Population genomics of Digitaria insularis from soybean areas in Brazil.

Background: Digitaria insularis is a weed species that has gained considerable importance in Brazil's soybean production areas that rely on glyphosate-resistant cultivars. Herbicide-resistant weed populations of this species have been reported in many regions in Brazil, first in the south, followed by later reports in the north. We hypothesized that the spread of herbicide-resistant D.

Monitoring Glyphosate- and Chlorimuron- resistant Conyza spp. Populations in Brazil.

Conyza species are important weeds in global agriculture, especially due to their capacity to evolve resistance to multiple herbicide mechanisms of action. We aimed to evaluate the frequency and distribution of resistance to glyphosate and chlorimuron-ethyl in Conyza spp. populations from Brazil.

Confirmation and mechanism of glyphosate resistance in tall windmill grass (Chloris elata) from Brazil.

Background: Overreliance on glyphosate as a single tool for weed management in agricultural systems in Brazil has selected glyphosate-resistant populations of tall windmill grass (Chloris elata Desv.).

Results: Two C.

Glyphosate sustainability in South American cropping systems.

South America represents about 12% of the global land area, and Brazil roughly corresponds to 47% of that. The major sustainable agricultural system in South America is based on a no-tillage cropping system, which is a worldwide adopted agricultural conservation system. Societal benefits of conservation systems in agriculture include greater use of conservation tillage, which reduces soil erosion and associated loading of pesticides, nutrients and sediments into the environment.

Alternative herbicides to manage Italian ryegrass (Lolium multiflorum lam) resistant to glyphosate at different phenological stages.

During the growing season of 2002--2003, field and greenhouse experiments were conducted with the objective of evaluating the influence of Italian ryegrass phenological stages and management alternatives on the control of resistant biotypes to glyphosate. Three field experiments were conducted in Lagoa Vermelha, RS, Brazil and glyphosate was applied alone and in combinations with alternative herbicides. Two greenhouse experiments were also conducted at the Department of Crop Science, ESALQ/USP, Piracicaba, SP, Brazil.

Using thermal units for estimating critical period of weed competition in off-season maize crop.

Brazilian off-season maize production is characterized by low yield due to several factors, such as climate variability and inadequate management practices, specifically weed management. Thus, the goal of this study was to determinate the critical period of weed competition in off-season maize (Zea mays L.) crop using thermal units or growing degree days (GDD) approach to characterize crop growth and development.