Dose-response Curves of Herbicides Applied in Pre-Emergency of Euphorbia hyssopifolia L

The species Euphorbia hyssopifolia L. belongs to the Euphorbiaceae family, and occurs in pasture areas, roads and sugarcane fields. Therefore, it can interfere with agricultural production and thus needs to be managed. The key to solving this problem is the construction of dose-response curves with herbicides commonly registered for crops. Thus, the present work aims to use dose-response curves with herbicides widely used in sugarcane cultivation belonging to the mechanisms of action of ALS inhibitors (acetolactate synthase enzyme), carotenoid biosynthesis inhibitors, photosystem II (PS II), cellulose biosynthesis inhibitors, protox inhibitors (protoporphyrinogen oxidase enzyme) and VLCFA inhibitors (very long chain fatty acids), for the control of E. hyssopifolia. The experiments were conducted in a greenhouse at the Engineering and Agricultural Sciences Campus of the Federal University of Alagoas, with pre-emergence application of weeds, the herbicides diclosulam, imazapic, metsulfuron-methyl, clomazone, isoxaflutole, indaziflam, hexazinone, tebuthiuron, amicarbazone, flumioxazin, oxyfluorfen, sulfentrazone, s-metolachlor and pyroxasulfone in increasing doses of: 0; 12.5; 25; 50; 100; 200 and 400% at the recommended dose for sugar cane. As a result of the study, E. hyssopifolia showed greater sensitivity to the herbicides diclosulam, imazapic, metsulfuron-methyl, clomazone, hexazinone, indaziflam, flumioxazin, oxyfluorfen and pyroxasulfone, as the lethality of their doses occurred below 20% of the commercial dose indicated for sugar cane crops. As for the herbicides isoxaflutole, tebuthiuron, amicarbazone, sulfentrazone and s-metolachlor, the species exhibited lower sensitivity, with a lethal dose recorded above 50% of the respective recommended commercial dose.