According to BASF Argentina's technical team, improper weed management can reduce sunflower production. It is estimated that the increasing appearance of Sonchus (Sonchus asper), Nabón (Raphanus sativus), Rama Negra(Conyza spp.), and Yuyo Colorado (Anmaranthus quitensis) in sunflowers has reduced its production by up to 20%. In Argentina, this percentage increases in some areas with tolerant and resistant weeds such as Rama Negra in La Pampa and the province of Buenos Aires and Yuyo Colorado in the north and center of the province of Buenos Aires.
Weeds affecting sunflower cultivation are an important point to consider prior to planting. In general, chemical solutions, such as herbicides before and after planting, are limited due to the low availability of chemical assets compared to the volume of crops.
The technical team of BASF through the Expert Program in Weeds seeks to continue to approach solutions to the weed problems of the sunflower producer. The company has expertise in this area though the technology Clearfield Plus, a system that revolutionized the crop due to the combination of advanced seed technology and prolonged weed control.
Both the Rama Negra and Sonchus appear as the main weeds that are most difficult to control during the cultivation of sunflowers. As their main growing season is spring, Nabo, Nabón, and Yuyo Colorado are presented as other resistant weeds that threaten the sunflower in the provinces of Buenos Aires and La Pampa.
BASF technicians have noted that they are currently working in the main sunflower regions of the country to provide a solution to these weeds, following four steps. The first step is to identify the problem to be able to approach it, then choose the site of action or herbicide that will work best for that weed. The third step is to use sites of action with low risk to generate resistance. The last step is to look for residuality in management strategies for different periods of long fallow, pre-emergence, and post-emergence.