Adjuvant Effects on Absorption, Translocation, and Metabolism of Haloxyfop-Methyl in Corn (Zea mays)

Abstract

The effects of adjuvants and relative humidity (RH) on absorption, translocation, and metabolism of the methyl ester of14C-haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid} in corn (Zea maysL. ‘B73 X Mo17’ hybrid) were evaluated. Addition of 1.0% (v/v) petroleum oil concentrate (POC) to the treatment solution resulted in greater foliar absorption and translocation of14C than addition of 1.0% (v/v) soybean oil concentrate (SBOC), 0.1% (v/v) oxysorbic (20 POE) (polyoxyethylene sorbitan monolaurate) (OXY), or no adjuvant (NONE). The least amount of14C absorption occurred in the treatment containing OXY. Absorption and translocation of radioactivity were significantly greater at 70% RH than at 30% RH. Thin-layer chromatography revealed that most of the14C recovered from treated plants was in haloxyfop-methyl 5 h after treatment (HAT). The remaining14C recovered was haloxyfop and an unidentified polar metabolite. The average percentage of14C-haloxyfop in the nonabsorbed fraction was 5, 39, 7, and 7% for treatments containing NONE, OXY, POC, and SBOC, respectively. The ratio of haloxyfop-methyl to haloxyfop and the percentage of polar metabolite in the absorbed14C fraction was not different among adjuvant treatments or between levels of RH.

Comparing Techniques for Quantifying Haloxyfop Absorption and Translocation in Johnsongrass (Sorghum halepense)

“…Hendley et al (8) applied 90 pi to two or three leaves on the same quackgrass plant. In their studies 84% of the radiolabel was removed in the leaf wash 72 h after treat ment, which is considerably greater than the 5% average reported in other absorption studies with ,4 C-haloxyfop (3,7,10,16). Chandrasena may be due, in part, to greater absorption in more mature leaves.…”

“…Regardless of droplet size, the solution quickly spread out on the leaf surface apparently preclud ing any potential effect of droplet size. Other ,4 C-haloxyfop absorption translocation studies also used a surfactant in the treatment solution (3,7,16). Maroder et al (10), however, both applied and washed off the radiolabel in methanol without surfactant which may account for the exceptionally high levels of radiolabel removed by the leaf wash (20% of recovered 14 C).…”

“…At harvest, the treated leaf of each plant was removed, and the treated area of the leaf was washed three times for 30 s each time in 15 ml mixture of commercially formulated haloxyfop and POC prepared as described above. A 1-ml aliquot of each wash solution was added to 11 ml of liquid scintilla tion cocktail 6 for quantification of radioactivity using liq uid scintillation spectrometry 7 . Plants were then sectioned into the following parts: (1) tip of treated leaf distal to the treated area, (2) treated area of the treated leaf, (3) base of treated leaf below the treated area (from treated area in cluding the leaf sheath to point of attachment at the node), (4) plant tissue above the node of the treated leaf, and (5) plant tissue below the node of the treated leaf.…”

Influência de chuva simulada na eficácia de diferentes formulações e doses de glyphosate

“…Como a absorção de qualquer substância pela planta precede a sua translocação, a taxa de absorção determina a quantidade disponível para transporte e para o efeito final na planta. Os dados obtidos sugerem que diferenças nas taxas de absorção dos produtos (formulações) podem ter sido responsáveis pelas suas velocidades de ação, fato também verificado por Harrison & Wax (1986) quando estudaram o efeito de diferentes adjuvantes na absorção de haloxyfop-methyl. A velocidade de ação de herbicidas dessecantes pode ser importante para o estabelecimento de culturas no sistema plantio direto, evitando a competição já nos estádios iniciais da cultura.…”

Physiological basis for CGA-248757 and flumiclorac selectivity in five plant species

“…Environmental conditions at application (Doran and Anderson 1976), herbicide rate (King and Oliver 1992), weed size (Kells et al 1984), interactions with other herbicides (Hatzios and Penner 1985), and the addition of an adjuvant (Roggenbuck et al 1990) influence herbicidal activity. Enhanced herbicidal efficacy generally reflects increased herbicide absorption (Harrison and Wax 1986); however, increased herbicide absorption does not always correlate with increased efficacy (Starke et al 1996). Ritter and Coble (1981) reported that G. max tolerance to the diphenyl ether herbicide acifluorfen was explained by less rapid herbicide absorption and translocation and increased metabolism.…”