Uptake, Translocation, and Metabolism of Amicarbazone In Annual Bluegrass, Creeping Bentgrass, and Tall Fescue.

Amicarbazone selectively controls annual bluegrass in cool-season turfgrasses, which may be attributed to differential absorption and translocation among species. To test this hypothesis, research was conducted to evaluate absorption and translocation of ¹⁴C-amicarbazone in annual bluegrass, creeping bentgrass, and tall fescue. Foliar absorption of annual bluegrass was greater than creeping bentgrass and tall fescue at all harvest timings from 3 to 72 h after treatment.  The majority of foliar-applied ¹⁴C-amicarbazone was absorbed by annual bluegrass at 3 h after treatment, with an accumulation in the plant of 57% of the total radioactivity applied. At 72 h after treatment, annual bluegrass translocated a greater percentage of foliar-absorbed ¹⁴C to roots than creeping bentgrass and tall fescue.  Annual bluegrass and creeping bentgrass translocated greater percentages (73 and 70%, respectively) of root-absorbed ¹⁴C to shoots than tall fescue (55%). After 72 h, annual bluegrass accumulated more ¹⁴C in shoots and total plant per dry weight as compared to creeping bentgrass and tall fescue. These results indicate that amicarbazone is a systemic herbicide and readily absorbed by shoots and roots of these grasses. Annual bluegrass showed greater foliar and root absorption and subsequent translocation than creeping bentgrass and tall fescue, which may be attributed to amicarbazone selectivity for annual bluegrass control in these turf species.