scholarly journals Predation capacity of soil-dwelling predatory mites on two major maize pests

Acarologia ◽  
2021 ◽  
Vol 61 (3) ◽  
pp. 577-580
Author(s):  
Antoine Pasquier ◽  
Thibault Andrieux ◽  
Paloma Martinez-Rodiguez ◽  
Elodie Vercken ◽  
Maxime Ferrero
Keyword(s):  
Diabrotica Virgifera Virgifera ◽  
Predatory Mites ◽  
Western Corn Rootworm ◽  
Laboratory Setting ◽  
Diabrotica Virgifera ◽  
Natural Conditions ◽  
Predator Species ◽  
First Instar ◽  
Predation Capacity ◽  
Stratiolaelaps Scimitus

The western corn rootworm Diabrotica virgifera virgifera (WCR), and the wireworm Agriotes sordidus (WW), whose eggs and first instar larvae develop in the first few centimeters of soil, are major crop pests. As soil-dwelling predatory mites are known as potential biocontrol agents against many pests, we investigated the predation capacity of Stratiolaelaps scimitus, Gaeolaelaps aculeifer and Macrocheles robustulus on immature stages of WCR and WW in a laboratory setting. While eggs of WCR and WW were never consumed, all three predator species attacked both WCR and WW first instar larvae. While these results need to be confirmed in natural conditions, our work identifies the early larval stage instead of the egg stage as the most vulnerable stage for control against WCR and WW with soil-dwelling predatory mites.

scholarly journals PREDATION CAPACITY OF SOIL-DWELLING PREDATORY MITES ON TWO GROUND BEETLE IMMATURE STAGES: A BIOLOGICAL CONTROL PERSPECTIVE FOR TWO MAJOR MAIZE PESTS

2019 ◽  
Author(s):  
Antoine Pasquier ◽  
Thibault Andrieux ◽  
Paloma Martinez-Rodriguez ◽  
Elodie Vercken ◽  
Maxime Ferrero
Keyword(s):  
Biological Control ◽  
Survival Analysis ◽  
Diabrotica Virgifera Virgifera ◽  
Predatory Mites ◽  
Biocontrol Agents ◽  
Immature Stages ◽  
Predator Species ◽  
First Instar ◽  
Predation Capacity ◽  
Stratiolaelaps Scimitus

ABSTRACTSoil-dwelling predatory mites already proved their efficiency as biocontrol agents against many pests (Carrillo et al. 2015). Western Corn Rootworm (WCR), (Diabrotica virgifera virgifera) and Wireworm (WW) (Agriotes sordidus) are important pests of various crops (Furlan et al. 2002; Krysan et al., 1986; Ritter and Richter 2013; Wesseler and Fall 2010) whose eggs and first instar larvae also inhabit the first centimeters of soil (Furlan 2004; Vidal et al., 2005). In order to evaluate the potential of predatory mites as biological control agents against WCR and WW, we investigated the predation capacity of Stratiolaelaps scimitus, Gaeolaelaps aculeifer and Macrocheles robustulus on immature stages of these two prey species. First, we observed if one or more species could feed upon eggs and first instar larvae as Prischmann et al. (2011) suggested for WCR. We then explored their predation abilities through time using a survival analysis to identify the best biocontrol agent among the species tested.Surprisingly, none of the predator species tested identified WCR or WW eggs as preys. However, at least 50% of WCR and WW first instar larvae have been attacked by G. aculeifer and M. robustulus. Stratiolaelaps scimitus showing a slightly lower efficiency (30% of preys attacked). The survival analysis confirmed this trend with slower predation dynamics for S. scimitus.These results show a potential of soil-dwelling predatory mites as biocontrol agents against WCR and WW. Furthermore, targeting the neonate stage instead of the egg stage in pest management strategies seems necessary for maximizing efficiency.

scholarly journals Detection of alternative splicing in Diabrotica virgifera virgifera LeConte, in association with Bt resistance using RNA-seq and PacBio Iso-Seq

2020 ◽  
Author(s):  
Zixiao Zhao ◽  
Christine G. Elsik ◽  
Bruce E. Hibbard ◽  
Kent S. Shelby
Keyword(s):  
Alternative Splicing ◽  
Matrix Protein ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Rna Seq ◽  
Bt Resistance ◽  
Bt Toxins ◽  
Alternatively Spliced

AbstractBackgroundAlternative splicing is one of the major mechanisms that increases transcriptome diversity in eukaryotes, including insect species that have gained resistance to pesticides and Bt toxins. In western corn rootworm (Diabrotica virgifera virgifera LeConte), neither alternative splicing nor its role in resistance to Bt toxins has been studied.ResultsTo investigate the mechanisms of Bt resistance we carried out single-molecule real-time (SMRT) transcript sequencing and Iso-seq analysis on resistant, eCry3.1Ab-selected and susceptible, unselected, western corn rootworm neonate midguts which fed on seedling maize with and without eCry3.1Ab for 12 and 24 hours. We present transcriptome-wide alternative splicing patterns of western corn rootworm midgut in response to feeding on eCry3.1Ab-expressing corn using a comprehensive approach that combines both RNA-seq and SMRT transcript sequencing techniques. We found that 67.73% of multi-exon genes are alternatively spliced, which is consistent with the high transposable element content of the genome. One of the alternative splicing events we identified was a novel peritrophic matrix protein with two alternative splicing isoforms. Analysis of differential exon usage between resistant and susceptible colonies showed that in eCry3.1Ab-resistant western corn rootworm, expression of one isoform was significantly higher than in the susceptible colony, while no significant differences between colonies were observed with the other isoform.ConclusionOur results provide the first survey of alternative splicing in western corn rootworm and suggest that the observed alternatively spliced isoforms of peritrophic matrix protein may be associated with eCry3.1Ab resistance in western corn rootworm.

