22 ANNUAL REPORTS OF DEPARTMENT <»I AGRICULTURE, 1952 
Several Insecticides Control Cabbage Looper 
Studies of the ut ility of I )DT and other insect icides for the control 
of cabbage caterpillars in previous year.- have showed that a dust 
containing 3 percent of DDT is effective against most of the species 
attacking cabbage in the South. Use of DDT for t hi- purpose during 
the early stage of plant growth is now recommended and ha- usually 
given satisfactory results when properly applied. Reports were re- 
ceived from several growers in South Carolina during the fall of 1951 
that DDT was not giving adequate protection against the cabbage 
looper in commercial plantings of cabbage. Field plot tests to cheek 
these reports showed that dusts containing 5 percent of toxaphene or 
TDE were superior to a DDT dust of equal strength against a well- 
advanced infestation of the cabbage looper. This was the first time 
that DDT proved inferior to any other insect ieide in the control of 
the cabbage looper in experimental tests in the South. Further ob- 
servations will be made to determine whether or not this may be an 
indication that the insect has developed some degree of resistance to 
DDT following its widespread use on cabbage in recent years. Since 
many cabbage growers obtained a satisfactory control of the cabbage 
looper with DDT, it is believed that other factors also were involved. 
Complications in Control of Aphids on Cabbage 
The cabbage aphid was more abundant in the spring of 1951 than 
at any previous time in the past 20 years and caused serious damage 
to many commercial plantings of cabbage and related crops. Exten- 
sive observations made on 1 ( .) farms in South Carolina showed that 
growers used parathion, TEPP, BHC, or nicotine to combat this 
aphid. Parathion was the chief material used and gave an excellent 
initial kill when properly applied but there was a rapid reinfestation 
when parathion or TEPP were applied. A nicotine dust gave varia- 
ble and unsatisfactory results. There were strong indications that 
the unusually severe infestations of the cabbage aphid were due to the 
destruction of insect enemies of the aphid by early applications of 
parathion. 
In field experiments for the eontrol of aphids on cole crops in South 
Carolina, parathion proved superior to nicotine sulfate in the control 
of the turnip aphid on young cabbage. An intermediate degree of 
control of this aphid was obtained in the experiments in which lindane 
Effective Controls for Pea Aphids ami Pea \\ cevils Developed 
Large-scale field experiments were conducted during 1951 in co- 
operation with the Wisconsin Agricultural Experiment Station to 
evaluate DDT and other new insecticides for pea-aphid control. 
These demonstrated thai dusts containing 1 percent of parathion, 
TEPP, or rotenone, or 5 percent of DDT were very effective for the 
control of this pest under the humid conditions existing in the ( Jentral 
;iikI Eastern States. Equally good results were obtained with -prays 
containing equivalent strengths of these insecticides. These mate- 
rials have been widely adopted for use by the growers. Nearly 6i 
