Resumo - , isolados e/ou em mistura em tanque com 2,4-D, foi eficiente no controle em pós-emergência dos híbridos DKB 240 PRO2, AG 8025 RR2, AG 9045 RR2 e Pionner 30F 53HR, nos estádios V 5 e V 7 . Os mesmo resultados foram observados para o padrão clethodim, isolado e/ou em mistura em tanque com 2,4-D. Entretanto, o controle no estádio V 7 foi mais lento que no estádio V 5 . Palavras-chaves: Inibidor de ACCase, mistura em tanque, plantas daninhas Abstract -The volunteer corn Roundup Ready ® has been effective managed by ACCase graminicides as burndown prior to sowing soybean. However, before crop installation, there are other glyphosate-tolerant weeds in the field such as Conyza sp., Commelina sp., Ipomoea sp.,

-One of the factors that can influence soybeans yield is the interference imposed by weeds. This research has aimed to determine the critical period of weed interference on cv. INT 6100 RR TM soybeans. The experiment was conducted under field conditions at Campo Mourão County, Parana State, in the 2013/2014 harvest, using randomized blocks, arranged in a 2 x 8 factorial, with four replications. In the first factor, the coexistence (period before weed interference) and control (total period of weed interference prevention) periods were assessed. The second factor consisted of management times of weed species (0, 7, 14, 28, 35, 49, 56 and 130 days after emergence -DAE). The evaluations performed were density and shoot dry matter of the weed community, height, number of pods, thousand grain weight and soybean yield. Among the weed species in soybean crops, there was predominance of eudicotyledonous ones (82%). The yield results allowed establishing, for cv. INT 6100 RR TM soybeans at Campo Mourão County, Parana State, a critical period for preventing interference between 24-38 DAE.Keywords: coexistence, weed control, competition, Glycine max. daninhas: 0, 7, 14, 28, 35, 49, 56 e 130 (ciclo todo) RESUMO -Um dos fatores que podem influenciar a produtividade da cultura da soja é a interferência imposta pelas plantas daninhas. A pesquisa teve como objetivo determinar o período crítico de prevenção à interferência das plantas daninhas

RESUMO - Plantas daninhas são fatores limitantes à produtividade de soja e milho pela matointerferência, principalmente o capim amargoso (Digitaria insularis), cuja ocorrência aumenta anualmente devido à resistência ao herbicida glyphosate. Além da competição direta com a planta cultivada, a planta daninha pode atuar como hospedeiro alternativo de nematoides. Assim, foi avaliada a suscetibilidade do capim amargoso ao nematoide Pratylenchus brachyurus em relação a plantas de milho e soja. O experimento foi conduzido em casa de vegetação, comparando a reprodução do nematoide no capim amargoso, quatro genótipos de milho (DKB 285 VT PRO 2, AS 1555 PRO 2, P 30F53 YHR e DKB 330 VT PRO 2) e uma cultivar de soja (NA 5909 RR). Observou-se que a reprodução de P. brachyurus no capim amargoso foi tão eficiente quanto aquela observada nos genótipos de milho e soja. Além disto, o capim amargoso pode ser considerado uma planta suscetível ao nematoide por apresentar fator de reprodução igual a 4,2 e não diferir das demais espécies estudadas.Palavras chave: Pratylenchus brachyurus, Digitaria insularis, Zea mays, Glycine max, hospedeiro. SUSCEPTIBILITY OF MAIZE, SOYBEAN AND SOURGRASS TO ROOT LESION NEMATODE  ABSTRACT - Weeds are limiting factors to productivity of soybean and maize, due to weeds interference especially by sourgrass (Digitaria insularis), whose occurrence has increased annually due to the resistance to glyphosate herbicide. Besides the direct competition with the crop, weed can also act as an alternative nematode host. This study aimed to evaluate the susceptibility of sourgrass to the Pratylenchus brachyurus in relation to maize and soybean plants. The experiment was conducted in a greenhouse, comparing the nematode reproduction in the sourgrass and four maize genotypes DKB 285 VT PRO 2, AS 1555 PRO 2, P 30F53 YHR and DKB 330 VT PRO 2) and one of soybean (NA 5909 RR). The reproduction of P. brachyurus was as efficient in the sourgrass as in maize and soybean. In addition, sourgrass can be considered susceptible to the nematode since the reproductive factor was 4.2, similarly to the other species studied.Keywords: Pratylenchus brachyurus, Digitaria insularis, Zea mays, Glycine max, host.

