BACILLUS THURINGIENSIS (BT) TRANSFORMED CORN PERFORMANCE AGAINST NATURAL AND ARTIFICIAL INFESTATIONS OF EUROPEAN CORN BORER, 1998

Two types of pregelatinized corn flour were used to produce granules containing Bacillus thuringiensis Berliner subsp. kurstaki and various additives for control of the European corn borer, Ostrinia nubilalis (Hübner), in the whorl of corn plants. Laboratory-reared larvae were applied to corn whorls in the greenhouse and field, and a high natural infestation occurred at one field site (Champaign). In the greenhouse and at all three field sites, five of these formulations were just as effective as Dipel 10G, a commercially available B. thuringiensis product, for control of European corn borer larvae. In all greenhouse studies and at one of the three field sites (Champaign), the dose of B. thuringiensis could be reduced by as much as 75% when a phagostimulant was added to flour granules without significant loss of corn borer control. The phagostimulant dose response was not observed at the other two field sites in which larval infestations were relatively low. Flour type had no significant effect on European corn borer control under greenhouse and field conditions. Greenhouse evaluations provided results significantly similar to results from two of the field sites indicating the usefulness of the technique. The data presented highlight the versatility and potential for using novel formulation techniques for enhancing the efficacy of B. thuringiensis.

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Mortality of Two Lepidopterans in Response to Selected Commercial Formulations of Bacillus thuringiensis Berliner2

Journal of Entomological Science ◽

10.18474/0749-8004-34.3.273 ◽

1999 ◽

Vol 34 (3) ◽

pp. 273-285

Author(s):

Richard L. Ridgway ◽

Robert R. Farrar

Keyword(s):

Bacillus Thuringiensis ◽

Helicoverpa Zea ◽

European Corn Borer ◽

Uv Light ◽

Field Studies ◽

Corn Earworm ◽

The Other ◽

Speed Of Kill ◽

Matrix Formulation ◽

Corn Borer

Five commercial granular formulations of Bacillus thuringiensis Berliner marketed for controlling the European corn borer, Ostrinia nubilalis (Hübner), were compared for insecticidal activity using treated discs of bean leaves. Three formulations, Dipel 10G®, Full-Bac ECBG™, and Strike BT®, were similar in terms of both mortality and speed of kill. A formulation containing a strain of B. thuringiensis developed by plasmid fusion, Condor G®, caused mortality similar to the other three formulations, but the speed of kill was slower. A fifth formulation containing a B. thuringiensis toxin produced by Pseudomonas fluorescens Migula as result of a gene transfer, M-Peril™, caused substantially less mortality than any of the other formulations. An experimental water dispersible formulation, based on a previously developed granular matrix formulation containing B. thuringiensis and a nutrient-based phagostimulant, caused significantly higher mortality of the European corn borer than a similar formulation without the phagostimulant. Simulated field studies were conducted to study the effects of the phagostimulant on feeding and protection of B. thuringiensis from ultraviolet (UV) light. Bean plants treated with B. thuringiensis and the phagostimulant were exposed to different UV regimes outdoors under canopies made of specialized acrylic plastics and then infested with larvae of the corn earworm, Helicoverpa zea (Boddie). A significant interaction between the UV regimes and the phagostimulant was found, indicating that the phagostimulant acted both as a feeding stimulant and as a UV protectant to enhance the activity of B. thuringiensis.

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Frequency of Resistance to Bacillus thuringiensis Toxin Cry1Ab in an Iowa Population of European Corn Borer (Lepidoptera: Crambidae)

Journal of Economic Entomology ◽

10.1603/0022-0493-93.1.26 ◽

2000 ◽

Vol 93 (1) ◽

pp. 26-30 ◽

Cited By ~ 75

Author(s):

D. A. Andow ◽

D. M. Olson ◽

R. L. Hellmich ◽

D. N. Alstad ◽

W. D. Hutchison

Keyword(s):

Bacillus Thuringiensis ◽

European Corn Borer ◽

Corn Borer

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Characterization of Chimeric Bacillus thuringiensis Vip3 Toxins

Applied and Environmental Microbiology ◽

10.1128/aem.02079-06 ◽

2006 ◽

Vol 73 (3) ◽

pp. 956-961 ◽

Cited By ~ 82

Author(s):

Jun Fang ◽

Xiaoli Xu ◽

Ping Wang ◽

Jian-Zhou Zhao ◽

Anthony M. Shelton ◽

...

Keyword(s):

Bacillus Thuringiensis ◽

Trichoplusia Ni ◽

European Corn Borer ◽

Insect Pest ◽

Chimeric Protein ◽

Fall Armyworm ◽

Terminal Region ◽

Cabbage Looper ◽

Cross Resistance ◽

Corn Borer

ABSTRACT Bacillus thuringiensis vegetative insecticidal proteins (Vip) are potential alternatives for B. thuringiensis endotoxins that are currently utilized in commercial transgenic insect-resistant crops. Screening a large number of B. thuringiensis isolates resulted in the cloning of vip3Ac1. Vip3Ac1 showed high insecticidal activity against the fall armyworm Spodoptera frugiperda and the cotton bollworm Helicoverpa zea but very low activity against the silkworm Bombyx mori. The host specificity of this Vip3 toxin was altered by sequence swapping with a previously identified toxin, Vip3Aa1. While both Vip3Aa1 and Vip3Ac1 showed no detectable toxicity against the European corn borer Ostrinia nubilalis, the chimeric protein Vip3AcAa, consisting of the N-terminal region of Vip3Ac1 and the C-terminal region of Vip3Aa1, became insecticidal to the European corn borer. In addition, the chimeric Vip3AcAa had increased toxicity to the fall armyworm. Furthermore, both Vip3Ac1 and Vip3AcAa are highly insecticidal to a strain of cabbage looper (Trichoplusia ni) that is highly resistant to the B. thuringiensis endotoxin Cry1Ac, thus experimentally showing for the first time the lack of cross-resistance between B. thuringiensis Cry1A proteins and Vip3A toxins. The results in this study demonstrated that vip3Ac1 and its chimeric vip3 genes can be excellent candidates for engineering a new generation of transgenic plants for insect pest control.

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