The use of high volatile esters formulations of 2,4-D and 2,4,5-T, the alcohol fraction of which contains five or fewer carbons, shall be prohibited in the counties of Harrison, Mills, Lee, Muscatine and that part of Pottawattamie county west of Range 41 West of the 5th P.M. to beCorne effective upon filing.
Iowa Admin. Code r. 21-45.27