Herbicides for Rooted Aquatic Macrophytes

Abstract

The aim of this study was to evaluate the effectiveness of glyphosate, 2,4-D, and diquat to control the aquatic macrophytes Brachiaria subquadripara, Hedychium coronarium, and Myriophyllum aquaticum under greenhouse conditions. The following herbicides and doses were used: glyphosate at 240, 720, 1,680, 2,640, 3,600, and 4,320 g a.e. ha-1, 2,4-D at 335, 1,005, 1,675, 2,345, and 3,015 g a.e. ha-1, diquat at 100, 200, 300, 400, 500, and 600 g a.i. ha-1, and a control with 10 replications. Sprayings were applied with a CO2-pressurized backpack sprayer at a constant pressure of 172.36 KPa, tips DG 11002, and spray solution consumption of 200 L ha-1. The effectiveness of control was evaluated visually at 3, 7, 15, 21, 30, 45, and 60 days after application (DAA) and dry matter accumulation at 60 DAA. Glyphosate promoted the best effectiveness, with 100% control of B. subquadripara, with no dry matter accumulation from 720 g a.e. ha-1. The herbicide 2,4-D presented the best control for M. aquaticum with 100% control from 1,209 g a.e. ha-1, and for H. coronarium with 99% control from 2.015 g a.e. ha-1, both doses with no dry matter accumulation. The diquat was not effective in controlling the plants of M. aquaticum and B. subquadripara, besides allowing resprouts.

Efeitos do herbicida Roundup® em Laguncularia racemosa (L.) C. F. Gaertn (combretaceae)/ Effects of the herbicide Roundup® em Laguncularia racemosa (L.) C. F. Gaertn (combretaceae)

“…No Brasil, estudos realizados sobre a toxicidade do Roundup em espécies de mangue são escassos e a maioria dos trabalhos relacionados ao tema foca nos efeitos causados na fauna ou nos sedimentos. Entretanto, existem alguns estudos com macrófitas aquáticas/hidrófilas, com destaque para os trabalhos realizados com Spirodela punctata (Santos et al 2001), Eichhornia crassipes (Cardoso et al 2003), Pistia stratiotes, Salvinia auriculata e Eichhornia crassipes (Foloni e Pitelli 2005), Azolla caroliniana (Silva et al 2012), Ruppia maritima (Castro et al 2015), Brachiaria subquadripara, Hedychium coronarium e Myriophyllum aquaticum (Cerveira et al 2019). O objetivo desse trabalho foi determinar os efeitos do formulado comercial Roundup sobre a espécie de mangue branco L. racemosa, a qual desempenha importantíssimo papel ecológico em ambientes estuarinos.…”