Foliar and Root Absorption and Translocation of Bispyribac-sodium in Cool-season Turfgrass

Abstract

Response of creeping bentgrass, annual bluegrass, and Kentucky bluegrass to foliar, soil, or foliar plus soil applications of bispyribac-sodium was evaluated in greenhouse studies. Soil-alone and foliar plus soil applications of bispyribac-sodium at 148 or 296 g ai/ha resulted in greater injury and shoot dry weight reduction of all species 28 d after treatment (DAT) compared to foliar-alone treatments. Creeping bentgrass was less injured than annual or Kentucky bluegrass regardless of application placement. Further studies evaluated foliar and root absorption and translocation of14C-bispyribac-sodium in creeping bentgrass, annual bluegrass, Kentucky bluegrass, and roughtstalk bluegrass. Foliar absorption into creeping bentgrass was less than that of other species at most harvest timings from 4 to 72 h after treatment. Annual and roughstalk bluegrass translocated greater amounts of foliar-absorbed14C to the crown and shoots compared to creeping bentgrass. Annual and roughstalk bluegrass accumulated approximately 47% more14C per dry weight of plant tissue than creeping bentgrass and 74% more than Kentucky bluegrass after 72 h in nutrient solution containing14C-bispyribac-sodium. Annual and roughstalk bluegrass translocated approximately 80% of root-absorbed14C to shoots, whereas creeping bentgrass and Kentucky bluegrass translocated slightly less (66% of absorbed for both species). These studies suggest that bispyribac-sodium is readily absorbed by roots and translocated to shoots which may contribute to its total activity within a plant. In addition, creeping bentgrass displayed lower amounts of foliar and root absorption and subsequent translocation than annual and roughstalk bluegrass which may contribute to greater bispyribac-sodium tolerance displayed by creeping bentgrass.

Methiozolin [5-(2,6-difluorobenzyl)oxymethyl-5-methyl-3,3(3-methylthiophen-2-yl)-1,2-isoxazoline], a new annual bluegrass (Poa annuaL.) herbicide for turfgrasses

“…Lycan and Hart showed that bispyribac‐sodium absorption and translocation was greater in root application than foliar application . Inhibitory activity was also greater with foliar and root administration than foliar only; however, the difference was small.…”

Trinexapac-Ethyl Influences Bispyribac-Sodium Absorption and Efficacy for Annual Bluegrass (Poa annua) Control in Creeping Bentgrass (Agrostis stolonifera)

“…This harvest timing was chosen on the basis of previous investigations with 14 Cbispyribac-sodium absorption by Lycan and Hart (2006b). Unabsorbed 14 C-bispyribac-sodium was removed by swirling the treated leaf in a 20-ml scintillation vial containing 2 ml of 10% methanol solution for approximately 45 s. Upon removal from vials, leaves were rinsed with 2 ml of 10% methanol washoff solution.…”

Growth Stage Influences Mesotrione Efficacy and Fate in Two Bluegrass (Poa) Species

“…Annual and Kentucky bluegrass have exhibited similar translocation of 14 C-primisulfuron-methyl, despite the differential tolerance levels to applications . Researchers have also noted greater translocation of radioactivity from 14 C-amicarbazone and 14 Cbispyribac-sodium in annual bluegrass compared to creeping bentgrass (Lycan and Hart 2006;Yu et al 2013). Results suggest that translocation patterns do not explain the selectivity of mesotrione in these bluegrass species.…”