Initial growth of cowpea-beans after application of post-emergence herbicides

Objetivou-se neste trabalho avaliar a tolerância do feijão-caupi, cultivar BSR Aracê, a diferentes herbicidas aplicados em pós-emergência, na fase inicial de crescimento das plantas. O experimento foi conduzido em casa de vegetação, em delineamento inteiramente casualizados, com quatro repetições. Os tratamentos avaliados foram: haloxyfop (60 g ha-1), lactofen (180 g ha-1), chlorimuron-ethyl (17,5 g ha-1), bentazon (576 g ha-1), bentazon + imazamox (600 + 28 g ha-1), imazethapyr (100 g ha-1), fomesafen (250 g ha-1), quizalofop-P-ethyl (62,5 g ha-1), lactofen + quizalofop-P-ethyl (180 + 62,5 g ha-1), fomesafen + quizalofop-P-ethyl (250 + 62,5 g ha-1), e uma testemunha. Foram realizadas avaliações visuais de intoxicação, altura das plantas, massa seca foliar, da haste, raiz, massa seca total e área foliar. Os herbicidas haloxyfop e quizalofop-P-ethyl causaram os menores danos ao desenvolvimento das plantas de feijão-caupi. O chlorimuron-ethyl provocou danos severos à cultura, interrompendo seu crescimento. As misturas lactofen + quizalofop-P-ethyl e fomesafen + quizalofop-P-ethyl provocaram os danos elevados à cultura, sendo que a mistura lactofen + quizalofop-P-ethyl, promoveu a morte das plantas do feijão-caupi. Concluiu-se que o feijão-caupi cv. BRS Aracê têm tolerância aos herbicidas haloxyfop e quizalofop-P-ethyl, e tolerância moderada ao formulado bentazon + imazamox e ao herbicida imazethapyr. As misturas lactofen + quizalofop-P-ethyl e fomesafen + quizalofop-P-ethyl potencializam o efeito dos herbicidas sobre a cultura do feijão-caupi. A mistura lactofen + quizalofop-P-ethyl e o herbicida chlorimuron-ethyl provocam danos irreversíveis à cultura do feijão-caupi.The objective of this work was to evaluate the tolerance of cowpea, BSR Aracê, to different herbicides applied in the post-emergence period, in the initial phase of plant growth. The experiment was conducted in a greenhouse, in a completely randomized design, with four replications. The treatments evaluated were: haloxyfop (60 g ha-1), lactofen (180 g ha-1), chlorimuron-ethyl (17,5 g ha-1), bentazon (576 g ha-1), bentazon + imazamox (600 + 28 g ha-1), imazethapyr (100 g ha-1), fomesafen (250 g ha-1), quizalofop-P-ethyl (62,5 g ha-1), lactofen + quizalofop-P-ethyl (180 + 62,5 g ha-1), fomesafen + quizalofop-P-ethyl (250 + 62,5 g ha-1) and a control. Were realized visual evaluations of intoxication, plant height, dry leaf mass, stem, root, total dry mass and leaf area. The herbicides haloxyfop and quizalofop-P-ethyl they caused minor damage to the development of cowpea plants. The chlorimuron-ethyl caused severe damage to the crop, interrupting their growth. The lactofen + quizalofop-P-ethyl and fomesafen + quizalofop-P-ethyl mixtures caused high damage to the culture, with lactofen + quizalofop-P-ethyl causing the plants to die at 21 DAAH. It was concluded that cowpea, cv. BRS Aracê, have tolerance to haloxyfop and quizalofop-P-ethyl herbicides, and moderate tolerance to imazethapyr and bentazon + imazamox. The lactofen + quizalofop-P-ethyl and fomesafen + quizalofop-P-ethyl mixtures showed a synergistic effect on bean cowpea. The lactofen + quizalofop-P-ethyl mixture and the chlorimuron-ethyl herbicide cause irreversible damage to the bean cowpea crop