Physiological basis for antagonism induced by mixtures of quizalofop‐ethyl and bromoxynil in maize (Zea mays)

Abstract

In this study, the physiological basis for antagonism induced by mixtures of quizalofop-ethyl and bromoxynil was investigated in maize seedlings. In sequential applications, antagonism was observed when bromoxynil was applied before quizalofop-ethyl or in a mixture with quizalofop-ethyl, but was minimal when bromoxynil was applied afterwards. The degree of antagonism differed with application rates of bromoxynil and with the timing of the treatment. When test herbicides were applied locally to the second leaf, the inhibition of photosystem II (PS-II) in the herbicide-treated leaf was higher with the mixture than with bromoxynil or quizalofop-ethyl alone. Subsequent growth of the untreated third leaf inhibited by quizalofop-ethyl alone then recovered, depending on the dose of bromoxynil. There was no evidence that bromoxynil affected absorption of quizalofop-ethyl. In local applications at different positions on the second leaf, antagonism was only observed when quizalofopethyl was applied to the distal part of the leaf and bromoxynil applied to the proximal part. The antagonism of bromoxynil + quizalofop-ethyl did not occur at the level of acetyl CoA carboxylase and Hill reaction, as revealed by in vitro assays. These results suggest that bromoxynil inhibits the phloem transport of quizalofopethyl and thus antagonises its whole-plant activity in maize.

Barnyardgrass (Echinochloa crus-galli) Control as Affected by Application Timing of Glufosinate Applied Alone or Mixed with Graminicides

“…Compared with glyphosate, glufosinate applied alone will not likely provide adequate summer annual grass control; thus, producers may choose to mix herbicides to broaden and improve the spectrum of weeds controlled and reduce application cost. (Beyers et al 2002;Corkern et al 1998;Culpepper et al 2000;Green 1989;Kim et al 2005;Vidrine 1989;Vidrine et al 1995;Zhang et al 1995).…”

Development of an Enzyme-Linked Immunosorbent Assay for Quantitative Determination of Quizalofop-p-ethyl

“…Thus, a suitable analysis method, which is quick, easy, and economical for detecting its residue that might potentially contaminate water, soil, and aquatic food, is urgently needed. The current regular analysis method of quizalofop- p -ethyl is based on chromatography methods, including high performance liquid chromatography (HPLC), gas chromatography (GC), and gas chromatography−mass spectrometry (GC−MS), which are characterized by high precision and sensitivity ( 1 , − . However, these methods have a few shortcomings: the procedure is time-consuming and involves toxic solvents and reagents.…”