Effective weed control in perennial crops is a challenge due to the limited availability of registered herbicides and herbicide resistance. The objective of the study was to evaluate the efficacy of the herbicide GF-2581 (penoxsulam + florasulam) on broadleaf weeds in comparison with other commonly used herbicides. Field trials were conducted in olives, in Etoloakarnania (Agrinio region) for two years (2012 and 2013). Efficacy assessments were made at 30, 60, 90 and 120 days after treatment. The GF-2581 formulation provided excellent control of a broad spectrum of broadleaf weed species. The long-term control of Sonchus oleraceous, Conyza canadensis and Stellaria media, provided by GF-2581 during the growing season was significantly greater than that using flumioxazin. When combined with glyphosate or diquat, the level of control of these three weeds was improved. The GF-2581 agent applied pre-emergence followed 14 days later by application of glyphosate provided 100% control in 2012. Lower efficacy levels were observed in 2013 and may have been the result of higher rainfall when compared to 2012. GF-2581 is an effective herbicide product to control broadleaf weeds, as a part of integrated weed control management strategies in olives.

Abstract:Reduced efficacy of several herbicides on some important broadleaf weeds might be due to the extended use of the specific active ingredients. In our study, field experiments were carried out in Greece in 2014 and 2015 to study the efficacy of the herbicide Lancelot 450 WG (aminopyralid 300 g ai/kg + florasulam 150 g ai/kg) compared to other herbicides against broadleaf weeds in maize. Effects on crop yield and quality parameters (nitrogen, protein, and oil content) were also evaluated. Our results showed that the ready mixture of aminopyralid + florasulam at the recommended dose of 33 g/ha resulted in a very good control of Xanthium strumarium, Amaranthus retroflexus, Cirsium arvense, and Solanum nigrum even at 28 DAT, providing a long-term effect. Efficacy of the specific mixture was also very efficient against the invasive weed species Physalis angulata L. Moreover, there were not any significant differences between the two doses of Lancelot 450 WG (33 and 66 g/ha) and Callisto 10 SC at double the recommended dose (1500 mL/ha) regarding yield of maize, with untreated plots and treated with Callisto 10 SC at the recommended dose (750 mL/ha) showing significantly lower yields. It has to be noted that even double the recommended dose of Lancelot 450 WG (66 g/ha) was highly selective to the crop, without any adverse effects on yield and quality parameters. Conclusively, Lancelot 450 WG could be proposed as a very efficient herbicide for the control of the major broadleaf weeds and alien, invasive species in maize crop.