scholarly journals LEVEL OF LARVAL ATACK ON MAIZE ROOTS AS A CONSEQUENCE OF ARTIFICIAL INFESTATION WITH WESTERN CORN ROOTWORM EGGS

AGROFOR ◽  
2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Snežana TANASKOVIĆ ◽  
Branka POPOVIĆ ◽  
Sonja GVOZDENAC ◽  
Zsolt KARPÁTI ◽  
Csengele BÓGNAR ◽  
...  
Keyword(s):  
Ostrinia Nubilalis ◽  
Control Plant ◽  
Western Corn Rootworm ◽  
Corn Belt ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Maize Field ◽  
Artificial Infestation ◽  
Maize Roots ◽  
Vojvodina Province

The Western corn rootworm (WCR), Diabrotica virgifera sp. virgifera(Col.,Chrysomelidae), is an oligophagous pest native in America. WCR is a maizepest present in all regions of the Corn Belt. It is an invasive species which was, inEurope, first identified in Serbia, in 1992, near the Belgrade airport. The presenceof this pest in maize field can cause losses and plant damages up to 100%. A fieldexperiment was carried out in Bečej, Vojvodina province (Serbia), during 2014 and2015. In the field, 96 plants (maize cultivar NS 640), arranged in 48 pairs wereselected. Each pair consisted of one plant artificially infested with WCR eggs (Dplant) and the control plant (C plant). In both years, the experiment in the field wasregularly inspected, once a week. During each observation, the presence of "gooseneck" symptoms was recorded, and the number of plants damaged by the mostimportant stem boring and leaf feeding insects (Ostrinia nubilalis, Helicoverpaarmigera, H. zeae, aphids, mites, cicadas, etc. ) was counted. Root damages wereassessed at the end of the experiment (September), according to Ostlie and Notzel(1987), on scale 1-6. Comparing the root damages on C and D plants, less rootdamages were established on C plants. Only six i. e. four D plants had healthy roots(rate 1) during 2014 and 2015, respectively. Between D plants in 2014, the mostdamaged were14 plants, with the rate 3 (least one root chewed to within 1½ inches(3. 8 cm) of the plant). In 2015, severe damages were registered on 18 plants,which were ranked as level 6 (with three or more nodes destroyed). Only two Cplants during vegetation 2014-2015were registered with damages with rate 5 (twonodes destroyed) and rate 6 (three or more nodes destroyed), respectively.

scholarly journals Repellent Effects of Methyl Anthranilate on Western Corn Rootworm Larvae (Coleoptera: Chrysomelidae) in Soil Bioassays

2018 ◽  
Vol 112 (2) ◽  
pp. 683-690
Author(s):  
E J Bernklau ◽  
B E Hibbard ◽  
L B Bjostad
Keyword(s):  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Moist Soil ◽  
Soil Environment ◽  
Methyl Anthranilate ◽  
Maize Roots ◽  
Unsterilized Soil ◽  
Diabrotica Virgifera Virgifera Leconte

Abstract Methyl anthranilate (MA), a compound in maize roots that is repellent to western corn rootworm larvae (Diabrotica virgifera virgifera LeConte) was tested in behavioral bioassays in a soil environment. MA prevented larvae from locating roots of a maize seedling, and the repellency strengthened with increasing rates of MA. In a simple push–pull strategy between an MA-treated seedling and an untreated seedling, granules containing 0.1 mg/g MA pushed larvae to the untreated seedling. This push effect increased with dose, with 90% repellency observed for the highest dose tested (100 mg/g). Chemical analysis showed that MA concentrations remained high for 4 wk in dry, sterilized or unsterilized soil, but declined rapidly in moist soil. After 7 d, 50% less MA was recovered in moist, sterilized soil than in dry soil, and only a trace of MA remained in unsterilized moist soil, suggesting that both moisture and microbial activity contributed to the loss of MA. Various (MA) carrier granules were tested in bioassays after aging in moist soil. After 1 d, all of the MA granules were repellent at the 10 mg/g rate and clay granules were also effective at 1 mg/g. After 1 wk, only molecular sieve granules elicited repellency, but that activity disappeared after 2 wk. These results demonstrate that MA is repellent to western corn rootworm larvae in the soil environment and may have potential as a rootworm treatment if formulations can be developed that protect the material from decomposition in the soil.

scholarly journals Estimation of Cry3Bb1 resistance allele frequency in field populations of western corn rootworm using a genetic marker

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alan Willse ◽  
Lex Flagel ◽  
Graham Head
Keyword(s):  
Allele Frequency ◽  
Western Corn Rootworm ◽  
Allele Frequencies ◽  
Chromosome 8 ◽  
Corn Belt ◽  
Corn Rootworm ◽  
Resistance Allele ◽  
Response To Selection ◽  
The Us ◽  
Causal Allele

Abstract Following the discovery of western corn rootworm (WCR; Diabrotica virgifera virgifera) populations resistant to the Bacillus thuringiensis (Bt) protein Cry3Bb1, resistance was genetically mapped to a single locus on WCR chromosome 8 and linked SNP markers were shown to correlate with the frequency of resistance among field-collected populations from the US Corn Belt. The purpose of this paper is to further investigate the relationship between one of these resistance-linked markers and the causal resistance locus. Using data from laboratory bioassays and field experiments, we show that one allele of the resistance-linked marker increased in frequency in response to selection, but was not perfectly linked to the causal resistance allele. By coupling the response to selection data with a genetic model of the linkage between the marker and the causal allele, we developed a model that allowed marker allele frequencies to be mapped to causal allele frequencies. We then used this model to estimate the resistance allele frequency distribution in the US Corn Belt based on collections from 40 populations. These estimates suggest that chromosome 8 Cry3Bb1 resistance allele frequency was generally low (<10%) for 65% of the landscape, though an estimated 13% of landscape has relatively high (>25%) resistance allele frequency.

scholarly journals Resistance to Bt Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae) in the U.S. Corn Belt

2013 ◽  
Vol 4 (3) ◽  
pp. 1-6 ◽  
Author(s):  
Eileen M. Cullen ◽  
Michael E. Gray ◽  
Aaron J. Gassmann ◽  
Bruce E. Hibbard
Keyword(s):  
Western Corn Rootworm ◽  
Corn Belt ◽  
Bt Corn ◽  
Corn Rootworm ◽  
The U.S
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