2002 Corn Performance Tests
The Georgia Agricultural Experiment Stations
College of Agricultural and Environmental Sciences
The University of Georgia

Research Report Number 684
October 2002

INSECT SCREENING RESULTS

Evaluation of Corn Hybrids for Resistance to Insects

N. W. Widstrom, B. Z. Guo, and B.G. Rector

Environmental conditions in Georgia during the 2002 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 plants, 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 1.2% to 7.3% and are reflected by VG, G, F, P, and VP ratings in the tables. Hybrids in the tests sustained average yield losses of 3.6% and 4.3% in the mid and full-season, and short-season hybrid tests, respectively. The mean level of overall yield loss for all tests was 4.0%. Of the total loss, about 34% was attributable to ear injury by the corn earworm, 58% to the pink scavenger caterpillar, and 8% 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 following tables. 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 greater than 4.0; therefore, only loose, medium, and tight ratings are given in the tables.

Both the hybrid tests (mid and full-season, and short-season) were planted April 24, 2002. Plantings were delayed in 2002 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 October.

Data for this section were compiled by J. M. Cook, J. C. Mullis, and Robert Giddens 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, 2002
Evaluations for Resistance to Insects and Other Traits
Overall Resistance
to Insect Injury2
Company or
Brand Name
Hybrid
Name
Husk Tightness1 Days to Anthesis 2002 2 or more
years
Zimmerman 1851W * T 59 VG -
Terral TV24R002 M 58 G -
Garst/AgriPro 8222IT M 55 G G
Agratech 721BtRR M 60 G -
Garst 8255RR L 58 G -
Terral TV2155Bt L 56 G -
Dyna-Gro X15617RR T 59 G -
Croplan Genetics 818Bt M 55 G -
Pioneer 33J57(YG) M 54 G -
Southland Seed Co. 02-201 L 53 G -
Dyna-Gro X15616RR M 60 G -
Pioneer 32D99 M 57 G -
Terral TV2160Bt M 58 F -
Pioneer 34B28 L 53 F P
Croplan Genetics G71CL/Bt L 52 F -
Terral TV2140RR T 60 F -
Croplan Genetics 721 L 54 F P
Agratech 733RR L 56 F -
Dyna-Gro 5518RR M 59 F F
Golden Acres 7997 L 54 F -
Monsanto Exp267 T 57 F -
Southland Seed Co. 02-202 L 59 F -
Terral T26BR10n L 56 F -
Dyna-Gro 5515 M 57 P P
Terral TV23R15n M 56 P -
Terral TV2140Xn1RR L 59 P -
Pioneer 32W86 M 54 P -
Southland Seed Co. 02-203 M 54 P -
Agratech 755RR M 54 P -
Pioneer 31G98 M 59 P P
Garst 8285RR M 61 P F
Garst 8366Bt M 57 P -
Dyna-Gro 5516RR M 57 P P
Southland Seed Co. 02-204 L 56 VP -
Garst 8348 M 56 VP -
Terral TV2140Xn2RR M 60 VP -
Southern States SS781CL L 56 VP -

* White hybrid.
1. L = loose husks, M = medium-tight husks, T = tight husks
2. Overall resistance to insect injury evaluations were made on the basis of total percent damage to the ear by one or more of the following insect categories: corn
    earworm and fall armyworm, maize weevil, and pink scavenger caterpillar. Ratings were made on a scale from very good to very poor, where VG = very good,
    G = good, F = fair, P = poor, and VP = very poor.





Tifton, Georgia:
Mid and Full-Season Corn Hybrids, 2002
Evaluations for Resistance to Insects and Other Traits
Overall Resistance
to Insect Injury2
Company or
Brand Name
Hybrid
Name
Husk Tightness1 Days to Anthesis 2002 2 or more
years
Greenwood 865 * T 65 VG -
DeKalb DKC68-70(YG) T 60 VG VG
DeKalb DKC69-70(YG) M 59 VG -
Pioneer 31R88 L 56 G -
Asgrow RX897RR M 58 G -
DeKalb DK687RR M 57 G G
Croplan Genetics 702 L 60 G G
Pioneer 32R25 M 60 G -
Greenwood 860 * T 63 G -
Agratech 905RR M 60 G -
Vigoro V61R36 T 61 G -
Agratech 803RR M 58 G -
Southern States SS842RR L 57 G -
Syngenta NX8901 M 56 G -
Garst/AgriPro 8288 M 55 G G
NK N91-R9 * L 59 F -
Croplan Genetics 827 M 61 F -
Southland Seed Co. 02-206 L 53 F -
Garst 8118RR M 61 F -
DeKalb DK 697 L 56 F F
Garst 8230IT L 56 F -
Golden Acres 7885 M 60 F -
Greenwood 780 L 60 F F
Croplan Genetics DS822RR L 61 F -
Golden Acres 8311 M 60 P F
Southland Seed Co. 02-205 L 57 P -
Golden Acres 8681FQ M 60 P P
NK N 83-N5 M 60 P P
Southland Seed Co. 02-207 L 60 VP -

* Full-season hybrid.
1. L = loose husks, M = medium-tight husks, T = tight husks
2. Overall resistance to insect injury evaluations were made on the basis of total percent damage to the ear by one or more of the following insect categories: corn
    earworm and fall armyworm, maize weevil, and pink scavenger caterpillar. Ratings were made on a scale from very good to very poor, where VG = very good,
    G = good, F = fair, P = poor, and VP = very poor.

Table of Contents