Control of Digitaria insularis (L.) Fedde in eucalyptus forests: shading increases sensitivity to glyphosate applied alone and in a mixture with carfentrazone-ethyl

• Published in: Discover Agriculture Vol. 2; no. 1; pp. 1 - 11
• Main Authors: Ferreira, Guilherme Augusto Paiva, Donato, Luan Mateus Silva, Montes, William Gomes, Rocha, Leonardo Michel, Tuffi Santos, Leonardo David
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 05.02.2024; Springer
• Subjects: Agricultural Economics; Agriculture; Biomedical and Life Sciences; Biotechnology; Dose reduction; Herbicide mixture; Life Sciences; Physiology; Planted forests; Sourgrass; Sourgrass; Physiology; Herbicide mixture; Planted forests; Dose reduction
• ISSN: 2731-9598; 2731-9598
• DOI: 10.1007/s44279-024-00014-5

Shading, the predominant condition in most of the eucalyptus cultivation cycle, causes changes in the morphological and physiological weed's characteristics, which can alter their responses to glyphosate and carfentrazone-ethyl, important herbicides for the crop. The objective was to evaluate the influence of light on the efficiency of glyphosate and carfentrazone-ethyl used alone and in a mixture in Digitaria insularis control, a priority pest in the crop. The experiment was carried out in a 3 × 6 factorial scheme. The first factor corresponded to 3 cultivation environments (full sunlight, 45 and 63% shading) and the second factor to doses of glyphosate and carfentrazone-ethyl applied isolated (1920 and 40 g ai ha −1 ) and mixed (1536 + 8; 1152 + 16; 768 + 24 and 384 + 32 g ai ha −1 ), respectively. Shading increased D . insularis sensitivity to glyphosate alone and in a mixture with carfentrazone-ethyl. In shading, the glyphosate application alone at a dose of 1920 g ha −1 and in a mixture with carfentrazone-ethyl at doses of 1536 + 8 and 1152 + 16 g ha −1 were efficient in D. insularis control. In the environment of 63% shading, the dose of 768 + 24 g ha −1 was also efficient in this species control. None of the doses were effective in controlling D. insularis in full sunlight. Isolated carfentrazone-ethyl was inefficient in controlling D. insularis , regardless of the growth environment. Shading increases the quantum yield of photosystem II and reduces the electron transport rate, photosynthetic rate, stomatal conductance, and transpiration rate of D. insularis . In shady environments, it is possible to control D. insularis with lower glyphosate doses, used alone and mixed with carfentrazone-ethyl.