Seeds of chia (Salvia hispanica L.) are known worldwide for the benefits in human nutrition. However, from the agricultural point of view, weed interference is one of the main limitations in this crop, and restricted basic information about the management with herbicides. The aim of this work was to evaluate the selectivity of herbicides applied in pre-emergence of chia crop (S. hispanica). It was carried out an experiment in the field at the Universidade Estadual do Centro-Oeste, Guarapuava-PR, using randomized complete block design, with ten treatments and four replications. The treatments applied in the pre-emergence of chia were constituted by the herbicides: sulfentrazone (100, 200, 400 and 800 g ha-1), oxyfluorfen (720 g ha-1), s-metolachlor (1920 g ha-1), flumioxazin (50 g ha-1), diclosulan (25 g ha-1), trifluralin (1800 g ha-1) and a control without application. Oxyfluorfen, s-metolachlor, flumioxazin and diclosulan were not selective for application in chia crop in pre-emergence, unlike trifluralin, which showed high selectivity. Sulfentrazone presented viability only at the dose of 100 g ha-1 .

RESUMO - A associação de herbicidas e inseticidas é uma prática comum entre os agricultores, entretanto, muitas vezes pode provocar injúrias à cultura do milho. O trabalho teve como objetivo avaliar a seletividade de herbicidas em mistura em tanque com inseticidas de diferentes grupos químicos, no crescimento inicial de hibridos de milho. Dois experimentos foram conduzidos separadamente em estufa plástica com dois híbridos de milho (30F35 e 2B-710), utilizando como unidades experimentais vasos com duas plantas nos estádios fenológicos V3 e V6. O delineamento experimental foi o inteiramente casualizado, com cinco repetições. Foram avaliados 31 tratamentos, representados pela aplicação de seis herbicidas (atrazine, nicosulfuron, foramsulfuron + iodosulfuron, mesotrione, carfentrazone e 2,4-D, nas doses de 2000; 37,5; 36+2,4; 144; 10 e 1000 g ha-1, respectivamente) isolados e em mistura com quatro inseticidas (permethrin, methomyl, chlorpyrifos ethyl e novarulon, nas doses de 26,9; 64,5; 240 e 15 g ha-1, respectivamente) e uma testemunha sem aplicação. Avaliou-se a intoxicação das plantas aos 7 e 14 dias após a aplicação (DAA), o teor de clorofila das folhas, número médio de folhas por planta, massa seca da parte aérea e das raízes aos 14 DAA. Os resultados foram variáveis em função do híbrido e estádio fenológico na aplicação, sendo as misturas menos prejudiciais ao milho quando aplicadas em V3. Os tratamentos com atrazine foram os que menos afetaram o crescimento inicial dos híbridos. As misturas nicosulfuron + chlorpyrifos ethyl, mesotrione + chlorpyrifos ethyl e 2,4-D + chlorpyrifos ethyl foram as que mais prejudicaram o híbrido 30F35. Por outro lado, a mistura carfentrazone + chlorpyrifos ethyl foi a que mais afetou o crescimento inicial do híbrido 2B-710.Palavras-chave: fitointoxicação, antagonismo, estádio de desenvolvimento, Zea mays. SELECTIVITY OF HERBICIDES AND INSECTICIDES TANK MIXTURES APPLIED IN MAIZE HYBRIDS  ABSTRACT - The association of herbicides and insecticides despite often cause damage to the corn crop is a common practice among farmers. This study aimed to evaluate the initial selectivity of herbicides in tank mixture with insecticides from different chemical groups in maize. Two experiments were carried out in plastic greenhouse, using as experimental units pots with two maize hybrids (30F35 and 2B-710) in V3 and V6 phenological stages. A completely randomized experimental design was used, with five replications. Thirty-one treatments were represented by applying six herbicides (atrazine, nicosulfuron, foramsulfuron+iodosulfuron, mesotrione, carfentrazone and 2.4- D) isolated and in combination with the four insecticides (permethrin, methomyl, chlorpyrifos ethyl and novarulon) and a check without application. The phytointoxication was evaluated at 7 and 14 days after application (DAA), the chlorophyll content in leaves, total number of leaves, dry mass of the aerial part and roots at 14 DAA. The results were dependent of hybrid and corn stage in the application, and mixtures were less harmful when applied in V3 stage. The treatments with atrazine affected less the initial growth of the two hybrids. The mixtures of nicosulfuron+chlorpyrifos ethyl, mesotrione+chlorpyrifos ethyl and 2.4-D + chlorpyrifos ethyl were the most prejudicial to the hybrid 30F35. In addition, the carfentrazone + chlorpyrifos ethyl mixture was the most harmful to the initial growth of the hybrid 2B-710.Keywords: phytointoxication, antagonism, development stage, Zea mays.