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In this Issue:

Insect Pest Overview-2003

Harvesting and Storing Pumpkins

Biotech Foods Found to be Safe

2003 Snap Bean Insecticide Results
Vol 5 No. 9   October 10, 2003

Control of European Corn Borer in Minnesota Snap Beans, 2003

E.C. Burkness, R.L. Koch & W.D. Hutchison, Dept. of Entomology, Univ. of Minn.

'Hystyle' was planted June 2 at the University of Minnesota Agricultural Experiment Station at Rosemount, MN. Plots were 4 rows wide with an untreated skip row between plots and 25 ft (7.6 m) long. Rows were planted on 30 in (0.8 m) centers with 10 ft (3.04 m) alleys separating replicates. Treatments were arranged in a randomized complete block design with 4 replicates. Applications were made with a CO2 pressurized backpack sprayer using a 10 ft boom with 6 nozzles each fitted with an XR-Teejet 8002 flat fan nozzle with no screen. The sprayer was calibrated to deliver 20 gpa (187.04 l/ha) at 35 psi (242 kPa). On July 16 and 21, at blossom and pin-bean (beans</=1 inch) growth stages respectively, 5 ft (1.02 m) of consecutive row from one of the 2 middle rows of each plot were infested with "40 neonate larvae per plant using a bazooka applicator. A total of 3 sprays were applied on July 15, 18, and 23. All treatments were harvested and evaluated July 29 by selecting 5 consecutive plants from the center of the 5 ft of row with infested plants. For each plant, data were recorded for total European corn borer (ECB) larvae (in the pods or stem), damaged pods, total pods, and yield. The percentage of stems with feeding damage for each set of 5 plants was also recorded.

For total ECB and ECB in the pods, all treatments provided a significant reduction compared with the untreated check. The number of damaged pods and percentage of stems damaged were also significantly less compared with the untreated check for all treatments. No significant differences were found for total pods or yield for any treatment compared with the untreated check (see Table 1, below). No phytotoxicity was observed among treatments.

Table 1: Evaluation of insecticides for control of European corn borer in Minnesota snap beans, 2003
  Average/5 consecutive plants
Treatment/formulation Rate (lb AI/acre) Total ECB larvae1 ECB larvae in pods Damaged pods Total pods %Stems damaged Yield (lbs.)
Capture 2EC 0.040 0.00 b 0.00 b 0.00 b 65.50 0 b 0.56
Warrior ICS 0.025 0.00 b 0.00 b 0.00 b 65.25 0 b 0.64
SpinTor 2SC 0.094 0.00 b 0.00 b 1.00 b 72.00 5 b 0.72
Entrust 80WP 0.094 0.25 b 0.25 b 0.50 b 71.50 0 b 0.63
Untreated Check --- 5.50 a 2.50 a 7.50 a 78.00 55 a 0.68
          NS   NS
Means within columns followed by the same letter are not significantly different (P > 0.05), Least significant difference test (LSD).
NS=not significant ANOVA. Stem damage data were transformed using the arcsine transformation to obtain mean separations using LSD (P=0.05); untransformed means are presented.
1Total ECB larvae includes all larval instars found in both the stem and pods

Co-Editors: Bill Hutchison, Department of Entomology, University of Minnesota, hutch002@tc.umn.edu
Jeanne Ciborowski, IPM Program, Minnesota Department of Agriculture, jeanne.ciborowski@state.mn.us
Production Editor: Suzanne Wold Burkness, Research Fellow, Department of Entomology, University of Minnesota, woldx018@tc.umn.edu

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Last Revised October 9, 2003.
The University, including the Minnesota Extension Service, is an equal opportunity educator and employer. ©1999-2003 Minnesota Extension Service, University of Minnesota. All rights reserved. Contact copyright@extension.umn.edu for information on reproduction or use of this material.