Soybean Foliage Consumption Reduces Adult Western Corn Rootworm (Diabrotica virgifera virgifera)(Coleoptera: Chrysomelidae) Survival and Stimulates Flight

2021 ◽  
Author(s):  
Joseph L Spencer ◽  
Timothy R Mabry ◽  
Eli Levine ◽  
Scott A Isard
Keyword(s):  
Wind Tunnel ◽  
Crop Rotation ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Egg Laying ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Egg Maturation ◽  
Behavioral Resistance ◽  
Collection Sites

Abstract Western corn rootworm, Diabrotica virgifera virgifera LeConte, biology is tied to the continuous availability of its host (corn, Zea mays L.). Annual rotation of corn with a nonhost, like soybean (Glycine max (L.) Merrill) was a reliable tactic to manage western corn rootworm. Behavioral resistance to annual crop rotation (rotation resistance) allowed some eastern U.S. Corn Belt populations to circumvent rotation by laying eggs in soybean and in cornfields. When active in soybean, rotation-resistant adults commonly consume foliage, in spite of detrimental effects on beetle survival. Rotation-resistant beetle activity in soybean is enabled by the expression of certain proteinases and an adapted gut microbiota that provide limited protection from soybean antiherbivore defenses. We investigated the effects of corn and soybean herbivory on rotation-resistant female survival and initiation of flight using mortality assays and wind tunnel flight tests. Among field-collected females tested with mortality assays, beetles from collection sites in a cornfield survived longer than those from collection sites in a soybean field. However, reduced survival due to soybean herbivory could be restored by consuming corn tissues. Field-collected beetles that fed on a soybean tissue laboratory diet or only water were more likely to fly in a wind tunnel than corn-feeding beetles. Regardless of collection site and laboratory diet, 90.5% of beetles that flew oriented their flights upwind. Diet-related changes in the probability of flight provide a proximate mechanism for interfield movement that facilitates restorative feeding and the survival of females previously engaged in soybean herbivory. Rotation-resistant western corn rootworm females feeding on soybean tissues experience reduced survival in mortality assays and display increased flight probability (which may facilitate flight back to a cornfield where consumption of host tissues improves survival potential and facilitates maturation of eggs). The consequences of soybean herbivory provide a proximal mechanism for behavioral resistance to crop rotation. Increased egg-laying probability while feeding on soybean tissues, facilitation of egg maturation while feeding on corn tissues, and interfield movement are previously documented consequences.

scholarly journals Inheritance and Fitness Costs of Cry3Bb1 Resistance in Diapausing Field Strains of Western Corn Rootworm (Coleoptera: Chrysomelidae)

2020 ◽  
Vol 113 (6) ◽  
pp. 2873-2882
Author(s):  
Ram B Shrestha ◽  
Aaron J Gassmann
Keyword(s):  
Developmental Rate ◽  
Diabrotica Virgifera Virgifera ◽  
Dry Mass ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Adult Size ◽  
Inheritance Of Resistance ◽  
Diabrotica Virgifera ◽  
Fitness Costs ◽  
Diabrotica Virgifera Virgifera Leconte

Abstract Field-evolved resistance to Cry3Bb1 corn by western corn rootworm, Diabrotica virgifera virgifera LeConte (Colleoptera: Chrysomellidae), has been reported in field populations in Iowa, Illinois, Nebraska, and Minnesota. Inheritance and fitness costs associated with Cry3Bb1 resistance have been determined for non-diapausing laboratory strains of western corn rootworm with either laboratory-selected resistance or field-derived resistance. However, information on inheritance and fitness costs of Cry3Bb1 resistance in the diapausing field populations is lacking. In this study, we determined the inheritance of Cry3Bb1 resistance for four diapausing field strains of western corn rootworm using plant-based bioassays. We also determined the fitness costs for eight diapausing field populations in a greenhouse experiment. We found that Cry3Bb1 resistance was an autosomal trait and that the inheritance of resistance was mostly non-recessive; however, there was some variation in the dominance of Cry3Bb1 resistance. We did not find evidence of fitness costs affecting survival to adulthood, developmental rate, or adult dry mass. However, we did detect a fitness cost affecting adult size. The results of this study will add to the current understanding of field-evolved resistance to Cry3Bb1 corn by western corn rootworm and help in developing better strategies to manage resistance.

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

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.

scholarly journals Prediction of adult western corn rootworm (Diabrotica virgifera virgifera LeConte) emergence

2013 ◽  
Vol 49 (No. 2) ◽  
pp. 89-97
Author(s):  
T. Středa ◽  
O. Vahala ◽  
H. Středová
Keyword(s):  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Threshold Temperature ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Degree Days ◽  
The Czech Republic ◽  
Sum Of Effective Temperatures ◽  
Effective Temperatures ◽  
Diabrotica Virgifera Virgifera Leconte

The sum of effective temperatures (SET) of adult western corn rootworm (WCR) occurrence was determined based on several criteria. The risk of WCR occurrence was mapped, and the areas of continuous reproduction of WCR in the Czech Republic were identified. The daily soil SET was observed until the initial adult WCR occurrence, and it ranged from 414 degree days (DD) when the lower threshold temperature (LTT) was 12.5°C at 0.02 m depth to 719 DD (LTT of 10°C at a depth of 0.05 m). The daily air SET ranged from 415 DD (LTT 12.5°C at a height of 2 m) to 726 DD (LTT of 10°C at a height of 0.05 m).  

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