COWPEA TOLERANCE TO OXADIAZON TOLERÂNCIA DO FEIJÃO-CAUPI AO HERBICIDA OXADIAZON

• Main Authors: Ronaldo Ribeiro de Morais, José Roberto Antoniol Fontes, José Ricardo Pupo Gonçalves
• Format: Article
• Language: English
• Published: Universidade Federal de Goiás 2009-12-01
• Series: Pesquisa Agropecuária Tropical
• Subjects: Vigna unguiculata; controle químico de planta daninha; levantamento florístico
• Online Access: http://www.revistas.ufg.br/index.php/pat/article/view/6241

&lt;!-- @page { margin: 2cm } P { margin-bottom: 0.21cm } --&gt; &lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="pt-BR" align="JUSTIFY"&gt;&lt;span style="color: #000000;"&gt;&lt;span style="font-family: Times New Roman,serif;"&gt;&lt;span style="font-size: small;"&gt;The use of herbicides for weed control in cowpea [&lt;em&gt;Vigna unguiculata&lt;/em&gt; (L.) Walp.] can result in highly effective control and lower production costs, if compared to mechanical control, especially weeding. However, not many studies were conducted in order to evaluate crop tolerance to herbicides. The objectives of this study were to evaluate cowpea tolerance, BRS Guariba cultivar, to the oxadiazon herbicide, applied in pre-emergence, at 200 g, 400 g, 600 g, 800 g, and 1,000 g of active ingredient (a.i.) ha&lt;sup&gt;-1&lt;/sup&gt;, and weed control effectiveness. The weeds identified were &lt;em&gt;Cleome affinis&lt;/em&gt;, &lt;em&gt;Commenlina benghalensis&lt;/em&gt;, &lt;em&gt;Cyperus rotundus&lt;/em&gt;, and &lt;em&gt;Euphorbia heterophylla&lt;/em&gt;. The cultivar BRS Guariba was very tolerant to all doses tested, and the weed control level was good. Grain yields obtained with doses above 600 g &lt;sub&gt;a.i. &lt;/sub&gt;ha&lt;sup&gt;-1&lt;/sup&gt; were excellent, comparable to weeding performance during the critical period of weed competition, between 20 and 40 days after seedling emergence (1,561 kg ha&lt;sup&gt;-1&lt;/sup&gt;). The negative interference of weeds, throughout the cowpea life cycle, decreased yield by 59%.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt; &lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="en-US" align="JUSTIFY"&gt;&lt;!-- @page { margin: 2cm } P { margin-bottom: 0.21cm } --&gt; &lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="en-US" align="JUSTIFY"&gt;&lt;span style="color: #000000;"&gt;&lt;span style="font-family: Times New Roman,serif;"&gt;&lt;span style="font-size: small;"&gt;KEY-WORDS: &lt;em&gt;Vigna unguiculata&lt;/em&gt;; chemical weed control; floristic inventory.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;/p&gt;<br>&lt;!-- @page { margin: 2cm } P { margin-bottom: 0.21cm } --&gt; &lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="pt-BR" align="JUSTIFY"&gt;&lt;span style="color: #000000;"&gt;&lt;span style="font-family: Times New Roman,serif;"&gt;&lt;span style="font-size: small;"&gt;O uso de herbicidas, para controle de plantas daninhas na cultura do feijão-caupi [&lt;em&gt;Vigna unguiculata&lt;/em&gt; (L.) Walp.], pode resultar em elevada eficácia de controle e menores custos de produção, quando comparados ao controle mecânico, principalmente capinas. Entretanto, são escassos os trabalhos de avaliação da tolerância desta cultura a herbicidas. Os objetivos deste trabalho foram avaliar a tolerância do feijão-caupi, variedade BRS Guariba, ao herbicida oxadiazon, aplicado em pré-emergência, com doses de 200 g, 400 g, 600 g, 800 g e 1.000 g de ingrediente ativo (i.a.) ha&lt;sup&gt;-1&lt;/sup&gt;, e a eficácia de controle de plantas daninhas. As plantas daninhas identificadas na área experimental foram &lt;em&gt;Cleome affinis&lt;/em&gt;, &lt;em&gt;Commelna benghalensis&lt;/em&gt;, &lt;em&gt;Cyperus rotundus&lt;/em&gt; e &lt;em&gt;Euphorbia heterophylla&lt;/em&gt;. As plantas da variedade foram muito tolerantes a todas as doses testadas e o nível de controle de plantas daninhas foi satisfatório. As produtividades de grãos obtidas com doses acima de 600 g &lt;sub&gt;i.a. &lt;/sub&gt;ha&lt;sup&gt;-1&lt;/sup&gt; foi excelente, comparável à obtida com a realização de duas capinas, durante o período crítico de competição de plantas daninhas com a cultura, entre 20 e 40 dias após a emergência das plântulas (1.561 kg ha&lt;sup&gt;-1&lt;/sup&gt;). A interferência negativa de plantas daninhas, durante todo o ciclo de vida da cultura, reduziu a produtividade de grãos em 59%. &lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt; &lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="pt-BR" align="JUSTIFY"&gt;&lt;!-- @page { margin: 2cm } P { margin-bottom: 0.21cm } --&gt;&lt;/p&gt;&lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="pt-BR" align="JUSTIFY"&gt;&lt;span style="color: #000000;"&gt;&lt;span style="font-family: Times New Roman,serif;"&gt;&lt;span style="font-size: small;"&gt;PALAVRAS-CHAVE: &lt;em&gt;Vigna unguiculata&lt;/em&gt;; controle químico de planta daninha; levantamento florístico.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt; &lt;/p&gt;