D. Martins

Translocação dos herbicidas glyphosate e imazamox em plantas de aguapé

Eichhornia crassipes is one of the main weeds found in aquatic environments, being undesirable for many activities. The aim of this study was to evaluate the translocation of glyphosate and imazamox in E. crassipes. Eight intervals were studied for cutting leaves that received herbicides: 2, 4, 6, 8, 12 and 24 hours after application (HAA), and a treatment with no cutting (untreated). The glyphosate dose was 2,160 g a.e. ha-1 (commercial product - Rodeo) + 0.5% v v-1 Aterbane adhesive spreader and imazamox at 290.4 g i.a. ha-1 (commercial product - Clearcast). The treatments were installed in a completely randomized design with four replications. Glyphosate showed a bad control for all the periods of leaf cutting. The imazamox did not provide control within 12 HAA, while from 24 HAA onward the control was effective. There was not a great mobility of the glyphosate molecule in water hyacinth plants, a period above 24 hours being needed for a satisfactory translocation. For imazamox at least 24 hours were needed after herbicide application for the translocation to occur along with subsequent control.

Eficiência de herbicidas no controle de plantas daninhas latifoliadas em mamona

-1 ), carfentrazone-ethyl (30 g ha -1 ), flumioxazin (25 g ha -1 ), glyphosate (720 g ha -1 ) e glyphosate + saflufenacil (720 + 28 g ha -1 ) aplicados em pos-emergencia em tres especies de plantas daninhas (Richardia brasilienses, Sida rhombifolia e Ipomoea grandifolia), alem de uma testemunha sem aplicacao de herbicida. Os herbicidas foram pulverizados quando as plantas de mamona apresentavam 0,50 a 0,70 m de altura. As avaliacoes visuais de controle foram realizadas aos 3, 7, 14, 21 e 28 dias apos a aplicacao dos tratamentos. O estudo foi instalado no delineamento experimental em blocos casualizados, com tres repeticoes. O herbicida saflufenacil foi eficiente no controle de todas as plantas daninhas estudadas, sendo que os herbicidas carfentrazone-ethyl e flumioxazin obtiveram apenas controles satisfatorios das plantas daninhas. A mistura testada foi eficiente no controle de todas as plantas daninhas. PALAVRAS-CHAVE: Carfentrazone-ethyl, Ricinus communis, flumioxazin, saflufenacil.

Eficácia do glyphosate e 2,4-D no controle de Commelina villosa

The aim of this study was to evaluate the efficacy of glyphosate and 2,4-D alone and in combination, in the control of Commelina villosa. We studied two methodologies for evaluating herbicide absorption in eight time intervals for washing (simulating rainfall after application) and cutting of leaves (simulating abortion as a defense strategy): 2, 4, 6, 8, 12, 24 and 48 hours after herbicide application, and a treatment without washing or cutting the leaves in a completely randomized design with four replications in a 3 x 7 + 1 factorial design (three herbicides x seven periods - hours after application). Herbicides and doses tested were: glyphosate (1,440 g ha-1), 2,4-D (720 g ha-1) and a mixture of glyphosate + 2,4-D (1,080 + 720 g ha-1). The simulation of rain interfered negatively in the plant control with glyphosate. The control with the herbicide 2,4-D was affected only for the period of 2 hours. Periods of rain simulation did not influence the control of plants with a mixture of glyphosate + 2,4-D. For the study with the cutting of treated leaves, all treatments regardless of the period of cutting the leaves were influenced negatively in terms of plant control, the plants showing regrowth when treated with 2,4-D alone.

Seletividade do herbicida saflufenacil aplicado em pós-emergência em dez variedades de cana-de-açúcar na condição de soca

This study was aimed to evaluate the selectivity of the herbicide saflufenacil applied alone and mixed, in post-emergence on 10 sugarcane cultivars in the second year after planting. The experiment was carried out in Botucatu, state of Sao Paulo, Brazil. The experimental design was a randomized split plot with 4 replications, with the cultivars set up in the plot and the herbicides in the subplot. The treatments were: saflufenacil + Assist (0.07 kg ha-1 + 0.5 v/v); saflufenacil + Break Thru (0.140 kg ha-1 + 0.05% v/v); saflufenacil (0.280 kg ha-1) and ametryne + clomazone (2.0 + 3.0 L ha-1) applied at 49 days after first harvest, and a control without application. The plants had from 2 to 4 leaves at the application time. The cultivars were: SP83-2847, SP80-3280, RB855453, SP80-1842, SP89-1115, RB867515, PO-8862, RB855156, SP80-1816 and SP81-3250. The herbicide was applied using Teejet XR11002VS spray equipment with six spray nozzles, at 200 kPa and, 200 L ha-1 spray volume. Visual evaluations were made at 3, 7, 15, 21, 30, 45 and 60 days after application. The initial visual injuries observed in the sugarcane plants were dependent on cultivars, the herbicides and, doses tested. All chemical treatments tested were selective to the different cultivars studied, without affecting the crop and sugar production.