Control of volunteer corn with rates of post-emergent ACCase inhibitors applied at different phenological stages

• Published in: Colloquium agrariae Vol. 16; no. 5; pp. 35 - 46
• Main Authors: Santos, Bárbara Suellen de Almeida, Lopes, Abílio Felipe Oliveira, Oliveira, Guilherme Mendes Pio de, Dalazen, Giliardi
• Format: Journal Article
• Language: English
• Published: 08.10.2020
• ISSN: 1809-8215; 1809-8215
• DOI: 10.5747/ca.2020.v16.n5.a393

The occurrence of volunteer corn (Zea maysL.) has been common in Brazilian crops due to the adoption of a succession of soybean (Glycine max(L.) Merrill) and corn resistant to glyphosate. The aim of this work was to evaluate the control of volunteer corn using different rates of acetyl-CoAcarboxylase (ACCase) inhibitors herbicides at different phenological stages. The experiment was carried out in a greenhouse in a completely randomized design. The experiment was organized in a factorial scheme (3x7x2) with three herbicides (clethodim, quizalofop-P-tefuryl and clethodim + quizalofop-P-ethyl) applied atseven rates [0; 25; 50; 100; 200; 400 and 800 mL of commercial product (C.P.) ha-1], andat two corn phenological stages (V3 and V6). Visual control (%) assessments were carried out at 14, 21 and 28 days after application of treatments (DAT) and shoot dry mass (SDM) at 28 DAT. The data were submitted to analysis of variance and to complementary analysis by logistic regression adjustment. For allherbicides, the control of volunteer corn was greater at V3 stage, requiring lower rates compared to V6. Complete visual control of volunteer corn plants at V3 was obtained with rates of 25 mL C.P. ha-1for all herbicides evaluated, corresponding to 6, 3 and 6 + 3 g a.i. ha-1of clethodim, quizalofop-P-tefuryl and clethodim + quizalofop-P-ethyl, respectively. For V6 application, 400 mL C.P. ha-1of clethodim (equivalent to 96 g a.i. ha-1) and 100 mL C.P. ha-1of quizalofop-P-tefuryl (equivalent to 12 g a.i. ha-1) and clethodim + quizalofop-P-ethyl (equivalent to 24 + 12 g a.i. ha-1) were necessary to achieve 100% of plant mortality. Thus, the efficiency of clethodim was more dependent on the stage of application compared to others herbicides, requiring higher rates to achieve complete control of volunteer corn at V6.