Purdue University
Agricultural Extension Service
Department of Botany and Plant Pathology

Mimeo BP-57, Revised
March 1954 (Im)

Weeding Soybeans with Dinitro.
Oliver C . Lee
Numerous chemicals have been tried experimentally for the control of
weeds in soybeans. Of these, Dinitro-ortho-sec-butyl-phenol, called
"dinitro" for short, has given promising results. However, it is still
in the experimental stage and can only be recommended for trial use.The
following statements may be used as a guide for the use of dinitro in
field trials. Such trials should be limited to portions of fields that
are extremely weedy where cultural practices will not control the weeds
satisfactorily.

When to Apply.
Dinitro is applied as a pre-emergence treatment. The chemical should
be applied preferably just before the soybeans emerge. However, satis-
factory results can be expected if applied at planting time. The chemi-
cal will kill soybeans if applied after they have emerged. Best results
can be expected on heavy soils and when moisture and growing conditions
are favorable for rapid germination of weed seeds. This treatment is not
recommended on sandy soils.

How Much to Apply.
Two and 2/3 gallons of the commercial preparation of dinitro in 20
gallons of water per acre is suggested when the entire area is sprayed.
When applied as a 10-inch band, over the row, 3 quarts of the material
in 5 gallons of water per acre is suggested when soybeans are planted
in 40-inch rows.

How to Apply.
For over-all application, an ordinary weed type sprayer with a
straight boom, held approximately 13 inches from the ground is satisfac-
tory. If only over-the-row applications are made with a weed sprayer,
every other nozzle should be closed and the boom lowered to apply a 10-
inch band over the row. Special equipment may be made to attach to the
planter, such as a single nozzle attached to the planter shoe, applying
a 10-inch band over the row.

Results to Expect.
The rate of dinitro recommended may reduce the stand of soybeans
slightly. Plants emerging in soil pockets where the chemical has accumu-
lated may be killed. Generally this will not affect yields. The treat-
ment is effective against all annual weeds including grasses except
giant foxtail. However, it will not control Canada thistle, Johnson-
grass, perennial morning glory and other deep-rooted perennial weeds.