40 ANNUAL REPORTS OF DEPARTMENT OF AGBICUI/TUBB, 1953 
.:t 0.75-percent, or endrin at 0.2-percent strength in emulsions con- 
taining mineral oil grave tin* mosj effective earworm control. TDK 
was less certain in emulsions hut was satisfactory in oil solutions. 
Tests to determine the absence of harmful residues are i y before 
heptachlor, dieldrin, or endrin can be recommended. 
Resistance of Corn to Corn Earworm 
Nine of ilic most corn earworm-resistant new hybrid sweet corns 
tested in l^-^J. had inbred LTB as one parent. This inbred in cr< 
produces a long, slender ear such as is desired by the southern fresh 
corn shipper. No other hybrids from outside sources showed much 
promise. Severa] sweei corn crosses from currenl breeding material 
continued to be resistant Crosses containing inbred 20 were especially 
good. This inbred is perhaps the best yellow sweet corn found to 
date for breeding for corn earworm resistance. 
Twenty of the most promising dent corn hybrids and two open- 
pollinated varict ies were tested at t he Mississippi Agricultural Experi- 
ment Station, State College, Miss., and at five of its branch -tat ion-. 
Ten of the .-train- showed some resistance. At Poplarville, the hy- 
brids Ga, 281 and Mi>-. 2115 proved highly resistant to both the 
earworm and rice weevil. Dixie 18, Miss. 21 17. Miss. 1216, ( Joker 811, 
Miss. L212, Dixie 11. and La. 521 were only lightly damaged !•; 
corn earworm and moderately damaged by the rice weevil. Dixie l v 
was resistant to the earworm at State College and Verona, Dixie 11. 
Coker 811, and Funk G875W were moderately resistant at Verona. 
Cokei- Ml had slightly more damage than Dixie 18 at State College 
bul showed some resistance to the earworm. along with Dixie 11 and 
Funk G875W. 
The resistance work was done in cooperation with plant breeders of 
the Bureau of Plant [ndustry, Soils, and A^gricultural Engineering 
and the agricultural experiment stations of Dlinois, Indiana. Texas, 
Iowa, Ohio, Mississippi, and South Carolina. 
European Corn Borer Research 
(lorn strains tested for corn borer resistance 
At the Bureau's Toledo, Ohio, station a uniform single cross com- 
parison of parent lines furnished by agricultural experiment stations 
in the northern State- of the North-Central region showed Lnbreds 
Michigan L334 and Minnesota A 198 to have a good degree of resistance 
to first brood infestat ion. 
Possibilities of combining in i bo same line resistance to both 
northern corn root worm and the European corn borer were studied al 
Ankeiiv. [owa, It was found that HI I. B2, and 38 11 and related 
lines were outstanding in contributing rootworm resistam 
The resistance investigations were conducted in cooperation with 
corn breeders in the Bureau of Plant [ndust ry, Soils, and V^gricult ural 
Engineering and the Stale agricultural experiment stations. 
New Insecticide* effective againsl corn borer 
Field tests of five new insecticides, each applied at the rate of L0 
gallons of spray per acre, showed that two of them were equalh 
outstanding in effectiveness and gave as high control as DDT. the 
currently recommended insecticide for corn borer control. These 
