An experiment was conducted on a Cerrado oxisol during 1996/97. The objective of experiment was to evaluate the effects of diclosulam and metolochlor alone or in combination, in preemergence control of Sida rhombifolia in soybean. The experimental design was a complete randomized block with four replications. Treatrnents were as follows: diclosulam at 25 and 35 g/ha, diclosulam + metolachlor at 25+1200,25+1800,35+1200 and 35+1800 g/ha, metolachlor at 1200,1800 and 2400 g/ha, and a tank mix of chlorimuron + lactofem at 1.5+96 […]

A new and important weed, Me/ampodium perfoliatum, has been growing in soybean plantations in the “Cerrados” of Minas Gerais, BraziI. The objective of this study was evaluate the biological activity and soybean tolerance to chorimuronethyl alone or tank rnixed with other postemergence herbicides. Treatrnents were: chlorimuron-ethyl (12.5 and 15 g/ha) + mineral oil (0.05% v/v), chlorimuron-ethyl + lactofen at 12.5+120 g/ha, chlorimuon-ethyl + fomesafen (12.5 + 150 gIha) + mineral oil (0.1% v/v) chlorimuron-ethyl + imazethapyr at 12.5 + 30 […]

A trial was carried out to test the efficacy of formulations and doses of atrazine + simazine, in post-ernergence on maize (cv. BR-201). The following treatrnents were tested in a sandy Latosoil, in Uberaba, Brazil: Primatop 500 se (atrazine 250g/1 + sirnazine 850 g/l) at the doses of2500, 3000 and 3500 g/ha and Prirnatop 80 PM (atrazine 400 g/I + simazine 400 g/I) at the doses of2400, 3200 and 3600 g/ha, plus mineral oil (0.25% v/v); Triamex se (atrazine 250 […]

Field and laboratory experiments were used to test the effect of selected desiccants on the productivity and quality of soybean seeds, Savana cultivar. ln the field ten treatrnents were arranged in a randomized complete block design, with four replications. Treatrnents were: (1) control (harvested during physiological maturation), (2) glyphosate-360 (0.36 kg/ha), (3) glyphosate-360 (0.72 kg/ha), (4) glyphosate-720 (0.36 kg/ha), (5) glyphosate-720 (0.72 kg/ha), (6) glyphosate-480 (0.36 kg/ha), (7) glyphosate-480 (0.72 kg/ha), (8) paraquat (0.30 kg/ha), (9) diquat (0.30 kg/ha), and […]

The experiment was conducted at the Teaching and Research Farrn of the State University of São Paulo, in Selviria- MS, a region ofCerrados vegetation. The objective ofthe study was to evaluate the selectivity and efficacy ofpreemergence application ofsulflentrazone in soybean. Treatrnents included sulfentrazone at 500,550 and 600 g/ha, sequential postemergence application of imazaquim and clethodim at 140 + 72 g/ha and tank mixed fomesafen + clethodim at 250 + 72 g/ha. A weedy and a weeded control were also included. […]

This work was carried out in the field, in an area of comercial production of soybean seeds, Dokko cultivar, and in the Seed Laboratory ofthe University of Uberlândia, Brazil. In the field the treatrnents were distributed in a factorial arrangement (2 x 4) oftwo rates ofthe desiccant paraquat (0,0 and 0.2 kg/ha) and four harvesting times (at physiological maturation, normal harvesting time, 14 and 28 days after normal harvesting time). In the laboratory a new factor (treated and no treated […]

Mixtures of imidazolinone herbicides were applied in pre and postemergence on a hibrid of maize tolerant to this group, to control Richardia brasiliensis, Acanthospermum australe, Brachiaria decumbens and Spermacoce latifolia. Two experiments were conducted, one in each time of application. ln pre-emergence the following mixtures were tested: imazethapyrl imazapyr (79+26, 90+30, 70+35 and 80+40 g/ha), imazethapyr/imazapic (60+30, 70+35 and 80+40 g/ha), imazapicl imazapyr (68+22, 70+35 and 79+26 g/ha), compared with atrazine/metolachlor (3250 g/ha). The following mixtures were tested in postemergence: […]

