Effect of water volume and water quality on the efficacy of glyphosate on some important weed species in Turkey

The effect of spray water volume and water quality on the performance of three Roundup formulations were investigated in pot experiments to observe whether these factors influence the efficacy of herbicide on three important weed species occurring in Turkey. Sorghum halepense, Cyperus rotundus and Portulaca oleracea were used in the experiments. All Roundup formulations were applied at three different doses with two water volume rates (200 and 600 l/ha) and three different water qualities (clean water, clean water + CaCl2 to simulate hard water and water of Büyük Menderes River). Experiments were carried out at the research station of Adnan Menderes University in the Aydin province of Turkey and replicated twice. Results of the studies showed that the performance of Roundup on weeds was not influenced by herbicide formulation, but significantly affected by water volume as well as water quality. However, the effect of these factors was variable depending on the weed species and the applied herbicide dose. Significant differences were observed mostly at reduced doses more apparently in the case of more sensitive weed species such as P. oleracea and S. halepense. C. rotundus was more tolerant against herbicide so that an influence of investigated factors on the efficacy was observed even with the recommended dose. In general, low volume treatments (200 l/ha) provided significantly higher weed control. Similarly, clean water improved the effectiveness of the herbicide on weeds. These results suggest that using clean spray water and low volume treatments improve the efficacy of glyphosate at the recommended and reduced rates depending on the sensitivities of weed species. Keywords: Cyperus rotundus, formulation, Portulaca oleracea, Sorghum halepenseEinfluss von Wassermenge und -qualität auf die Wirksamkeit von Glyphosat bei wichtigen Unkrautarten in der TürkeiMit Gefäßversuchen wurde der Einfluss von Wassermenge bzw. -qualität auf die Wirksamkeit von drei verschiedenen Roundup-Formulierungen bei wichtigen Unkrautarten in der Türkei untersucht. Sorghum halepense, Cyperus rotundus und Portulaca oleracea wurden bei den Experimenten verwendet. Alle Formulierungen wurden mit drei Aufwandmengen aufgebracht, jede mit 2 verschiedenen Wassermengen (200 und 600 l/ha) und bei drei verschiedenen Wasserqualitäten (reines Wasser, reines Wasser + CaCl2, um die Wasserhärte zu steigern, und Wasser aus dem Büyük Menderes Fluss). Die Versuche wurden am Forschungszentrum der Adnan Menderes Universität in Aydin, Türkei, durchgeführt und zweimal wiederholt. Die Ergebnisse zeigten, dass die Wirksamkeit von Roundup auf die Unkräuter nicht von der Formulierung beeinflusst wurde, aber der Einfluss von Wassermenge bzw. -qualität war signifikant. Jedoch waren die Einflüsse dieser Faktoren von der Unkrautart bzw. von den Aufwandmengen abhängig. Erhebliche Unterschiede wurden bei den reduzierten Aufwandmengen und bei den sensitiveren Arten beobachtet, wie z. B. P. oleracea und S. halepense. C. rotundus war gegenüber dem Herbizid unempfindlicher, so dass die untersuchten Faktoren sogar bei den empfohlenen Aufwandmengen keine Unterschiede der Wirkung verursachten. Im Allgemeinen lieferten Behandlungen mit niedriger Wassermenge signifikant höhere Bekämpfungsgrade. Reines Wasser erhöhte ebenfalls die Wirkung des Herbizids auf die Unkräuter. Aus diesen Ergebnissen geht hervor, dass die Wirksamkeit von Glyphosat bei Anwendung mit reinem Spritzwasser und verringertem Wasseraufwand bei den empfohlenen bzw. reduzierten Aufwandmengen in Abhängigkeit von der Empfindlichkeit der Unkrautarten verbessert wird.Stichwörter: Cyperus rotundus, Formulierung, Portulaca oleracea, Sorghum halepens

Target site mutation and reduced translocation are present in a glyphosate-resistant Lolium multiflorum Lam. biotype from Spain

The resistance mechanism of a glyphosate-resistant Lolium multiflorum Lam. biotype collected in Córdoba (Southern Spain) was examined. Resistance Factor values at three different growth stages ranged between 4.77 and 4.91. At 96 hours after treatment (HAT) the S biotype had accumulated seven times more shikimic acid than the R biotype. There were significant differences in translocation of 14C-glyphosate between biotypes, i.e. at 96 HAT, the R biotype accumulated in the treated leaf more than 70% of the absorbed herbicide, in comparison with 59.21% of the S biotype; the R biotype translocated only 14.79% of the absorbed 14C-glyphosate to roots, while in the S population this value was 24.79%. Visualization of 14C-glyphosate by phosphor imaging showed a reduced distribution in the R biotype compared with the S. Glyphosate metabolism was not involved in the resistance mechanism due to both biotypes showing similar values of glyphosate at 96 HAT. Comparison of the EPSPS gene sequences between biotypes indicated that the R biotype has a proline 182 to serine amino acid substitution. In short, the resistance mechanism of the L. multiflorum Lam. biotype is due to an impaired translocation of the herbicide and an altered target site. © 2012 Elsevier Masson SAS.This research was funded by the firm Monsanto and by Spain's MICINN (Project AGL2010-16774). Javier Gil-Humanes acknowledges financial support from the I3P Program from the Consejo Superior de Investigaciones Científicas, which is co-financed by the European Social Fund.Peer Reviewe

Results from ten years of post-market environmental monitoring of genetically modified MON 810 maize in the European Union.

In European regulations for the deliberate release into the environment of genetically modified organisms (GMO), the objective of General Surveillance in Post-Market Environmental Monitoring is defined as the identification of the occurrence of adverse effects of the GMO or its use which were not anticipated in the environmental risk assessment (ERA). Accompanying the commercial cultivation in the EU of maize event MON 810, General Surveillance was implemented by Monsanto, the authorization holder, on a voluntary basis. We carried out a statistical analysis on the pooled results of ten years of farmer questionnaires, which were a part of this General Surveillance, amounting to 2,627 farmer fields in eight European countries in the period 2006-2015. This analysis did not reveal any unexpected adverse effects associated with the cultivation of MON 810. Results from farmer questionnaires confirmed that the cultivation of MON 810 resulted in a significant reduction in the use of pesticides, efficient protection against the target pests, and healthier, higher yielding crops compared to conventional maize. MON 810 also had reduced susceptibility to disease and pests when compared to conventional maize. Monitoring characteristics related to environment and wildlife revealed no significant differences between MON 810 and conventional maize. Literature searches, that were also conducted as part of General Surveillance, identified a comprehensive set of publications addressing environmental safety as well as food and feed safety aspects of MON 810. None of the publications indicated any adverse effect of MON 810 that was not anticipated in the initial ERA, nor did they lead to a change in the conclusions of the initial risk assessment that demonstrated the safety of MON 810. The development of resistance by the target pests (Ostrinia nubilalis, ECB and Sesamia nonagrioides, MCB) was the only potential adverse effect identified in the ERA of MON 810 cultivation in the EU. The extensive safety data package for MON 810, the robust weight of evidence demonstrating both its safety and benefits, and the history of safe use of MON 810 for 15 years in the EU, indicates that focussing the General Surveillance of MON 810 on literature searches and farmer complaint systems would be appropriately protective. This will allow the identification of potential adverse effect not anticipated in the initial ERA without the intensive effort and organizational challenges of farmer questionnaires