Mitigation of glyphosate side effects on non-target plants: use of different agrochemicals as protectants in common bean plants

Abstract

Objetivou-se avaliar o efeito de diferentes agroquímicos na reversão da fitotoxidez do glyphosate (Roundup WG 0,06 kg ha -1 ) em feijoeiro (Phaseolus vulgaris cv. Carioca), a aplicação do herbicida foi realizada em todas as plantas exceto na testemunha absoluta, aos 31 dias após o plantio (DAP), no estádio de 3° trifólio. Aos 36 DAP, as plantas foram tratadas com: ácido fúlvico 25% (1000 ml ha -1 e 2000 ml ha -1 ), aminoácido (500 ml ha -1 e 1000 ml ha -1 ), fosfito (2000 ml ha -1 e 4000 ml ha -1 ), além de bioestimulante (250 ml ha -1 e 500 ml ha -1 ). Aos 36, 40, 46 e 54 DAP foram conferidas notas às plantas e aos 54 DAP as plantas foram coletadas e determinou-se a área foliar e a massa seca de três plantas. Pelas notas conferidas verificou-se que somente a testemunha absoluta e o aminoácido 500 ml ha -1 apresentaram menores danos do que o tratamento com glyphosate. A área foliar somente mostrou-se maior na testemunha absoluta, sendo que a massa seca revelou-se superior na testemunha absoluta e nos tratamentos com aminoácido 500 e 1000 ml ha -1 . Abstract Glyphosate is an herbicide widely used in agriculture. However, it may causes phytotoxic effects on non-target plants (crops), generating productivity losses. Currently there are evidences about agrochemicals as potential mitigators of glyphosate side effects. Therefore, the objective of this study was to evaluate the effects of distinct doses of fulvic acid 25% (k tionic® 1000 and 2000 mL ha-1), amino acids (Codamin BR® 500 and 1000 mL ha-1), phosphite (Nutex0-30-20®, 2000 and 4000 mL ha-1) and biostimulant (Byozime TF® 250 and 500 mL ha -1) in reversion of fitotoxicity caused by glyphosate on ‘Carioca’ common bean plants. For comparison, plants treated only with glyphosate, and untreated plants (control) were also evaluated. Glyphosate spray (Roundup WG 0.06 kg ha -1) was performed at 31 days after planting (DAP), and agrochemicals were applied at 36 DAP. Phytotoxicity symptoms, as well as leaf area, dry mass of leaves and stems, and physiological indexes were evaluated at 54 DAP. Application of amino acid-based product (500 mL ha-1) significantly reduced (29.90%) phytotoxicity symptoms. Both doses of amino acid-based product increased dry mass of leaves; therefore, they were able to maintain the leaf weight ratio similar to the control plants. However, there was a decrease in leaf area, which was not reverted by any of the agrochemicals. It is concluded that application of amino acid-based product Codamin BR 500 mL ha-1) reduces, even partially, glyphosate phytotoxicity in ‘Carioca’ common bean plants.