HPPD-Inhibiting Herbicides Alone or in Tank-Mix with Atrazine in Elephant Grass

Alexandre M Brighenti,Yago V Guerra Varotto,Francisco J S Ledo,Leonardo H F Calsavara,Juarez C Machado

doi:10.5539/jas.v9n11p234

Abstract

The interference imposed by weeds is one of the most important factors limiting elephant grass forage yield. Two experiments were carried out in 2015/2016 and 2017 to evaluate the selectivity and weed control of 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides applied alone or in combination with atrazine in elephant grass. The treatments applied in the experiment conducted in Valença, Rio de Janeiro State, Brazil, were as follows: two rates of mesotrione (0.072 and 0.144 kg ha-1 + 0.5% v/v mineral oil - Assist®), two rates of tembotrione (0.075 and 0.100 kg ha-1 + 0.5% v/v mineral oil - Aureo®), atrazine + mesotrione (1.25 + 0.072 kg ha-1 + 0.5% v/v mineral oil - Assist®), atrazine + tembotrione (1.25 + 0.100 kg ha-1 + 0.5% v/v mineral oil - Aureo®), atrazine + mesotrione (1.25 + 0.072 kg ha-1), atrazine + tembotrione (1.25 + 0.100 kg ha-1) and two checks (weed-free check and weedy check). The same herbicide treatments and a check without application were applied in an experiment conducted in Coronel Pacheco, Minas Gerais State, Brazil. Two application rates of mesotrione with the addition of mineral oil or the tank mixture of atrazine plus mesotrione, with or without the addition of mineral oil, did not provide injuries capable to reduce elephant grass forage yield. Tembotrione was phytotoxic to elephant grass when applied with mineral oil. Atrazine plus tembotrione in a tank-mix, with or without mineral oil, were also phytotoxic to elephant grass. All treatments provided satisfactory weed control.

Highlights

The majority of Brazil’s milk and meat production is based on the use of pasture
Elephant grass is known for high productive potential in tropical and subtropical regions; when properly managed, it can produce from 30 to 50 t/ha/year of dry matter (Pereira et al, 2016)
The results indicated selectivity of this herbicide to millet, since there was no damage to plant growth

Summary

Introduction

The majority of Brazil’s milk and meat production is based on the use of pasture. the search for forage species with high productivity and forage quality for cattle feeding has great importance. Elephant grass (Pennisetum purpureum Schum.) is suitable for this purpose and widely used in cattle raising, mainly for cutting, grazing and silage production (Santos et al, 2013; Maia et al, 2015). In addition to being an excellent animal feed, elephant grass can be used as raw material for the production of bio-gas, bio-oil, charcoal (Strezov et al, 2008; Rocha et al, 2017), and alcohol (Shakil et al, 2013), as well as for the generation of electricity (Ohimain et al, 2014). Elephant grass is known for high productive potential in tropical and subtropical regions; when properly managed, it can produce from 30 to 50 t/ha/year of dry matter (Pereira et al, 2016). Elephant grass is resistant to drought, diseases and pests (Schmelzer, 1997)

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