Influence of Emulsifiable Oils and Emulsifier on the Performance of Phenmedipham, Metoxuron, Sethoxydim, and Quizalofop

Abstract

Field and growth chamber experiments were conducted to investigate the influence of emulsifiable mineral oil, emulsifiable rapeseed oil, and the emulsifier (polyoxyethylene C13/C15oxo alcohol) on the efficacy of phenmedipham and metoxuron against common lambsquarters, and of sethoxydim and the ethyl ester of quizalofop against winter wheat. In field studies, mineral oil and rapeseed oil were equally effective in increasing the efficacy of phenmedipham (0.24 and 0.48 kg ai/ha), metoxuron (0.6 and 1.2 kg ai/ha), and sethoxydim (0.05 and 0.1 kg ai/ha), but mineral oil was superior to rapeseed oil with quizalofop. In growth chamber studies, mineral oil and rapeseed oil were equally effective in increasing the efficacy of metoxuron, sethoxydim, and quizalofop-ethyl, but rapeseed oil was more effective than mineral oil with phenmedipham. Both in the field and in the growth chamber, the emulsifier was at least as effective as the oil adjuvants, when combined with all herbicides except sethoxydim. The herbicide doses giving 50% response (ED50) were determined for the growth chamber experiments. The adjuvants reduced the ED502.7-fold with phenmedipham, 51-fold with metoxuron, 2.7-fold with sethoxydim, and 6.8-fold with quizalofop when averaged over the three adjuvants. It was concluded that rapeseed oil (all tested herbicides except quizalofop) or the emulsifier (all tested herbicides except sethoxydim) can serve as a substitute for mineral oil.

Effects of temperature and concentration of the accelerators ethoxylated alcohols, diethyl suberate and tributyl phosphate on the mobility of [14C]2,4-dichlorophenoxy butyric acid in plant cuticles

“…The biological activity of a systemic crop‐protection agent can be unsatisfactory when the penetration of the active ingredient (AI) into the leaves is too slow 1–8. Rates of cuticular penetration are often limited by the low permeability of the cuticle, especially with an AI of high molecular mass and at low temperatures 9.…”

Efficacy evaluation of tribenuron methyl herbicide by using different adjuvants for common lambsquarters (Chenopodium album L.) control

“…Also an increase in the penetration dose of active ingredient via disordering of the cuticular waxes is a more important factor in improving the efficiency of herbicides (Rashed-Mohassel et al, 2011). Other researchers have demonstrated that the vegetable oils improved weed control by 2,4-D, phenmedipham (Muller et al, 2002), glyphosate (Gauvrit et al, 2007), metoxuron, sethoxydim, and quizalofop (Ruiter et al, 1997). Vegetable oils such as castor and canola oil probably disrupt and solubilize cuticular waxes (Zabkiewicz, 2000) and consequently, facilitate the penetration of the active ingredient (McMullan and Chow, 1993).…”

Oil emulsions increase efficacy ofPhoma herbarumto control dandelion but are phytotoxic

“…Three vegetable oil emulsions (B1, B2, B3) were compared with the standard treatment (PDB). These emulsions were based on the paraffinic-vegetable oil emulsions in Group A, but paraffinic oils were replaced with vegetable oils since these are considered to be more environmentally desirable (Akesson et al 1989;Auld 1993;de Ruiter et al 1997), can differ in their properties as adjuvants (Gauvrit & Cabanne 1993) and selected vegetable oils had shown some promise in initial trials (Stewart-Wade, unpublished data); and emulsifiers were varied to reduce possible phytotoxicity (de Ruiter et al 1997) and viscosity (Yang et al 1993). Emulsion B1 contained 10% soybean lecithin, 45% canola oil and 45% soybean oil in the oil phase; 0.25% sodium alginate and 0.5% dolomitic lime in 20% PDB in the aqueous phase; with an oil:aqueous ratio of 1:1.…”