Ryegrass (Lolium multiflorum) is an annual grass, traditionally used as forage that has become weed in crops in the south of Brazil.  It has been observed that there are ryegrass biotypes resistant to glyphosate that survive the application of herbicides that inhibit ALS and ACCase. Therefore, the objective was to evaluate the sensitivity of different ryegrass biotypes to glyphosate, iodosulfuron-methyl and clethodim herbicides. The experiment was carried out in a greenhouse, in randomized blocks, in a triple factorial arrangement with […]

This work was developed with the objective of monitoring the occurrence of glyphosate-resistant biotypes of sourgrass (D. insularis) in Machado, Alpinópolis, Serrania and Divisa Nova, in the south region of Minas Gerais, Brazil. In each area, seeds of at least 20 plants were collected in full physiological maturity stage. For operational reasons, the analysis of different biotypes was divided into two timings, the first held in the second half of 2013 and the second in the first half of 2014. […]

The objective of the present study was to evaluate the confirmation of occurrence of wild poinsettia resistance, coming from Rondônia and Rio Grande do Sul, to herbicides with different mechanisms of action, and to determine the dose of herbicides required for 50% reduction in the dry mass of plants (GR50) and for the control of 50% of these plants in each experimental unit (C50). Therefore, an experiment was conducted over greenhouse conditions, in randomized block design with four replications. The […]

The control of weeds in winter crops is done primarily with ALS-inhibitor herbicides. The intensive herbicide use in areas with wheat has provided selection pressure on R. raphanistrum resulting in biotypes resistant to these herbicides. The objective of this work was to determine the existence of cross and multiple resistance to ALS-inhibitors herbicides and alternatives to chemical control of this weed resistant to metsulfuron methyl. Treatments consisted of R. raphanistrum resistant (biotype R) and susceptible (biotypes S), with 12 herbicides: […]

The frequent use of glyphosate in citrus cropping systems of citrus in Brazil has selected resistant populations of sourgrass (Digitaria insularis) to this herbicide, and it is important to characterize this resistance levels for reasons of rational recommendations for management measures. Thus, an assay was conducted to elaborate comparative dose-response curves between two biotypes sourgrass weed, one resistant (R) and one susceptible (S) to glyphosate. The assay was conducted in a greenhouse from February to May 2012, with five doses […]

The sourgrass (Digitaria insularis) characteristics of aggressiveness and the existence of glyphosate resistant biotypes puts this weed in evidence in the Brazilian agricultural scenario In this regard, the present study aimed at the development and evaluation of strategies for the management of sourgrass (Digitaria insularis) resistant to glyphosate in out-of-season corn crop. The use of paraquat in pre-harvest burn-down of soybean followed by the application of clethodim two days after harvesting soybeans provided flexibility to choose the herbicide used as […]

Weeds from Amaranthus genus may cause major yield losses in economic crops, including cotton, if not controlled properly. In order to avoid it, it’s necessary correct species identification, besides herbicides suitability and recommended doses. The aim of this study was to develop the dose-response curve of ALS enzyme inhibitors herbicides (trifloxysulfuron-sodium and pyrithiobac-sodium) applied in pre emergence conditions becoming possible to verify the control effectiveness over four important species of Amaranthus (A. hybridus, A. viridis, A. lividus and A. deflexus) […]

Herbicides alternatives for controlling sourgrass (Digitaria insularis) weed in infested citrus areas are limited, mainly due to the few options of registered herbicides and by the modalities in that these chemical products are used (directed applications). Thus it is important to evaluate other post-emergence herbicides, to be used in association with glyphosate, for the efficient control of glyphosate-resistant biotype of sourgrass (Digitaria insularis), resistant to glyphosate.  The experiment was conducted in Matão County, Sao Paulo State, in area belonging to […]