The occurrence of resistant weeds is a process ofbiotype selection, with mutant genetic traits, which support applications of certam herbicides to which most of the population are susceptible. Imazethapyr, chIorimuron-ethyl, and oxasulfuron herbicides have the same mode of action; they are inhibitors ofthe acectolactate synthetase enzyme (ALS), which is responsible for the synthesis ofthree essential aminoacids: valine, leucine, and isoleucine. These herbicides are widely recommended and used for controlling Euphorbia heterophylla. However, biotypes of E. heterophylla which are resistant to […]

An experiment was carried out with the objective of evaluating the efficiency of selected herbicides in the desiccation of three plant species in Dourados (MS), Brazil, in 1995/96. A randomized block design was used in three plant species: black oat (Avena strigosa ), millet (Pennisetum typhoydes) and Brachiaria plantaginea, with four herbicides in three rates: paraquat (0.30, 0.40 and 0.60 kg/ha), glyphosate (0.72, 1.08 and 1,44 kg/ha), sulfosate (0.96, 1.44 and 1.92 kg/ha) and glyphosate+2,4-D (0.54+0.67, 0.54+1.0 and 0.54+1.34 kg/ha). […]

Andropogo grass (Andropogon gayanus) is a forage very well adapted to poor pasture soils throughout Cerrados (Brazilian savannas). During the last years, with the expansion of no tillage, specially within the cropping system named “crop/pasture integration”, where glyphosate is the main tool the farmers have to c1ean the fields before planting. Andropogo grass became a problem weed due to its natural resistance to that herbicide. Andropogo leaves are strongly hairy, and this is, probably, the cause of that resistance. The […]

The objective of this trial was to study the mulch retention of the herbicide mixtures imazaquin + pendimethalin and sulfentrazone + metribuzin applied in pre-emergence for soybean under no-tillage system. The experiment was settled in Londrina-PR, Brazil, with black oat (Avena strigosa) mulch. A randomized complete block design was used. The treatrnents comprised the following rates of herbicides: zero, 0.5 N, 1.0 N, 1.5 N and 2.0 N (N=normal rate of the herbicide). ln the present study, N=150 g/ha imazaquin […]

This study was intended to evaluate the selectivity to soybean and efficiency to control Bidens pilosa and Euphorbia heterophylla of tank mixtures of imazethapyr and other broadleaf herbicides. Treatrnents included imazethapyr (100 g/ha), imazethapyr + chlorimuron-ethyl (50+ 10,50+ 12.5 and 60+ 10 g/ha), imazethapyr + lactofen (50+96,50+ 120,60+96,60+ 120 and 12.5+120 g/ha), imazethapyr+oxasulfuron (50+37.5 and 60+37.5 g/ha), chlorimuron-ethyl + lactofen (12.5+120 g/ha), oxasulfuron (45 g/ha), chlorimuron-ethyl (15 g/ha), lactofen (168 g/ha), and weedy and weed free checks. All combinations ofherbicides […]

An experiment was carried out with the objective to evaluate the efficiency and selectivity of lactofen in conbination with other herbicides in the control of weeds and to study the effects of the mixtures on some soybean characteristics. The experimental design was a randomized complete block, with ten treatrnents and four replications. Treatrnents were: oxasulfuron (45 g/ha), oxasulfuron +lactofen (37.5+96.0 and 45.0+96.0 g/ha), c1oransulam-methyl + lactofen (29.4+96.0 and 37.8+96.0 g/ha), and two controls ( with and without hoeing). Ipomoea grandifolia, […]

Lack ofbroadleaf chemical control options in sunflower is a major production problem. An experiment was conducted at Embrapa Soja in Londrina, Paraná State, Brazil, to evaluate broadleafweed control and agronomic efficiency ofpreemergence herbicides applied on clay soil. The treatrnents were: sulfentrazone (350 and 600 g/ha), acetochlor (2100 and 2520 g/ha) and oxyfluorfen (360 and 480 g/ha), weed and hand hoeing treatments. Sulfentrazone applied at 350 g/ha was seletive to sunflower cultivar M 734 and efficient in controlling wild poinsettia tEuphorbia […]