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Progress Report 12 May,. 1953
SOIL TREATMENT FOR CORN ROOTWORM CONTROL
By J. G. Rodriguez  I
Corn rootworms have occurred in Kentucky in sucbsian unpre#
dictable manner that the control problem has been difficult to approach.
Observations incpast years have shown that the most frequently attacked »
areas occur on bottomlands. Infestations occur on upland corn—growing
areas less frequently; in 1950, however, infestations of the Southern
corn rootworm were widespread over many upland fields and much re-
planting had to be done as a result of heavy damage, or total loss of first ·
plantings.
Investigations in progress since 1950 have been directed to- ·
wards control of Southern corn rootworms by means of soil insecticide
spray applications. During this time only two experiments have been
located on siiies where rootworms have occurred. Because these infesta-
tions cannot Abe predicted, a thorough evaluation of insecticide toxicity
on Southern corn rootworms has not been made. Nevertheless, it has
been possible to study the effect of certain chlorinated hydrocarbons, as
_ soil insecticides, on the corn plant as they have affected growth and yield.
This progress report is a summation of the work up to the present time.
1950 TESTS
The results of a test conducted near Bardwell, Kentucky on
Mississippi River bottom land are shown on Table 1. Six acres of a
field planted to Kentucky 203 were sectioned into plots which were . _
arranged in randomized blocks; the insecticides were applied in bands
over the planted row with a tractor mounted weed—type spray boom 3 days
after the corn was planted. The Southern corn rootworm infestation was
relatively light. Under these conditions aldrin gave somewhat better
protection than all other materials; it produced the highest yield, 76.5
bushels per acre, as compared to 60., 1 for the check plots. Aldrin and
. chlordane harvest yields were significantly higher than the yields of
dieldrin and the untreated check.
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j   This work was aided by a grant made by the Julius Hyman and
V _ Company Division of the Shell Chemical Corporation
S  -
Kentucky Agricultural Experiment Station
University of Kentucky
Lexington