Análise comparativa de controle do azevém a herbicidas em Dois Vizinhos-PR

Abstract

Common ryegrass (Lolium multiflorum) is considered a winter forage plant, but when established among other commercial crops, it can become a weed. This study aimed to verify the resistance and control of ryegrass collected at UTFPR-DV using herbicides. The methodology consisted of an experimentation work on the school farm in a greenhouse. The products used were glyphosate, glufosinate ammonium, clodinafop-propargyl, pyroxsulam, and an adjuvant. The design was completely randomized in a three-factor scheme (5x2x2), with factor A consisting of the herbicides glyphosate, glufosinate ammonium, clodinafop-propargyl, pyroxsulam, and a control. Factor B: with and without adjuvant. Factor C consisted of applications at two distinct times: one with 3 and 6 tillers of ryegrass. Four repetitions were performed per treatment. The first four treatments were applied with glyphosate, glufosinate ammonium, clodinafop-propargyl, pyroxsulam, and the control. Subsequently, four more treatments were performed, associating these herbicides with the adjuvant and the control. This totaled 20 treatments with 4 repetitions, where 10 treatments were applied when the ryegrass had an average of 3 tillers and the other 10 treatments when it had an average of 6 tillers. The evaluation of phytotoxicity was based on the classification table of the European Weed Research Council scale, considering that the evaluations were performed from 7 to 42 days. The treatments with glyphosate and glufosinate demonstrated to be the most effective in controlling ryegrass, from the phytotoxicity evaluation at 7 days to the final observations at 42 days. Clodinafoppropargyl began to show more evident effects from 21 days after application, indicating that its phytotoxicity occurs gradually, reaching similar results to those of glyphosate and glufosinate, which demonstrated efficacy in the first evaluations. The stage of development for controlling ryegrass plays a fundamental role, as the products showed greater efficiency in controlling Lolium multiflorum when applied in the initial stages of the crop, i.e., with an average of 3 tillers. The addition of adjuvant resulted in a significant statistical difference, especially in the treatments combined with pyroxsulam.