Application stage and doses of glyphosate in control, production of fruits and seeds of Solanum americanum
César Tiago Forte1, Ubirajara Russi Nunes2, Millena Candeia Dutra1, Emely Vitória Bona1, Maurício Albertoni Scariot1, Michele Renata Revers Meneguzzo1 and Leandro Galon3
1Centro Universitário IDEAU, Getúlio Vargas, RS, Brasil
2Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
3Universidade Federal da Fronteira Sul, Erechim, RS, Brasil
Abstract
Weeds interfere with crops of economic interest, and their control has been threatened due to how management practices are being applied, increasing cases of resistance to herbicides. The objective of the study was to evaluate the influence of the application stage and doses of glyphosate herbicide on the development characteristics of Solanum americanum and the production of fruits and seeds. The experiment was characterized as bifactorial (doses x application stages). The first factor was composed of 7 doses of glyphosate herbicide (0, 45, 90, 180, 360, 720 and 1440 g e.a ha-1) applied when there were 5 leaves and at flowering (first open flower), simulating application at the ideal time and late, respectively. The variables evaluated were control at 28 and 56 days after application of treatments (DAA), 28 DAA; plant height (cm), number of fruits per plant, seeds per fruit, total fruit production, plant dry matter and seed germination at the end of the experiment were measured. The application of glyphosate in the initial stages of the weed improved control when compared to the application at the flowering stage of the species, resulting in a lower dose of glyphosate for control. Anticipating control drastically reduced plant height, production of fruits, seeds, and dry matter mass of S. americanum, but without affecting seed germination. When applied at the 5-leaf stage, 25% (180 g e.a ha-1) of the recommended dose of glyphosate is enough for the S. americanum species not to produce descendants.
Highlighted Conclusions
1. All evaluated factors were reduced with an increase in the dose of glyphosate herbicide.
2. The best controls were observed at the weed stage of up to 5 leaves.
3. The flowering stage of the American black nightshade weed requires 4 times more glyphosate to obtain adequate levels of control.