ALTERNATIVES OF MANEGMENT TO THE POPULATIONS OF Bidens pilosa AND Bidens subaltenans RESISTANTTO THE ALS INHIBITORS HERBICIDES

Abstract

Resistant populations of Bidens pilosa and Bidens subalternans to the ALS inhibitors herbicides become more frequent at the soybeans fields from middle-west, that is due the intensive use of ALS herbicides, aimed to obtain data that can contribute on the choose of the best alternative of control for those populations. A trial in a green-house, in Piracicaba, SP, to test many herbicides as an possible alternatives of management of those resistant weeds. Initially we used two populations of Bidens pilosa and two populations of Bidens subalternans, one of these was resistant and the other was susceptible to each species. The herbicides treatments were sprayed when the plants showed up 2 to 4 leaves, chlorimuron (17,5 g.i.a.ha-1); imazethapyr (100 g.i.a.ha-1); chlorimuron + lactofen (10+96 g.i.a.ha-1); clomazone (800 g.i.a.ha-1 ); sulfentrazone (500 g.i.a.ha-1 ); glyphosate (600 g.i.a.ha-1); flumicorac (30+30 g.i.a.ha-1); flumicorac + bentazon (40+480 g.i.a.ha-1); bentazon (720 g.i.a.ha-1 ); fomesafen (250 g.i.a.ha-1 ); acifluorfen + bentazon (204+480 g.i.a.ha-1 ); lactofen (150 g.i.a.ha-1); metribuzin (480 g.i.a.ha-1); diclosulam + clomazone (30,24+800 g.i.a.ha-1 ); cloramsulan + lactofen (30,24+150 g.i.a.ha-1); lactofen (72+72 g.i.a.ha-1); lactofen (144 g.i.a.ha-1); nicosulfuron (50 g.i.a.ha-1 ). We analyzed the percentage of control at 7, 14, 21 and 28 days after the application (DAA) and dry weight at 28 DAA. Applied the test F over the variance analyses followed by tukey test at 5%. The herbicides chlorimuron, imazethapyr and nicosulfuron showed up poor control to all resistant populations, being more inefficient on Bidens subalternans than Bidens pilosa. The other herbicides treatments had a very good efficacy to all populations.