I know this is an older thread but I found the law.
U.S. Code § 136j - Unlawful acts
(2)It shall be unlawful for any
person—
(G)
to use any registered pesticide in a manner inconsistent with its labeling;
7 U.S. Code § 136 - Definitions
(ee)To use any registered pesticide in a manner inconsistent with its labeling
The term “
to use any registered pesticide in a manner inconsistent with its labeling” means to use any registered pesticide in a manner not permitted by the
labeling, except that the term shall not include (1) applying a pesticide at any dosage, concentration, or frequency less than that specified on the
labeling unless the
labeling specifically prohibits deviation from the specified dosage, concentration, or frequency, (2) applying a pesticide against any target
pest not specified on the
labeling if the application is to the crop,
animal, or site specified on the
labeling, unless the
Administrator has required that the
labeling specifically
state that the pesticide may be used only for the
pests specified on the
labeling after the
Administrator has determined that the use of the pesticide against other
pests would cause an unreasonable adverse effect on the
environment, (3) employing any method of application not prohibited by the
labeling unless the
labeling specifically
states that the product may be applied only by the methods specified on the
labeling, (4) mixing a pesticide or pesticides with a fertilizer when such mixture is not prohibited by the
labeling, (5) any use of a pesticide in conformance with section
136c,
136p, or
136v of this title, or (6) any use of a pesticide in a manner that the
Administrator determines to be consistent with the purposes of this subchapter. After March 31, 1979, the term shall not include the use of a pesticide for agricultural or forestry purposes at a dilution less than
label dosage unless before or after that date the
Administrator issues a regulation or advisory opinion consistent with the study provided for in section 27(b) of the
Federal Pesticide Act of 1978, which regulation or advisory opinion specifically requires the use of definite amounts of dilution.