Revista Brasileira De Herbicidas 2001; 2(1-2): 31-36
Evaluation of the efficacy of glyphosate+carfentrazone-ethyl on desiccation of weeds in soybean
A test was conducted in Chapadão do Céu city, state ofGoiás, to evaluate the biological efficacy ofa tank mixture of glyphosate + carfentrazone-ethyl, comparing it with glyphosate + 2,4-0 on the desiccation ofweeds in a soybean plantation. The experimental design adopted was that ofrandom blocks, with four replications and nine treatments, as follows: glyphosate (720 and 1080 g/ha), glyphosate + 2,4 -O (720+670 and 1080+402 g/ha), glyphosate + carfentrazone-ethyl (360+30, 720 + 25 and 1080 + 20 g/haj.and 2,4-D (670 g/ha), as wel! as a control treatment. The vegetative cover ofthe are a at application was 95%, with a higher frequency of capim-colchão (Digitaria horizontalis), picão-preto (Bidens pilosa), guanxuma-preta (Sida rhombifolia), guanxuma-branca (Sida cardifolia) and. in lower numbers, erva-quente (Spermacoce latifolia). The evaluations were carried out at 8, 18 and 28 days after treatrnent, adopting a percentual scale in which zero meant no control and one hundred corresponded to total control. The combination ofglyphosate + carfentrazone-ethyl (720+25 and 1080+20 g/ha) caused efficient control of D. horizontalis, B. pilosa, S. cordifolia, S. rhombifolia and Spermacoce latifolia. Glyphosate -i- 2,4-D (720+670 and 1080+402 g/ha), caused efficient control ofweeds, except Spermacoce latifolia. which was satisfactorily control!ed. Glyphosate (720 and 1080 g/ha) was efficient for weed control, except Spermacoce latifolia, whose control was deficient. The hercicide 2,4- D (670 g/ha), caused low levei control of D. horizontalis, satisfactory control of Spermacoce latifolia and efficient control of the other species. A substitution ofthe herbicide 2,4-D by carfentrazone-ethyl in cornbination with glyphosate is possible for the desiccation of weeds in no till plantations.
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