Effect of Growth Stage on the Efficacy of Postemergence Herbicides on Four Weed Species of Direct-Seeded Rice

Table 1

Effect of postemergence herbicides on seedling survival (%) of barnyardgrass, Chinese sprangletop, junglerice, and southern crabgrass when sprayed at their four-, six-, and eight-leaf stage.

Weed control treatment	Rate	Seedling survival
		Four-leaf	Six-leaf	Eight-leaf
	g ha^−1		%
Barnyardgrass
Untreated control	0	100	100	100
Bispyribac-sodium	30	19	94	100
Fenoxaprop-p-ethyl + ethoxysulfuron	45	13	56	80
Penoxsulam + cyhalofop	72	63	83	100
LSD0.05		17	22	12
Chinese sprangletop
Untreated control	0	100	100	100
Bispyribac-sodium	30	91	99	100
Fenoxaprop-p-ethyl + ethoxysulfuron	45	0	1	1
Penoxsulam + cyhalofop	72	0	2	61
LSD0.05		13	3	17
Junglerice
Untreated control	0	100	100	100
Bispyribac-sodium	30	4	0	48
Fenoxaprop-p-ethyl + ethoxysulfuron	45	6	41	89
Penoxsulam + cyhalofop	72	16	53	89
LSD0.05		11	20	18
Southern crabgrass
Untreated control	0	100	100	100
Bispyribac-sodium	30	9	82	100
Fenoxaprop-p-ethyl + ethoxysulfuron	45	0	7	65
Penoxsulam + cyhalofop	72	91	100	100
LSD0.05		14	15	17