Black cutworm (Agrotis ipsilon Hufnagel) control in corn in northeast Nebraska

Soil insecticides and liquid treatments applied at planting time.

K. J. Jarvi and G. W. Echtenkamp
University of Nebraska Northeast Research and Extension Center
Concord, NE 68728

Introduction

The primary goal of this research was to compare the efficacy of planting time insecticides for cutworm control. No post-emergence treatments were included. It was not known which species of cutworm would be present. All specimens collected and identified were black cutworms.

Methods and Materials
Granular materials were applied at planting time on May 26, 1992 using a cone belt insecticide distributor attached to a John Deere Max-emerge 2 row planter. (See accompanying information.) The liquid material was broadcast immediately after planting with a backpack sprayer. Plot information is given in Table 1.

Plots were observed on June 12 and June 25. Only plant stand was evaluated.

Results and Discussion
Visual damage to untreated plots was light but evidence of cutting was present. Numerically, the cutting was less than 5%. This indicates that some damage may have occurred before the plants emerged. All treatments except Aztec 2.1G produced significantly higher final plant stands than the untreated check (Table 2). However, only the Ambush broadcast treatment was significantly better than the Aztec treatment.

Table 1. Plot Information
Location Wayne County, NE (6 miles south, 1 1/2 miles west of Wayne)
Variety Pioneer 3417 Date of planting: 26 May 1992
Planting rate 16,600 kernels per acre
Previous crop Alfalfa
Field preparation 1 1/2 qt 2,4-D, 1/2 pt Banvel to kill alfalfa, applied May 4, 1992
Plot Design Randomized Complete Block, 4 reps
Plot size Each rep 2 rows with 2 row borders between treatments, 50 ft long
Weather at planting 55 degrees F Wind: N 10-15 mph
Granular Applicator John Deere Max-emerge 2 row planter equipped with cone-belt insecticide distributor. Applied in a 7 inch band or in-furrow ahead of the press wheel followed by incorporation tines.
Spray Applicator 4 nozzle CO2 Backpack, T-jet 8002 nozzles. Broadcast spray width 5 ft, 25 psi, 19 gal/acre total spray volume. Applied after planting of plot, no incorporation. Band width application 15 inches.
Final evaluation Plant population per 60 ft of row (2 rows by 30 ft) taken June 25, 1992
Soil moisture Topsoil adequate to moist at planting.
Treatments Force 1.5G WF1535B (clay) 8 oz formulation/1000 ft of row, T-band
Force 1.5G WF1535B (clay) 8 oz formulation/1000 ft of row, In-furrow
Force 1.5G GFU524 (gypsum) 8 oz formulation/1000 ft of row, T-band
Ambush 2E .10 lb active ingredient/acre, broadcast
Ambush 2E .10 lb active ingredient/acre, banded
Aztec 2.1G 6.7 oz formulation/1000 ft of row, T-band
Lorsban 15G 8 oz formulation/1000 ft of row, T-band
Untreated Control

Table 2. Number of plants per 60 ft of row, June 25, 1992
Insecticide Plants   Plant population per acre (30" rows)
Ambush (br) 53.50 A 15530
Force IF 53.00 AB 15385
Force T-band 52.75 AB 15312
Force (gyp) 52.25 AB 15167
Ambush (band) 51.75 AB 15022
Lorsban 50.75 AB 14732
Aztec 48.50 BC 14078
Untreated 45.75 C 13280

Treatment means with the same letter are not significantly different. Alpha = 0.05 LSD = 4.93