The Georgia Agricultural Experiment Station
College of Agricultural and Environmental Sciences
The University of Georgia

2001 Corn Performance Tests
Research Report Number 675
November 2001

Insect Screening Results

Evaluation of Corn Hybrids for Resistance to Insects

N. W. Widstrom and B.G. Rector

Environmental conditions in Georgia during the 2001 growing season were favorable for buildup of insect populations large enough to cause damage to corn. Generally, this damage is greatest in late-planted corn left in the field for an extended period past maturity.

It is recommended that hybrids resistant to insects be planted. These hybrids are presently the only economical means, in late plantings, for the reduction of damage by corn earworm, fall armyworm, maize weevil, and pink scavenger caterpillar. Consult your local county agent and/or extension entomologist for additional control recommendations for other insects.

Percent yield losses attributable to all insects for individual hybrids varied from 0.7% to 6.0% and are reflected by VG, G, F, P, and VP ratings in the tables. Hybrids in the tests sustained average yield losses of 2.1% and 3.1% in the full and mid-season, and short-season hybrid tests, respectively. The mean level of overall yield loss for all tests was 2.7%. Of the total loss, about 37% was attributable to ear injury by the corn earworm, 53% to the pink scavenger caterpillar, and 10% to the maize weevil. Losses to the pink scavenger caterpillar and maize weevil are based on damage by multiple generations of these insects as the corn dries in the field. Timely harvest will substantially reduce losses to these two insects.

>Evaluations for resistance to corn earworm and fall armyworm, maize weevil, and pink scavenger caterpillar are given for hybrids in the tables following. Lettered ratings refer only to relative resistance to insects and are not indicative of yield. Thus, a hybrid rated poor for resistance to insects might possibly be among the highest yielders and vice-versa. See the yield data in other tables for this information.

Husk tightness ratings were assigned using a scale of 1 to 5, in which 1 = very loose and 5 = very tight. No average rating was less than 2.0 or greater than 4.0; therefore, only loose, medium, and tight ratings are given in the tables.

Both the hybrid tests (full and mid-season, and short-season) were planted April 26, 2001. Plantings were delayed in 2001 due to dry field conditions during March and April. Plots were thinned to 20,000 plants per acre. Ratings for overall insect damage were completed during September.

Data for this section were compiled by J. M. Cook, J. C. Mullis, C. A. Pearl, Brad Arrington, and Heather Roberts of the United States Department of Agriculture, Crop Genetics and Breeding Research Unit, and Georgia Coastal Plain Experiment Station, Tifton, Georgia.

Tifton, Georgia:
Short-Season Corn Hybrids, 2001
Evaluations for Resistance to Insects and Other Traits

Tifton, Georgia:
Full and Mid-Season Corn Hybrids, 2001
Evaluations for Resistance to Insects and Other Traits

Table of Contents