Efficacy, phytotoxicity and economics of different herbicides in aerobic rice

Figures & data

Table I. List of herbicide treatments used in the experiments in off season 2010 and main season 2010/11.

		Application
Label	Treatment	Rate	Time (days after seeding)
T1	Bispyribac-sodium	0.03 kg a.i. ha^−1	10
T2	Bispyribac-sodium fb Bentazon/MCPA	0.03 kg a.i. ha^−1 fb 0.6/0.1 kg a.i. ha^−1	10 fb 40
T3	Cyhalofop-butyl+Bensulfuron	0.1 kg a.i. ha^−1+ 0.06 kg a.i. ha^−1	10
T4	Cyhalofop-butyl+Bensulfuron fb Bentazon/MCPA	0.1 kg a.i. ha^−1+ 0.06 kg a.i. ha^−1fb. 0.6/0.1 kg a.i. ha^−1	10 fb 40
T5	Fenoxaprop-p-ethyl/safener	0.06 kg a.i. ha^−1	10
T6	Fenoxaprop-p-ethyl/safener fb Bentazon/MCPA	0.06 kg a.i. ha^−1 fb 0.6/0.1 kg a.i. ha^−1	10 fb 40
T7	Pretilachlor /safener	0.5 kg a.i. ha^−1	1
T8	Pretilachlor /safener fb Bentazon/MCPA	0.5 kg a.i. ha^−1 fb 0.6/0.1 kg a.i. ha^−1	1 fb. 40
T9	Pretilachlor fb Propanil/Thiobencarb	0.5 kg a.i. ha^−1 fb 1.2/2.4 kg a.i. ha^−1	1 fb 10
T10	Propanil/Thiobencarb	1.2/2.4 kg a.i. ha^−1	10
T11	Propanil/Thiobencarb fb Bentazon/MCPA	1.2/2.4 kg a.i. ha^−1 fb 0.6/0.1 kg a.i. ha^−1	10 fb 40
T12	Quinclorac	0.25 kg a.i. ha^−1	10
T13	Quinclorac fb Bentazon/MCPA	0.25 kg a.i. ha^−1 fb 0.6/0.1 kg a.i. ha^−1	10 fb 40
T14	Season long weed-free	–	–
T15	Season long weedy	–	–
/ means herbicides were formulated as a proprietary mixture,+means that the herbicides were tank-mixed and applied at the same time. All herbicides were applied as per manufacturers’ recommended rates in 300 L of water ha^−1 by knapsack sprayer. fb=followed by.

Table II. Weed composition with summed dominance ratio followed by standard error in off season 2010 and main season 2010/2011 as observed in season-long weedy check.

		Summed dominance ratio
Scientific name	Family name	Off season 2010	Main season 2010/2011
Broadleaf
Alternanthera sessilis (L.) R. Br. Ex DC.	Amaranthaceae	2.33±0.69	1.26±0.26
Cleome rutidosperma DC	Capparidaceae	11.43±3.64	10.04±4.1
Emilia sonchifolia (L.) DC. Ex Wight	Asteraceae	2.43±0.88	0.84±0.19
Euphorbia hirta L.	Euphorbiaceae	1.60±0.58	1.05±0.33
Hedoytis corymbosa (L.)Lam.	Rubiaceae	2.07±0.72	2.08±0.52
Hyptis brevipes Poit	Lamiaceae	0.92±0.25	1.39±0.71
Jussiaea linifolia Vahl	Onagraceae	3.82±1.97	4.73±1.3
Phyllanthus niruri L.	Euphorbiaceae	2.39±0.54	4.25±0.9
Physalis heterophylla Nees	Solanaceae	16.85±4.73	19.26±6.2
Mimosa pudica L.	Fabaceae	3.41±1.10	2.22±0.64
Scoparia dulcis L.	Scrophulariaceae	10.50±4.01	13.41±3.7
Sedges
Cyperus aromaticus	Cyperaceae	1.06±0.21	1.47±0.74
Cyperus rotundus L.	Cyperaceae	11.62±3.27	9.74±2.56
Cyperus sphacelatus Rottb.	Cyperaceae	4.47±1.05	2.25±0.61
Fimbristylis miliacea (L.) Vahl	Cyperaceae	4.05±1.36	5.88±1.95
Grasses
Axonopus compressus (Sw.)Beauv	Poaceae	0.53±0.12	0.32±0.11
Digitaria ciliaris (Retz.) Koel	Poaceae	0.76±0.24	2.67±0.67
Echinochloa colona (L.) Link	Poaceae	4.75±1.25	3.44±1.03
Eleusine indica (L.) Gaertn.	Poaceae	6.59±2.63	7.51±3.25
Leptochloa chinensis (L.) Nees	Poaceae	8.42±3.01	6.19±1.86

