Weeds emergence maps – 2009/2010 season

(click on picture to see maps)

Johnson grass	Crabgrass	Goose grass	Barnyard grass	Knotroot foxtail	Broadleaf signalgrass

Two additional weeds ―apart from Sorghum halepense, Digitaria sanguinalis, Eleusine indica, Echinochloa colonum and Setaria geniculata have been added to the list in this third season: they are Cynodon dactylon and Urochloa platyphylla. Maps have been designed to show the extent to which the seedlings of such weeds emerge in the fields and how this is related to the climate in the Pampean region. Moreover, the difference between the emergence of Johnson grass growing from seed and the emergence of that growing from rhizomes has been stated.

In addition, it is essential to report to the Argentine National System of Surveillance and Monitoring of Agricultural Pest (SINAVIMO) as soon as resistance signals of glyphosate-resistant Johnson grass are suspected. It is also very important to assess the distribution as well as the evolution of this case. As a result, preventive and management strategies may be developed and carried out; this will also warn all the involved parties of the problem.

In case specimens of resistant Johnson grass are detected, please download the Report Sheet (here) and email it to: aleporesistente@senasa.gov.ar

Basis for the system
Because direct sowing has been undoubtedly beneficial to the preservation of the soil as a natural resource and of water accumulation ―a main aspect of production systems on non-irrigated land―, its importance has grown significantly. To a great extent, the success of this sowing system relies on an adequate management of these weeds; this implies the intensive, continuous use of herbicides. In this present scenario, only a few active principles are uniformly used several times a year. The volume of glyphosate, which is one of the most widely used herbicides in the direct sowing systems of Argentina, amounts to more than 250 million liters ―i.e., $550 million― a year. Nowadays, there are no tools for planning when to apply such products. As a consequence, decision-making has up to now been absolutely empirical and depends on other (non-biological) variables. In addition, from the point of view of the marketing of grains and seeds, such a system proves very important for minimizing potential problems, whether they are a result of the presence of alien material or of a failure to comply with all the phytosanitary requirements for the products intended for exportation.

Goal
The goal of this project is to provide a tool which is accessible to all the public and which, on the basis of climatic data and a proper management of the site, will enable to accurately predict, up to the given date, the quantity of specimens of five species (namely, Sorghum halepense, Digitaria sanguinalis, Eleusine indica, Echinochloa crus-galli and Setaria geniculata) that are emerging in such site, assuming, of course, that there are seeds in the soil bank of the site. This tool, however, is supplementary and does not replace the monitoring process of each field, which is a necessary, permanent and systematic procedure.

What are the benefits of an emergence of field weeds alert and prediction system?

• The system enables a proper selection of herbicides in relation to when it should be applied (PS, PREEM, POST);
• It enables a proper selection of the herbicide in relation to its residuality (i.e., crops, fallow);
• It enables to choose the best date for control (in the case of post-emergent herbicides)
• It enables to decide the most adequate dose (dose-response);
• It enables a proper management (logistics – timing)

Vision
The development, validation and the implementation of a system towards weeds emergence prediction or alert and the temporal dynamics of weeds will help improve the use of herbicides and the logistics of herbicide sprayings, as well as obtain extra financial and environmental benefits.

This project is based on extensive research and empirical work that have been going on for six years. It is worth mentioning that such information is constantly validated and amended so as to provide a scientific grounding to a process where different biological, environmental and management aspects work together.

Project leader: Eduardo S. Leguizamón, Agricultural Engineer

Participating technicians:
 Technicians participating in the research project for the development of prediction models (2000-2007)
 Technicians participating in the implementation of the alert system (2007-2008)
 Technicians participating in the validation of the prediction models
 Technicians participating in the compilation of meteorological data.

Coordination: National Service for Agrifood Health and Quality (SENASA – Central headquarters - Bureau of Surveillance and Monitoring - Argentine National System of Surveillance and Monitoring of Agricultural Plagues (SINAVIMO)

Director: Pablo Cortese, Agricultural Engineer.

Coordination: Cecilia García Sampedro, Agricultural Engineer; María Trinidad Berbery, Agricultural Production Engineer

Weeds comprised in this project::

• Sorghum halepense (Johnson grass)

Season 2007-2008
Season 2008-2009
Season 2009-2010

• Eleusine indica (goose grass)

Season 2007-2008
Season 2008-2009
Season 2009-2010

• Echinochloa colonum (Capín)

Season 2007-2008
Season 2008-2009
Season 2009-2010

• Setaria geniculata (knotroot foxtail)

Season 2007-2008
Season 2008-2009
Season 2009-2010

• Urochloa platyphylla (broadleaf signalgrass)

Season 2007-2008
Season 2008-2009

• Digitaria sanguinalis (crabgrass)

Season 2007-2008
Season 2009-2010
Season 2009-2010

Links:

http://www-aes.tamu.edu/mary/wdid.htm 

http://weeds.cropsci.vivc.edu/weedid.htm 

http://weedid.aces.vivc.edu

http://invader.dbs.umt.edu/

http://www.nawma.org/ 

http://www.fws.gov/ficmnew/index.html