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

2005 ◽  
Vol 85 (4) ◽  
pp. 949-954 ◽  
Author(s):  
C. C. Knight ◽  
K. P. Pauls ◽  
M. K. Sears ◽  
A. W. Schaafsma

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)

Author(s):  
Joseph L Spencer ◽  
Timothy R Mabry ◽  
Eli Levine ◽  
Scott A Isard

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.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiping Niu ◽  
Adane Kassa ◽  
James Hasler ◽  
Samantha Griffin ◽  
Claudia Perez-Ortega ◽  
...  

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.


1990 ◽  
Vol 122 (6) ◽  
pp. 1177-1186 ◽  
Author(s):  
Y.S. Xie ◽  
J.T. Arnason ◽  
B.J.R. Philogène ◽  
J.D.H. Lambert ◽  
J. Atkinson ◽  
...  

Abstract2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), the major hydroxamic acid present in corn root, was studied for its effects on western corn rootworm, Diabrotica virgifera virgifera (LeConte). Exogenously applied DIMBOA caused mortality in western corn rootworm larvae feeding on fresh corn roots. The LC50 (lethal concentration for 50% mortality) value (fiducial limits) was 153 ppm (108–209) and the LC90 value was 917 ppm (560–2297). The deleterious effects of DIMBOA on western corn rootworm larvae possibly are due to both feeding deterrence and toxicity. In a replicated pot trial during two growing seasons, two corn lines developed by Agriculture Canada from CIMMYT collections, ITR 3872 with high DIMBOA content in roots, and NTR-2 Ger. 4042 with low DIMBOA content in roots, were evaluated for resistance to western corn rootworm larvae. The results indicated that the high DIMBOA line (but not the low DIMBOA line) stressed western corn rootworm larvae to produce inferior adults based on the measurement of adult emergence number, adult weight, and adult head-capsule width. The effect of western corn rootworm on both corn lines with different DIMBOA levels was measured based on plant growth parameters including plant height, stem thickness, plant fresh weight, root fresh weight, plant dry weight, and root dry weight. ITR 3872 (high DIMBOA) showed significantly less damage than NTR-2 Ger. 4042 (low DIMBOA) in almost all plant parameters measured. The results suggest that DIMBOA may in some instances contribute to the resistance of corn to western corn rootworm larvae.


2005 ◽  
Vol 53 (1) ◽  
pp. 71-79 ◽  
Author(s):  
E. Széll ◽  
I. Zsellér ◽  
G. Ripka ◽  
J. Kiss ◽  
G. Princzinger

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.


Genes ◽  
2016 ◽  
Vol 8 (1) ◽  
pp. 7 ◽  
Author(s):  
Ana Vélez ◽  
Elane Fishilevich ◽  
Natalie Matz ◽  
Nicholas Storer ◽  
Kenneth Narva ◽  
...  

2004 ◽  
Vol 70 (8) ◽  
pp. 4889-4898 ◽  
Author(s):  
James A. Baum ◽  
Chi-Rei Chu ◽  
Mark Rupar ◽  
Gregory R. Brown ◽  
William P. Donovan ◽  
...  

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.


2018 ◽  
Vol 111 (1) ◽  
pp. 161
Author(s):  
Špela MODIC ◽  
Primož ŽIGON ◽  
Aleš KOLMANIČ ◽  
Tone GODEŠA ◽  
Jaka RAZINGER

<p>The Western Corn Rootworm (WCR), <em>Diabrotica virgifera virgifera</em> 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 <em>Heterorhabditis bacteriophora</em> Poinar, 1976 (Rhabditida: Heterorhabditidae); (commercial product Dianem<sup>®</sup>) 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<sup>®</sup>, 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 <em>Heterorhabditis bacteriophora</em> 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.</p>


1989 ◽  
Vol 24 (2) ◽  
pp. 209-213 ◽  
Author(s):  
N. C. Elliott ◽  
G. R. Sutter ◽  
T. F. Branson ◽  
J. R. Fisher

A field study with controlled infestations of eggs of the western corn rootworm, Diabrotica virgifera virgifera LeConte, was conducted over a four-year period. The percentage of insects surviving to adulthood was significantly reduced at an infestation of 2400 eggs per 0.3 m of row compared with rates of 300, 600, and 1200 eggs per 0.3 m of row. Survival to adulthood varied among years suggesting that biotic or abiotic factors in the soil, possibly soil moisture, may have influenced survival. The Julian date associated with mean adult emergence was significantly later at the 2400 egg infestation rate than at lower rates. These results suggest that immature survival is reduced and developmental time increased at high population densities.


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