Alginate Beads ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Biological Control Agents ◽

Metabolic Arrest ◽

Root Feeding

AbstractEntomopathogenic nematodes (EPN) have great potential as biological control agents against root-feeding insects. They have a rapid and long-lasting mode of action, minimal adverse effects on the environment and can be readily mass-produced. However, they have a relatively short shelf-life and are susceptible to desiccation and UV light. These shortcomings may be overcome by encapsulating EPN in Ca2+-alginate hydrogels, which have been shown to provide a humid and UV protective shelter. Yet, current Ca2+-alginate formulations do not keep EPN vigorous and infectious for a prolonged period of time and do not allow for their controlled release upon application. Here, we introduce solid Ca2+-alginate beads which we supplemented with glycerol to better retain the EPN during storage and to ensure a steady release when applied in soil. Glycerol-induced metabolic arrest in EPN (Heterorhabditis bacteriophora) resulting in quiescence and total retainment of EPN when added to beads made with 0.5% sodium alginate and 2% CaCl2·2H2O solutions. More than 4,000 EPN could be embedded in a single 4–5-mm diameter bead, and quiescence could be broken by adding water, after which the EPN readily emerged from the beads. In a field trial, the EPN beads were as effective in reducing root damage by the western corn rootworm (WCR, Diabrotica virgifera virgifera) as EPN that were applied in water. Although further improvements are desirable, we conclude that Ca2+-alginate beads can provide an effective and practical way to apply EPN for the control of WCR larvae.

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Potential of controlling insect pests of corn using entomopathogenic nematodes

Canadian Journal of Plant Science ◽

10.4141/p00-116 ◽

2001 ◽

Vol 81 (4) ◽

pp. 783-787 ◽

Cited By ~ 12

Author(s):

E. Riga ◽

J. Whistlecraft ◽

J. Potter

Keyword(s):

European Corn Borer ◽

Entomopathogenic Nematodes ◽

Insect Pests ◽

Insect Pest ◽

Fall Armyworm ◽

Nematode Species ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Pest Species ◽

Corn Borer

A series of experiments was performed in the laboratory and in the greenhouse to assess the efficacy of the entomopathogenic nematodes, Steinernema glaseri or S. feltiae in decreasing the numbers of European corn borer, fall armyworm, western corn rootworm and the seedcorn maggot in corn. Both nematode species effectively controlled the four insect pest species. During greenhouse experiments, the number of plants protected with entomopathogenic nematodes against these insect pests was significantly higher than in the untreated controls. Similar results were obtained in a microplot study of corn infected with the European corn borer, the western corn rootworm and the seedcorn maggot. The application of a single nematode species against several insect pests has economic advantages. In addition, both S. glaseri and S. feltiae overwintered and survived in the field until the next growing season. Key words: Entomopathogenic nematodes, sweet corn, European corn borer, fall armyworm, seedcorn maggot, western corn rootworm

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