Effects of Glyphosate on Eucalyptus After its Application on Brachiaria (Signal) Grass

Edicarlos Batista De Castro,Plínio Saulo Simões,Caio Antonio Carbonari,Gabrielle De Castro Macedo,Edivaldo Domingues Velini

doi:10.1590/2179-8087.047416

Edicarlos Batista De Castro, Plínio Saulo Simões + Show 3 more

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https://doi.org/10.1590/2179-8087.047416

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Abstract

ABSTRACT The objective of this article was to evaluate the effects of glyphosate on the initial development of eucalyptus (Eucalyptus urograndis) after its application on brachiaria (signal) grass plants (Brachiaria decumbens). The experiment was conducted in a greenhouse in a completely randomized design. Glyphosate, aminomethylphosphonic acid (AMPA) and shikimic acid concentrations were determined, along with an intoxication evaluation of the eucalyptus plant pointers and dry mass of the plants. Glyphosate was detected in eucalyptus plants after its application on B. decumbens plants, but the eucalyptus plants only presented low intoxication levels in the pointer’s leaves. No AMPA was detected in eucalyptus leaves, and only a dose of 1,440 g e.a. ha-1 of glyphosate reduced the total dry mass of eucalyptus plants. Glyphosate has the potential to cause intoxication in the crop when applied to adjacent plants.

Highlights

AND OBJECTIVESThe Brazilian forestry sector has great importance for the country’s economy, since its significant growth has been one of the factors responsible for the national trade surplus
aminomethylphosphonic acid (AMPA) was not detected in eucalyptus plants at 5, 10 and 21 days after application (DAA) of glyphosate in any of the treatments
It is observed that the collection of the lower part with an application of 720 g e.a. ha-1 of glyphosate presented higher herbicide concentration when compared to the other treatments, and the levels of the compound in the pointer collection had an increase in relation to the collection performed at 10 DAA

Summary

Introduction

AND OBJECTIVESThe Brazilian forestry sector has great importance for the country’s economy, since its significant growth has been one of the factors responsible for the national trade surplus. Weeds compete for available resources in the environment, and if not controlled at the right time they reduce forest productivity, making crop management difficult and increasing the risk of fire (Tiburcio et al, 2012). To reduce the damage caused by weed interference, management in forest areas is predominantly done by chemical control. Glyphosate (N-phosphonomethyl glycine) is a broad-spectrum systemic herbicide recommended for use in eucalyptus cultivation on the post-emergence of weeds using direct spray-jet applications (Amarante et al, 2002). This herbicide inhibits the 5-enolpyruvyl-3-phosphate synthase (EPSPS) enzyme and prevents the production of aromatic amino acids phenylalanine, tyrosine and tryptophan, which are essential for the continuity of protein synthesis in plants. Plant death is associated with failure to produce compounds that derive from the shikimic acid route, which causes deregulation in the carbon flux and reduces protein synthesis (Bradshaw et al, 1997; Velini et al, 2011)

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