On-Farm Efficacy of Aerially Applied Bacillus thuringiensis for European Corn Borer (Lepidoptera: Pyralidae) and Corn Earworm (Lepidoptera: Noctuidae) Control in Sweet Corn

1995 ◽  
Vol 88 (2) ◽  
pp. 380-386 ◽  
Author(s):  
David W. Bartels ◽  
William D. Hutchison
Keyword(s):  
Bacillus Thuringiensis ◽  
European Corn Borer ◽  
Sweet Corn ◽  
Corn Earworm ◽  
Corn Borer ◽  
Lepidoptera Pyralidae ◽  
On Farm ◽  
Lepidoptera Noctuidae

Effect of Bacillus thuringiensis Application Interval on European Corn Borer (Lepidoptera: Pyralidae) Control in Sweet Corn

1995 ◽  
Vol 30 (3) ◽  
pp. 374-389 ◽  
Author(s):  
David W. Bartels ◽  
William D. Hutchison ◽  
Vincent A. Fritz ◽  
George R. Klacan
Keyword(s):  
Bacillus Thuringiensis ◽  
European Corn Borer ◽  
Sweet Corn ◽  
Natural Populations ◽  
Corn Borer ◽  
First Instar ◽  
Additional Control ◽  
Dependent Variables ◽  
Lepidoptera Pyralidae ◽  
Low Rate

Ground-applied treatments of two commercial Bacillus thuringiensis subsp. kurstaki formulations (MVP and Dipel ES) and tank-mixes with a pyrethroid (Ambush 2E) were evaluated for control of European corn borer, Ostrinia nubilalis (Hübner), larvae in sweet corn. Treatments were applied at average intervals of 3.4, 5, 7, and 10 days to determine field persistence. Manual infestations of first-instar O. nubilalis were used to augment natural populations. During both years, there were no significant interactions between application interval and treatment for all dependent variables tested, including late instars per ear, percent marketability, yield, and predator density. Regardless of application interval, MVP provided greater larval control than Dipel ES. However, the decline in efficacy of the encapsulated MVP formulation occurred at the same rate as that of the non-encapsulated Dipel ES formulation over the 3.4 to 10-d intervals. Tank-mixes of B. thuringiensis + low-rate permethrin provided no additional control compared with low-rate permethrin alone. Given the infestation levels present in this test, neither B. thuringiensis formulation provided control sufficient to maintain current processor standards of 5–10% infested ears at harvest.

scholarly journals Optimum Timing of an Application of Corn Oil and Bacillus thuringiensis to Control Lepidopteran Pests in Sweet Corn

2004 ◽  
Vol 14 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Rosalind Cook ◽  
Anne Carter ◽  
Pamela Westgate ◽  
Ruth Hazzard
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Zea ◽  
European Corn Borer ◽  
Sweet Corn ◽  
Corn Oil ◽  
Corn Earworm ◽  
Larval Feeding ◽  
Corn Borer ◽  
Late Planting ◽  
All Treatment

Corn oil and Bacillus thuringiensis ssp. kurstaki (Bt) applied directly into the silk channel of a corn ear has been shown to be an effective pesticide against corn earworm, Helicoverpa zea (CEW), and european corn borer, Ostrinia nubilalis (ECB). Field studies were conducted in 2000 and 2001 to determine the influence of application timing on ear quality at harvest. Two blocks of corn were planted during each year to observe treatment effects under varying populations of the two insect species. The treatment consisted of 0.5 mL (0.017 floz) of food grade corn oil containing a suspension of Bt at 0.08 g (0.003 oz) a.i. per ear applied directly into the silk channel at the husk opening. One treatment application was made on each silk day 3 through 11 from first silk; silk day 1 was the first day that 50% or more of ears had 2.5 cm (1 inch) of silk protruding from the husk. One treatment did not receive the oil + Bt suspension. All ears were harvested at milk stage, on silk day 25. The number of CEW larvae in treated ears increased with later application days in 2000, but not in 2001. Damage from larval feeding was mainly found near the tip of the ear, and damage ratings were lower compared to untreated ears for all treatment days for both plantings in 2000, and through application day 8 in the late planting of 2001. ECB larvae were reduced for all treatment days in both plantings in 2000 and the late planting of 2001. The percentage of ears rated as marketable (i.e., free of feeding damage) ranged from 71% to 100% in treated plots compared to 30% to 77% in the untreated plots. There was a linear decrease in marketability with later application days in two of the four plantings. The greatest decrease in marketability was after application day 7. Because the oil application affects kernel development at the tip, the length of ear with under-developed kernels, or cone tip, was measured. The number of ears with cone tip decreased linearly with the later application days in all plantings. There was 10% conetip or less after day 7 in 2000 and day 6 in 2001. The best combination of effective insect control resulting in the highest rates of marketable ears with the least degree of cone tip was achieved in this experiment by application of oil + Bt suspension on day 7. Year to year variation in the environment would suggest a range from day 6 to 8.

