A Composed‐Error Model for Estimating Pest‐Damage Functions and the Impact of the Western Corn Rootworm Soybean Variant in Illinois

Glyphosate-resistant (GR) volunteer corn has emerged as a problematic weed in corn:soybean rotational systems, partly because of the rapid increase in adoption of corn hybrids that contain traits for both glyphosate and insect resistance. Volunteer GR corn can decrease soybean yields. The objectives of this study were to quantify the impact of volunteer corn on soybean growth and yield and determine how volunteer corn densities affect western corn rootworm (WCR) emergence. Volunteer corn seed was hand-planted at targeted densities of 0.5, 2, 4, 8, 12, and 16 seeds m−2at soybean planting and 21 d after planting to evaluate both early- and late-emerging cohorts. WCR emergence was assessed with the use of field emergence traps placed over individual corn plants in the 0.5- and 16-plants-m−2plots in 2008 and 2009. In 2010, WCR emergence traps were also placed over individual and clumped volunteer corn plants at densities of two and eight plants m−2. Soybean yield reductions ranged from 10 to 41% where early-emerging volunteer corn densities ranged from 0.5 to 16 plants m−2. No soybean yield loss occurred with the late-emerging cohort of volunteer corn. Twice as many adult WCRs emerged from a single volunteer corn plant growing at densities of 8 and 16 plants m−2, compared with plots containing 0.5 and 2 plants m−2. These results demonstrate that controlling volunteer corn will not only prevent soybean yield loss, but also may reduce the risk of WCR larval survival after exposure to Bt (Bacillus thuringiensisBerliner derived) corn.

Download Full-text

Harmonic Radar: Assessing the Impact of Tag Weight on Walking Activity of Colorado Potato Beetle, Plum Curculio, and Western Corn Rootworm

Journal of Economic Entomology ◽

10.1603/ec09113 ◽

2010 ◽

Vol 103 (1) ◽

pp. 63-69 ◽

Cited By ~ 15

Author(s):

G. Boiteau ◽

C. Vincent ◽

F. Meloche ◽

T. C. Leskey

Keyword(s):

Colorado Potato Beetle ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Plum Curculio ◽

Harmonic Radar ◽

Potato Beetle ◽

Walking Activity ◽

The Impact

Download Full-text

The effects of drought stress and western corn rootworm feeding on maize root biology

10.32469/10355/64002 ◽

2010 ◽

Author(s):

◽

Kristen A. Leach

Keyword(s):

Gene Expression ◽

Mirna Expression ◽

Expression Patterns ◽

Primary Root ◽

Diabrotica Virgifera Virgifera ◽

Western Corn Rootworm ◽

Specific Response ◽

Corn Rootworm ◽

Defense Genes ◽

The Impact

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Drought and western corn rootworm (WCR), Diabrotica virgifera virgifera, can have substantial impacts on the potential yield of maize, Zea may L. Maize lines were selected to survey the level of diversity available for primary root elongation maintenance under water stress and three WCR-related traits: WCR damage, root size, and root regrowth. Data analysis suggests that lines belonging to the Tropical/Semi-tropical population structure group are a significant source of alleles which would improve resistance/tolerance to these stressors. Further analysis of the WCR trait data found significant correlations with agronomically important traits related to plant maturity, confirming the impact of maize phenology on WCR damage. This indicates that phase change or changes in biochemical pathways as the plant matures may serve as additional criteria to effectively select germplasm that is resistant/tolerant to WCR feeding. In an effort to identify maize genes responsible for defense against WCR herbivory, a transcriptome analysis discovered that the presence of an endosymbiont, Wolbachia, down-regulated the expression of defense genes. Gene expression time courses suggest WCR elicits a response to herbivory by WCR+wb which was confirmed by a more extensive analysis of the microarray data. Maize defense genes were found to be down-regulated in agreement with the previous study. Transcriptional down-regulation may be the result of transposable element interference or post-transcriptional regulation by small RNAs, i.e. siRNAs or miRNAs. Three classes of miRNA were identified based on their response to WCR+wb, WCR-wb, and control treatments in the CRW3 germplasm; WCR-specific response, Wolbachia-specific response, and generalized defense response. Models based on the miRNA expression patterns along with information from the literature about their targets and downstream effects enabled us to predict phenotypes based on miRNA mediated-changes in gene expression. Results of the GO term enrichment analysis together with miRNA expression analysis support miRNA-mediated post-translational modification as one mechanism underlying the Wolbachia-associated changes in maize gene expression.

Download Full-text

A Promising Predator-In-First Strategy to Control Western Corn Rootworm Population in Maize Fields

Agronomy ◽

10.3390/agronomy11101984 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1984

Author(s):

Antoine Pasquier ◽

Lucie S. Monticelli ◽

Adeline Moreau ◽

Benjamin Kaltenbach ◽

Candice Chabot ◽

...

Keyword(s):

Large Scale ◽

Plant Protection ◽

Predatory Mite ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Critical Stage ◽

Maize Production ◽

Maize Field ◽

Maize Plants ◽

The Impact

Western Corn Rootworm is a pest of maize that mostly damages roots. Many alternative strategies have been explored to control this species, with little or non-lasting success, and it remains a threat to maize production worldwide. Gaeolaelaps aculeifer, a soil-dwelling predatory mite that inhabits the first few centimeters of the soil, showed high predatory potential against WCR larvae in the laboratory. In this study, we explored the efficiency of G. aculeifer against WCR in more realistic contexts. First, we infested maize plants isolated in pots in a greenhouse with WCR, and tested the impact of different densities of mites on plant protection. Using standard indicators of WCR population presence and impact, we confirmed that G. aculeifer has the potential to control WCR at densities starting from 100 mites/plant. Then, considering that the release of a large amount of biocontrol agents at WCR emergence might be too costly and constraining for large-scale implementation, we tested the efficiency of a predator-in-first strategy in a maize field infested by WCR. The goal was to introduce fewer G. aculeifer combined with Aleuroglyphus ovatus eggs as an alternative food source in order to let the mite population grow in the field and reach sufficient density at the critical stage for protection. This strategy gave comparable results to pesticide on all indicators examined in our field trial, highlighting the potential to sustainably manage this pest.

Download Full-text