Abstract Background Eragrostis plana , introduced from South Africa, is the most important invasive perennial weed in the grasslands of Southern Brazil (“Pampa biome”), becoming a threat in neighboring countries. How temperature, light, and water potential affect seed germination is poorly understood but essential to understand its invasiveness and dissemination. Objective This study characterized the seed germination of E. plana from locations in the Brazilian Bioma Pampa under different conditions. Methods Seed germination was evaluated by using a time-to-event model across a wide range of temperatures (15 to 45C), light (total darkness or 12-h light), and water potentials (0, -0.08, -0.2, -0.25, -0.5, -0.75, -1, and -1.5 MPa). Results E. plana seeds did not germinate below 15C and at water potential lower than -0.75 MPa. Among populations, the highest germination was at 40C (> 90%). The base temperature for germination ranged from 12.3 to 15.6C across populations. E. plana did not germinate more than 40% at 25C, except for one population (Caçapava do Sul), with a germination capacity of 73%. Light is a requirement for a fraction of the seeds as darkness inhibits the germination of a fraction of the seeds as well. Conclusions E. plana could adapt to cooler temperatures, as shown by the ability of the Caçapava do Sul population to germinate at low temperatures. This ability for seed germination help to explain why E. plana has successfully invaded the rangelands of Southern Brazil, spreading around neighboring countries. Management strategies have to be urgently adopted to avoid its dissemination abroad. Africa biome, biome biome”) countries E conditions timetoevent time event 15 (1 45C, 45C C 45C) total 12h h 12 light) 0, 0 (0 0.08, 008 08 -0.08 0.2, 02 2 -0.2 0.25, 025 25 -0.25 0.5, 05 5 -0.5 0.75, 075 75 1, 1 -1 1.5 -1. MPa . MPa) 0.75 -0.7 populations > ( 90%. 90 90% 90%) 123 3 12. 156C 6C 40 25C Sul, Sul) 73 73% well abroad biome” 0.08 00 -0.0 0.2 -0. 0.25 0.5 07 7 - 1. 0.7 9 4 0.0 0. -0

Abstract Background Glyphosate is the most effective herbicide to control the invasive and perennial Eragrostis plana in Southern Brazil. However, one application has not been sufficient to prevent the regrowth of plants.Objective: The aim of this research was to evaluate the efficacy of glyphosate sprayed alone or mixed with fluazifop-p-butyl or flumioxazin on E. plana control and to investigate 14C-glyphosate absorption and translocation. Methods Plants with 2-3 tillers were treated with glyphosate (700 g a.e. ha-1), fluazifop-p-butyl (47 g a.i. ha-1), flumioxazin (100 g a.i. ha-1), glyphosate + fluazifop-p-butyl (700 g a.e. ha-1 + 47g a.i. ha-1), glyphosate + flumioxazin (700 g a.e. ha-1 +100 g a.i. ha-1). Weed control was evaluated visually for 28 d after treatment (DAT) when plants were harvested for shoot dry biomass determination. 14C-glyphosate absorption and translocation were measured at 24 and 72 h after treatment. Results Glyphosate at 700 g a.e. ha-1 controlled E. plana plants at 2-3 tillers. The mixture with fluazifop-p-butyl or flumizin did not significantly increase the level of control (87 and 86% at 7 DAT, respectively) but increased 14C-glyphosate translocation to the roots. Conclusions Glyphosate is effective on E. plana. However, applied with fluazifop-p-butyl could improve the control of this weed, especially when perennial plants of E. plana dominate the field, preventing their fast regrowth.