scholarly journals Larval mortality and development for rotation-resistant and rotation-susceptible populations of western corn rootworm on Bt corn

2014 ◽  
Vol 139 (1-2) ◽  
pp. 46-54 ◽  
Author(s):  
N. A. Tinsley ◽  
J. L. Spencer ◽  
R. E. Estes ◽  
J. R. Prasifka ◽  
P. M. Schrader ◽  
...  
2013 ◽  
Vol 4 (3) ◽  
pp. 1-6 ◽  
Author(s):  
Eileen M. Cullen ◽  
Michael E. Gray ◽  
Aaron J. Gassmann ◽  
Bruce E. Hibbard

2015 ◽  
Vol 108 (2) ◽  
pp. 742-751 ◽  
Author(s):  
D. S. Wangila ◽  
A. J. Gassmann ◽  
J. L. Petzold-Maxwell ◽  
B. W. French ◽  
L. J. Meinke

2003 ◽  
Vol 96 (6) ◽  
pp. 1855-1863 ◽  
Author(s):  
Xuguo Zhou ◽  
Michael E. Scharf ◽  
Lance J. Meinke ◽  
Laurence D. Chandler ◽  
Blair D. Siegfried

Author(s):  
Aaron J. Gassmann ◽  
Erin W. Hodgson

2017 ◽  
Vol 9 (3) ◽  
pp. 27-38
Author(s):  
A. Andow David ◽  
J. Wright Robert ◽  
W. Hodgson Erin ◽  
E. Hunt Thomas ◽  
R. Ostlie Kenneth

2005 ◽  
Vol 95 (5) ◽  
pp. 473-482 ◽  
Author(s):  
S. Toepfer ◽  
C. Gueldenzoph ◽  
R.-U. Ehlers ◽  
U. Kuhlmann

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.


2020 ◽  
Vol 113 (4) ◽  
pp. 1839-1849
Author(s):  
Coy R St. Clair ◽  
Graham P Head ◽  
Aaron J Gassmann

Abstract Transgenic corn expressing insecticidal proteins derived from the bacterium Bacillus thuringiensis (Bt) is an important pest management tool. Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a key pest of corn in the midwestern United States that has developed field-evolved resistance to all available Bt traits. The first Bt trait to be commercialized for management of rootworm was Cry3Bb1 in 2003, and field-evolved resistance appeared in 2009. In this study, we examined fields in counties where greater-than-expected injury to Cry3 (Cry3Bb1 or mCry3A) corn roots (>1 node) had previously been reported (problem counties) and counties where injury had not been reported (non-problem counties). Four to eight fields were sampled per county in 2015, 2016, and 2017 to quantify rootworm abundance, root injury, Cry3Bb1resistance, and rootworm management strategies. Rootworm abundance, root injury, and resistance to Cry3Bb1 did not differ between county types. Management tactics differed between county types, with problem counties growing more corn, using more soil insecticide, and growing more Cry34/35Ab1 corn. Additionally, a comparison of root injury to Bt and non-Bt corn within fields indicated that farmers derived an economic benefit from planting Bt corn to manage corn rootworm. Our results suggest that rootworm populations are similar between problem and non-problem counties in Iowa due to similar levels of selection pressure on Cry3 corn, but problem county fields have applied more management tactics due to previous rootworm issues in the area.


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