The development of a Brachiaria plantaginea resistant biotype to ACCase inhibitor herbicides has occurred in several soyabean production areas in Brazil, especially in Paraná State. However, little research has been conducted in order to prove scientifically the resistance using dose-response curves. In order to draw dose-response curves and determine GRso and GRso of a suspected 8. plantaginea biotype, herbicides of the chemical groups ariloxyphenoxypropionic acid (haloxyfop-rnethyl, quizalofop-p-ethyl, fluazifop-p-butil and fenoxaprop-p-ethyl) and cyclohexanodiones (sethoxydim, clethodim and butroxydim) were sprayed at rates […]

A trial was carried out in a sugar cane field in Santa Helena County, Goias State, Brazil, during the 1999/2000 growing season. The objectives were to evaluate the agronomic efficiency of a misture of trifloxysulfuron-sodium/arnetryne in the control of weeds and to evaluate the selectivity for sugar cane. The experimental design was a completely randomized block with four replications and eight treatments. The treatments were as follows: cleaned and noncleaned plots, trifloxysulfuronsodiurnJametryne (32/1280, 37/1463 and 42/1646 g/ha), trifluxysulfuron-sodium+ametryne (tank mixture), […]

The aim of this work was to evaluate the selectivity of some pre and postemergence herbicides on cassava, as well as their efficiency to control the weeds Avena sativa, Bidens pilosa, Commelina benghalensis, Raphanus sativus and Sida rhombifolia. The field trial was carried out in no-till areas, in Araruna, northwestern Paraná State. Although some herbicides provided outstanding results either in relation to weed control or crop selectivity, when both aspects were taken into consideration, the best results were achieved with […]

An experiment was carried out at Epagri, in Itajaí, Santa Catarina State (26°56’35″S and 48°45’37″W), during 1996/ 97 and 1997/98 growing seasons, to evaluate the efficacy and selectivity of 2,4-D herbicide at four rates, two times of application and two formulations, in infested rice. Herbicides were applied postemergence, with rice plants at the 3-4 leaf stage, and late postemergence, 38-39 days after planting. Herbicide formulations and rates evaluated were: 2,4-D amine at 200,400,800 and 1200 g/ha a.e. (acid equivalent) and […]

A field experiment was carried out in a sandy soil (85 % of sand) aiming at studying herbicide/nematicide interaction in sugar cane. Terbufos and carbofuran, both applied at 3000 g/ha in the furrow at planting and the herbicides oxyfluorfen–ametryne (480+ 1500 g/ha), oxyfluorfen+diuron (480+2400 g/ha) and thiazopyr+ametryn (360+ 1500 g/ha) were studied. The herbicides were applied before emergence of the sugar cane plants, with a CO2 knapsack sprayer, equipped with 6 nozzles Teejet DO 80.02. The experimental design was a […]

The effects of simulated rainfall on the performance of different formulations and doses of glyphosate in the control of Brachiaria plantaginea (Link) Hitchc. were studied under field conditions. The experimental design used was that of a split-block in strips. The strips consisted of the irrigation factor. Formulation and doses were arranged in a factorial arrangement, with four replications. Plots measured 2.5 m x 4.0 m. The irrigation factor consisted of a simulated rainfalI of 20 mm applied at different timings […]

The major problem with the sugar cane crop is weed competition, specially Panicum maximum Jacq., which is a very agressive plant. The trial was carried out at Usina São Carlos (a sugar will), in Jaboticabal-SP, during 1998/1999 aiming to study imazapyr and imazapic herbicides, sprayed alone in preemergence, or imazapic in mixture with pendimethalin, for P maximum control. The experimental design was a randomized block with nine treatments and four replications. The treatments were: controls (with and without weeds), imazapic […]

The objective of the work was evaluate the potential phytotoxic effects of s-metolachlor herbicide on different sizes of seeds of a single bean variety cultivar belonging to a same lot, in low temperature conditions. The experiment was carried out in a growth chamber with 12 hours photofase, 16/13 ± 3°C (day/night) temperature (until plant emergence) and 300 umol of photosynthetically active radiation (PAR)/m2 s. The cultivar used was Pérola, belonging to the Carioca group. The treatments included the combination of […]

The objective of this research was to evaluate the agronomic efficiency of herbicides applied as a postemergence treatment on the control of weeds and to evaluate the tolerance of the treatments for com. The experiment was developed during the period from december/OO to april/O 1, at FEP-UNESP at Selvíria, Mato Grosso do Sul, Brasil. The experiment was carried out in a conventional system and the hybrid com used was ‘Master ‘ at a spacing of 0.9 m between rows with […]

No-tillage systems, characterized by presence of straw on soil surface, provoke some alteration in weed population dynamics, such as a reduction in annual species and increase in perennial species, as well as the appearence of weeds that are hard to control , such as Richardia brasiliensis. The objective of the present work was to evaluate the efficiency of burndown herbicides in Richardia brasiliensis control and their effect on yield and yield components in beans grown under no-tillage systems. The experimental […]