scholarly journals CONTROL OF CORN EARWORM AND EUROPEAN CORN BORER ON SWEET CORN, 1998

1999 ◽  
Vol 24 (1) ◽  
Author(s):  
P. K. O'Rourke ◽  
E. C. Burkness ◽  
W. D. Hutchison
Keyword(s):  
European Corn Borer ◽  
Sweet Corn ◽  
Corn Earworm ◽  
Corn Borer

scholarly journals Evaluation of Efficacy of Selected Conventional and Experimental Insecticides and Bt Hybrids for Control of Corn Earworm and European Corn Borer on Sweet Corn, 1997

1998 ◽  
Vol 23 (1) ◽  
pp. 99-100
Author(s):  
J. T. Shaw ◽  
R. Weinzierl ◽  
J. W. Finger
Keyword(s):  
European Corn Borer ◽  
Sweet Corn ◽  
Corn Earworm ◽  
Compressed Air ◽  
Hollow Cone ◽  
Corn Hybrids ◽  
Corn Borer ◽  
Chemical Treatments ◽  
Untreated Check ◽  
High Clearance

Abstract The tests were arranged in a RCB design with four replications. Each plot consisted of four rows, each being 30 inches wide and 50 ft long. Thirty-foot-wide alleys were established between the four replications. Insecticides were applied to the middle two rows of each plot, leaving two untreated rows between adjoining plots. Twelve insecticide treatments were compared with two Br-sweet corn hybrids (Heritage Bt and Bonus Bt) and their non-Bt isolines to two untreated controls. The 12 chemical treatments and the two untreated checks were planted with the Silver King variety sweet corn. Two untreated check plots were included in each replication and were averaged for the ANOVA. Treatments were applied very four to five days beginning on 8 Aug at 8% silk. All insecticide treatments were applied with a modified John Deere 6000 high-clearance vehicle (HCV) with a rear-mounted boom. Six Conejet (TX VS-8) hollow-cone nozzles (three per row) were calibrated to deliver 30.1 gpa at 40 psi and a speed of 2.5 mph, utilizing a compressed air system. Four nozzles (two per row) were attached to drops and directed the spray towards the ear zone area, a third nozzle (one per row) was mounted directly over the row with the spray being directed into the whorl (tassel) area.

DOSE–MORTALITY RESPONSE OF EUROPEAN CORN BORER (LEPIDOPTERA: PYRALIDAE) THIRD-INSTAR LARVAE TO SELECTED INSECTICIDES

1993 ◽  
Vol 125 (6) ◽  
pp. 1137-1139 ◽  
Author(s):  
William D. Hutchison
Keyword(s):  
United States ◽  
Ostrinia Nubilalis ◽  
European Corn Borer ◽  
Sweet Corn ◽  
Corn Borer ◽  
Mortality Response ◽  
Ca 50 ◽  
Lepidoptera Pyralidae ◽  
Economic Pest ◽  
Insecticide Control

The European corn borer, Ostrinia nubilalis Hübner, continues to be a consistent economic pest of field and sweet corn (Zea mays L.) in the upper midwestem United States. In Minnesota alone, O. nubilalis control costs and losses to sweet corn (ca. 50 630 ha) exceed $5,000,000 annually (Noetzel et al. 1985). Despite recent efforts to implement alternatives (Lewis and Bing 1991; Prokrym et al. 1992; Bartels and Hutchison 1993; Bolin et al. 1993), insecticide control continues to play a central role in O. nubilalis management programs.

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