Choice of Adjuvant with Halosulfuron Affects Purple Nutsedge Control and Nursery Crop Tolerance

Abstract

<jats:p>One-half (18 g·ha<jats:sup>-1</jats:sup> a.i.) and three-fourths (27 g·ha<jats:sup>-1</jats:sup> a.i.) rates of halosulfuron (Manage®, MON 12051) were combined with adjuvants and evaluated for effectiveness in controlling purple nutsedge (<jats:italic>Cyperus rotundus</jats:italic> L.) and for phytotoxic responses exhibited by two kinds of container-grown ornamental plants. Adjuvants included X-77®, Scoil®, Sun-It II®, Action “99”®, and Agri-Dex®. By 8 weeks after treatment (WAT), halosulfuron combined with X-77®, Agri-Dex®, or Action “99”® at the lower halosulfuron rate provided &lt;90% purple nutsedge suppression. In contrast, Sun-It II® provided 100% control when combined with the higher halosulfuron rate. Nutsedge control persisted into the following growing season and halosulfuron combined with either Scoil® or Sun-It II® provided &gt;97% suppression of nutsedge tuber production. Growth of liriope [<jats:italic>Liriope muscari</jats:italic> (Decne.) Bailey `Big Blue'] was not inhibited by Scoil® or Sun-It II® adjuvants in combination with the low rate of halosulfuron. However, regardless of the rate of halosulfuron or adjuvant used, initial foliar chlorosis was observed in both daylily (<jats:italic>Hemerocallis</jats:italic> sp. L. `Stella d'Oro') and liriope. All liriope receiving halosulfuron with X-77®, Scoil®, or Sun-It II® adjuvants recovered normal foliage by 8 WAT. By contrast, at 8 WAT some daylily still maintained a degree of foliar discoloration. In addition to chlorosis, all treatments reduced flower number in daylilies. The number of flower scapes produced by liriope was not affected by halosulfuron when in combination with either Sun-It II® or Scoil®. The high rate of halosulfuron combined with X-77® or Action “99”® improved control of purple nutsedge. However, this rate inhibited growth of both species, daylily flower numbers, and scape numbers of liriope, regardless of adjuvant. Chemical names used: halosulfuron (Manage®, MON 12051, methyl 5-{[(4,6-dimethyl-2-pyrimidinyl) amino] carbonyl-aminosulfonyl}-3-chloro-1-methyl-1-<jats:italic>H</jats:italic>-pyrozole-4-carboxylate); proprietary blends of 100% methylated seed oil (Scoil® and Sun-It II®); proprietary blend of 99% polyalkyleneoxide modified heptamethyl trisiloxane and nonionic surfactants (Action “99”®); alkylarylpolyoxyethylene, alkylpolyoxyethelene, fatty acids, glycols, dimethylpolysiloxane, and isopropanol (X-77®); proprietary blend of 83% paraffin-based petroleum oil, with 17% polyoxyethylate polyol fatty acid ester and polyol fatty ester as nonionic surfactants (Agri-Dex®)</jats:p>

Effect of Adjuvants on Herbicidal Activity and Selectivity of Three Phytotoxins Produced by the Fungus, Stagonospora cirsii

“…The effectiveness of the foliar-applied herbicides on target weeds is highly affected by the type of adjuvant added into formulation [ 20 , 21 ]. On the other hand, the addition of adjuvants can alter the selectivity of chemical herbicides and NPDHs which in turn can lead to the decrease in crop tolerance [ 22 , 23 , 24 , 25 ].…”

Absorption, translocation, and metabolism of halosulfuron and trifloxysulfuron in green kyllinga (Kyllinga brevifolia) and false-green kyllinga (K. gracillima)

“…Halosulfuron is an acetolactate synthase (ALS)-inhibiting (EC 4.1.3.18) sulfonylurea herbicide that is used to selectively control perennial sedge species, such as purple (Cyperus rotundus L.) and yellow nutsedge (Cyperus esculentus L.), and select broadleaf weeds in agronomic and horticultural crops and ornamental landscapes (Anonymous 2002b;Atland et al 2000;Haar et al 2002;McDaniel et al 2001;Whaley and Vangessel 2002). Halosulfuron also has been developed for the turfgrass market for postemergence control of yellow and purple nutsedge, Kyllinga spp., and other sedge species (Anonymous 2002a;Belcher et al 2002).…”

Joint Action of Herbicides on Weeds and Their Risk Assessment on Earthworm (Eisenia fetida L.)

“…Furthermore, some researchers reported the strong effect of mineral and vegetable oil on clodinafop-propargyl and diclofopmethyl + fenoxaprop-p-ethyl on Lolium multiflorum, Avena ludoviciana, and Phalaris minor [89]. Seed-oil-based crop oils and organosilicone adjuvants combined with halosulfuron lead to 100% control of Cyperus rotundus L. at 8 weeks after treatment (WAT) compared with a combination of halosulfuron with the nonionic or paraffinbased crop oil adjuvants (<90% control) [90]. The measurement of ED 50 and ED 90 showed that Citogate (0.1 and 0.2%) increased sulfosulfuron efficacy [91].…”