Interaction between ACCase inhibitors and broadleaf herbicides to the control of Italian ryegrass

Management of Italian ryegrass is frequently done with tank-mix or sequential applications of herbicides. The aim of this study was to evaluate the interaction of haloxyfop-p-methyl or clethodim with ۲,۴-D, chlorimuron-ethyl and cloransulam-methyl applied in a tank mix or sequential in the control of Italian ryegrass. The three experiments were performed in a factorial arrangement and a randomized complete block was designed, with four replications. Factor A consisted of the haloxyfop (۶۲.۳۵ g a.i. ha-۱), clethodim (۱۰۸ g a.i. ha-۱) and chlorimuron (۲۰ g a.i. ha-۱) (Experiment I); haloxyfop, clethodim and cloransulam (۳۹.۹۵g a.i. ha-۱) (Experiment II); haloxyfop, clethodim and ۲,۴-D (۱۰۰۵ g a.e. ha-۱) (Experiment III). Factor B consisted of tank-mix or sequential (same day) application. Treatments also included an untreated check and the isolated application of herbicides. Haloxyfop and clethodim alone, clethodim+۲,۴-D, haloxyfop+cloransulam, haloxyfop+chlorimuron, clethodim+cloransulam, clethodim+chlorimuron controlled Italian ryegrass. However, an antagonistic response of haloxyfop+۲,۴-D was observed. Based on this study, haloxyfop should not be applied associated with ۲,۴-D in the control of Italian ryegrass; however, the mixtures of ACCase+chlorimuron, ACCase+cloransulam, and clethodim+۲,۴-D were efficient in the control of the Italian ryegrass.

Keywords:

Lolium perenne ssp. multiflorum , Antagonism , sinergism