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

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.

Eficácia de [atrazine + mesotrione] para o controle de plantas daninhas na cultura do milho

“…Excelentes níveis de controle aos 14 e 28 DAA foram observados nos tratamentos com aplicação de glyphosate isolada (T16), [atrazine+mesotrione] + glyphosate (T2), atrazine + glyphosate (T3) e as associações de [atrazine+mesotrione] + tembotrione (T4, T5 e T6). Dourado Neto et al (2013) ) 84,25 a 100,00 a 100,00 a 95,00 a 100,00 a 100,00 a A adição de atrazine ao mesotrione proporcionou incremento no controle de Urochloa plantaginea, Ipomoea cordifolia, Cyperus esculentus e Commelina benghalensis em área de capim-elefante (Brighenti et al, 2017). Segundo os autores, a porcentagem de controle das plantas daninhas, 30 dias após a aplicação dos tratamentos, variou de 77% com a aplicação de 0,072 kg ha -1 de mesotrione a 85% com a aplicação da mistura em tanque de atrazine + mesotrione (1,25 + 0,072 kg ha -1 ).…”

Auxinic herbicides and tembotrione sprayed on seed-propagated elephant grass

“…The values obtained at 14 and 21 DAA were 24.5 and 35.7 while for the control without herbicides the values were 48.4 and 48.0, respectively. Tembotrione was sprayed on elephant grass isolated and mixed with atrazine, with and without mineral oil (Brighenti et al, 2017b). The results obtained by these authors indicated that tembotrione was the most phytotoxic herbicide to vegetative-propagated elephant grass.…”

“…Although elephant grass is well adapted and widespread forage throughout Brazil, weed interference in crops is still considered one of the problems during implantation, conduction, and also after harvest (Brighenti et al, 2017b;2017c). Weeds cause damage to elephant grass production and losses can reach up to 42% of forage dry matter yield depending on weed species and its density (Brighenti et al, 2017a).…”