Of these methods of selectivity, metabolism is most important. The herbicide is detoxified by hydroxylation and conjugation with glucose. Imidazolinone herbicides are selective in legume crops and the herbicide controls both dicot and monocot weeds. Lateral roots can also be stunted, giving the roots a bottle brush-like appearance. Imidazolinone activity increases when temperatures are cool.
Rainfall enhances herbicide activity.
Imidazolinone tolerance in corn is due to a single semidominant allele. To produce IT corn inbreds, corn with the IT allele is backcrossed to a recurrent inbred parent. The inbred is then selfed to derive a homozygous IT inbred. IT hybrids have the gene from one inbred parent, while IR hybrids have the tolerant gene from both inbred parents. There is a potential for linkage of the IT allele to undesirable alleles which may decrease hybrid performance.