Table III. Weed control and phytotoxicity rating of different herbicides using 1 to 5 scales (Okafor 1986).

	Weed control rating			Phytotoxicity rating
	Days after application
Herbicide	7	14	21	7	14	21
Bentazon/MCPA	4	3	1	1	2	1
Bispyribac-sodium	3	2	1	1	2	1
Cyhalofop-butyl+Bensulfuron	3	2	1	1	1	1
Fenoxaprop-p-ethyl/safener	5	4	3	1	1	1
Pretilachlor /safener	1	2	3	2	1	1
Propanil/Thiobencarb	3	2	2	1	1	1
Quinclorac	4	4	3	1	1	1
Weed control rating: 1=excellent/ satisfactory, 2=good, 3 =fair, 4=poor, 5=no/very poor control.
Phytotoxicity rating: 1=very slight injury, 2=slight injury, 3=phytotoxic, 4=severely phytotoxic, 5=100% killed.

Figure 1.  Weed dry weight at different growth stages of rice variety AERON 1 as influenced by weed control treatments (averaged over seasons). T1=Bispyribac-sodium; T2=Bispyribac-sodium fb Bentazon/MCPA; T3=Cyhalofop-butyl+Bensulfuron; T4=Cyhalofop-butyl+Bensulfuron followed by (fb) Bentazon/MCPA; T5=Fenoxaprop-p-ethyl/safener; T6=Fenoxaprop-p-ethyl/safener fb Bentazon/MCPA; T7=Pretilachlor/safener; T8=Pretilachlor/safener fb Bentazon/MCPA; T9=Pretilachlor/safener fb Propanil/Thiobencarb; T10=Propanil/Thiobencarb; T11=Propanil/Thiobencarb fb Bentazon/MCPA; T12=Quinclorac; T13=Quinclorac fb Bentazon/MCPA; T14=Season long weed-free; T15=Season long weedy.

Figure 2.  Weed density at different growth stages of rice variety AERON 1 as influenced by weed control treatments (averaged over seasons). T1=Bispyribac-sodium; T2=Bispyribac-sodium fb Bentazon/MCPA; T3=Cyhalofop-butyl+Bensulfuron; T4=Cyhalofop-butyl+Bensulfuron followed by (fb) Bentazon/MCPA; T5=Fenoxaprop-p-ethyl/safener; T6=Fenoxaprop-p-ethyl/safener fb Bentazon/MCPA; T7=Pretilachlor/safener; T8=Pretilachlor/safener fb Bentazon/MCPA; T9=Pretilachlor/safener fb Propanil/Thiobencarb; T10=Propanil/Thiobencarb; T11=Propanil/Thiobencarb fb Bentazon/MCPA; T12=Quinclorac; T13=Quinclorac fb Bentazon/MCPA; T14=Season long weed-free; T15=Season long weedy.

Table IV. Grain yield, weed inflicted relative yield loss and yield increase over control of rice variety AERON 1 due to different weed control treatments (averaged over seasons).

