Wireworm Insecticide Evaluation 1992

Keith J. Jarvi
University of Nebraska-Lincoln
Northeast Research and Extension Center
Concord, NE 68728

Granular soil insecticides were tested for the control of wireworms Melanotus depressus (Melsh.), on field corn Zea mays L. The location of the field was just north and west of Schuyler in Colfax Co., NE.

Treatments were Counter 15G (American Cyanamid) in--furrow at 8 oz /1000 ft of row, Force 1.5G (ICI) (clay granules) T-banded and in-furrow at 8 oz/1000 ft of row, Aztec 2.1G (Miles) T-banded at 6.7 oz/1000 ft of row, Lorsban 15G (DowElanco) T-banded at 8 oz/1000 ft of row, and an untreated check.

The test plots were planted on May 7. The previous crop was wheat. Banded (7 inch T-band) and in-furrow planting time treatments were applied with a cone-belt distributor mounted on a 2 row John Deere Maxemerge equipped with incorporation tines. Treatments were applied no till into slots previously prepared with the landowner's planter. Soil moisture was adequate at planting. The variety of corn used was DeKalb 636 planted at a seeding rate of 16,600 seeds/acre on 30 inch rows.

The experimental design was a randomized complete block with four replications, each treatment two rows 50 ft long, with no border rows between treatments. Plant populations were taken in a randomly selected 30 ft area in each of the two rows. The results are given as number of live plants per 60 ft of row. Final plant stand count taken on July 10.

Wireworm pressure was extreme with the four untreated control plots averaging only 4.25 plants per 60 ft of row.

Table 1. Wireworm Control in Seedling Corn, Plant Population July 10, 1992
Insecticide	Rate/oz	Placement	Plant population 1000 ft
Counter 15G	8 oz	In-furrow	44.75 A
Force 1.5G	8 oz	In-furrow	36.25 B
Force 1.5G	8 oz	T-band	35.50 B
Aztec 2.1G	6.7 oz	T-band	31.50 BC
Lorsban 15G	8 oz	T-band	23.75 C
Untreated			4.25 D

LSD = 8.0476 (alpha = 0.05) Means with the same letter are not significantly different.