Plants in E1 treated with sulfentrazone (300 g [ha.sup.-1]) had 3.4% of injuries, reduced size, and leaf chlorosis.
Regarding the post-emergence herbicides, Lactofen (120 g ha-1) + chlorimuron (12.5 g [ha.sup.-1]), and lactofen (120 g [ha.sup.-1]) caused the greatest injuries to soybean plants at 7 [DAA.sub.POST] in all combinations with the pre-emergence herbicides (S-metolachlor, diclosulam, sulfentrazone), and with no application of pre-emergence herbicide.
The phenological stage of the target plants at application time is crucial for the efficacy of
sulfentrazone (Rodrigues and Almeida, 2011).
Additionally, based on the low levels of injury following application of both metribuzin and
sulfentrazone, it is likely that the variety chosen for these studies was tolerant to these herbicides.
Herbicide log [K.sub.PW] Sol (c) [K.sub.OW] (a) (b) Ametryn 2.63 31.5 0.2 clomazone 2.5 42.34 1.1 Diuron 2.85 88.14 0.0364 hexazinone 1.2 9.4 33 metribuzin 1.6 17.7 1.05 Simazine 2.1 21.13 0.0062
sulfentrazone 1.48 20.2 110 tebuthiuron 1.79 13.02 2.5 (a) log [K.sub.OW] partition coefficient octanol-water of herbicide (L [kg.sup.-1]) (TOMLIN, 2000).
The
sulfentrazone results were not satisfactory even in the wet season with the 100% dose for the sandy-clay-loam soil, whereas only diclosulam, sulfrentazone, tebuthiuron and trifluralin showed not satisfactory results with the 50% dose (Table 3).
Para os herbicidas testados, as doses do produto comercial foram: 0; 1,5; 3,0 e 6,0 L [ha.sup.-1]para o ametryn, 0; 1,6; 3,2 e 6,4 L [ha.sup.-1] para o diuron e 0; 0,4; 0,8 e 1,6 L [ha.sup.-1] para o
sulfentrazone.
O
sulfentrazone e um herbicida pre-emergente do grupo quimico ariltriazolinonas, que atua inibindo a enzima protoporfirinogenio oxidase, um intermediario importante na sintese da clorofila em plantas (Jacobs & Jacobs, 1987; Reddy & Locke, 1998).
Aos sete dias apos a emergencia do girassol, os maiores niveis de injuria foram observados nas plantas cultivadas nas areas que receberam a aplicacao de imazaquin, diclosulam,
sulfentrazone e imazethapyr (0,100kg [ha.sup.-1]) (Tabela 2).
No Brasil, o anidrido naftalico aplicado nas sementes de aveia branca para o controle de azevem nao diminuiu a fitointoxicacao da cultura em reposta aos herbicidas diclofop-methyl,
sulfentrazone, isoxaflutole e clomazone (RIZZARDI & SERAFINI, 2001).
A aplicacao de
sulfentrazone no estadio fenologico R3 ou no R5 reduziu a area foliar, o acumulo de materia seca total e nos orgaos, a altura da planta e o comprimento de raizes (ARRUDA et al., 1999).