Treatment	Grain yield (t ha^−1)	Relative yield loss (%)	Yield increase over control (%)
T1	3.09de	16.03	197.03
T2	3.25b-d	11.68	212.53
T3	3.14c-e	14.67	201.85
T4	3.49ab	5.16	235.83
T5	2.106i	41.58	107.69
T6	2.62f-h	28.80	151.92
T7	2.55gh	30.98	145.19
T8	2.87ef	22.28	175.96
T9	3.42a-c	7.06	228.84
T10	3.14c-e	14.67	201.92
T11	3.29b-d	10.59	216.34
T12	2.42hi	34.24	132.69
T13	2.75hg	25.27	164.42
T14	3.68a	0.0	253.84
T15	1.04j	72.0	0.0
T1=Bispyribac-sodium; T2=Bispyribac-sodium fb Bentazon/MCPA; T3=Cyhalofop-butyl+Bensulfuron; T4=Cyhalofop-butyl+Bensulfuron followed by (fb) Bentazon/MCPA; T5=Fenoxaprop-p-ethyl/safener; T6=Fenoxaprop-p-ethyl/safener fb Bentazon/MCPA; T7=Pretilachlor/safener; T8=Pretilachlor/safener fb Bentazon/MCPA; T9=Pretilachlor/safener fb Propanil/Thiobencarb; T10=Propanil/Thiobencarb; T11=Propanil /Thiobencarb fb Bentazon/MCPA; T12=Quinclorac; T13=Quinclorac fb Bentazon/MCPA; T14=Season-long weed-free; T15=Season long weedy.
Within a column, means sharing same alphabets are not significantly different at p=0.05 probability level according to LSD test.

Figure 3.  Relationship between weed control efficiency and grain yield of rice variety AERON 1.

Table V. Cost effectiveness of different herbicide treatments (averaged over seasons).

	Ringgit Malaysia ha^−1
Treatment	Herbicide cost	Laborer cost for spraying/weeding	Total cost	Gross income	Net benefit
T1	110+114	50	274	3140	2866
T2	110+114+60	50+50	384	3490	3106
T3	120	50	170	3090	2920
T4	120+60	50+50	280	3250	2970
T5	210	50	260	2420	2160
T6	210+60	50+50	370	2750	2380
T7	154	50	204	2150	1946
T8	154+60	50+50	314	2620	2306
T9	252	50	302	3140	2838
T10	252+60	50+50	412	3290	2878
T11	117	50	167	2540	2373
T12	117+60	50+50	277	2860	2583
T13	117+252	50+50	469	3420	2951
T14	0.0	2500	2500	3680	1180
T15	0.0	0.0	0.0	1030	1030
T1=Bispyribac-sodium; T2=Bispyribac-sodium fb Bentazon/MCPA; T3=Cyhalofop-butyl+Bensulfuron; T4=Cyhalofop-butyl+Bensulfuron followed by (fb) Bentazon/MCPA; T5=Fenoxaprop-p-ethyl/safener; T6=Fenoxaprop-p-ethyl/safener fb Bentazon/MCPA; T7=Pretilachlor/safener; T8=Pretilachlor/safener fb Bentazon/MCPA; T9=Pretilachlor/safener fb Propanil/Thiobencarb; T10=Propanil/Thiobencarb; T11=Propanil/Thiobencarb fb Bentazon/MCPA; T12=Quinclorac; T13=Quinclorac fb Bentazon/MCPA; T14=Season-long weed-free; T15=Season long weedy.
RM=Ringgit Malaysia. 1 US$ =3 Ringgit Malaysia (RM) (approx).
Market price of commercial herbicides: Sofit N300 EC=70 RM L^−1, Halop 100 EC= 110RM L^−1, Tekong =19 RM 100 g^−1, Nominee 100 SC=98 RM 250 mL^−1, Satunil=42 RM L^−1, Rumpas M=43 RM 250 mL^−1, Quintox=42 RM 100g^−1 and Basagran M60=38 RM L^−1.
Manual weeding cost: 100 laborers ha^−1 for 2 weedings @ 25 RM laborer^−1 day^−1, Herbicide application cost: 2 laborers^−1 ha^−1 round^−1 @ 25 RM laborer^−1 day^−1, Market price of paddy: 1000.00 RM t ha^−1, Gross income=paddy yield (t ha^−1)×market price (RM t ha^−1), Net benefit=gross income – total weeding cost.