HERBICIDE COMBINATION FOR CONTROL OF COMPLEX WEED FLORA IN TRANSPLANTED RICE

Herbicide combination for control of
complex weed flora in transplanted rice
Presenter :-
Jai Prakash
Id. No. 0812
Ph. D.(Agronomy)
Department of Agronomy

Introduction
• Rice is the global grain cultivated in about 89 country.
• Rice (Oryza sativa L.) is a staple food of more than 60% of world population.
• Rice occupies a pivotal place in Indian Agriculture and is a staple food for
more than 70% of population. It is grown on an area of 43.42 m. ha with total
production of 105.24 mt. with the productivity of 24.23 q /ha.(Anonymous -
2014)
• Globally rice production must increase by 36% by 2025 to feed 4 billion rice
consumers.
• Good source of energy contain about 70% carbohydrate and 6-7% protein.
• Weeds emerge soon after rice is transplanted and if not controlled in early
stages of crop growth these may cause reduction in yield varying from 10 to
40% depending upon intensity and kind of weeds present in area.

43.94
30.58
13.83
12.37 11.77
7.9 7.5
4.74
3.1 2.7
26.73
0
5
10
15
20
25
30
35
40
45
50
area Mha
India
27%
China
18%
Indonesia
8%
Thiland
7%
Bangladesh
7%
Vietnam
5%
Burma
5%
Philippines
3%
Combodia
2%
Pakistan
2% Others
16%
Share %
Country wise area and percent share in paddy crop

205.2
159.2
71.27
51.5
44.03
36.06
28.76
18.43
11.78 10.75
103.9
0
50
100
150
200
250
Rice production M.T.
China
27%
India
21%
Indonesia
10%
Bangladesh
7%
Vietnam
7%
Thailand
5%
Burma
4%
Philippines
2%
Brazil
2% Japan
1%
Others
14%
Share %
Country wise production (M.T.) and percent
share of rice

44.85
102.17
95.29
86.23
81.38 78.55 77.14 77.11 76.5 75.43 75.38
67.1
36.23
0
20
40
60
80
100
120
Average productivity (q/ha)
Source – FAOSTAT (Food and Agriculture Organization of United State -2013)
Country wise average productivity (q/ha) of rice (2013).

S. No. State Area( M ha) Production(M.T.) Average Yield(Kg/ha)
1. West Bengal 5.44 15.02 2760
2. Uttar Pradesh 5.86 14.42 2460
3. Andhra Pradesh 3.63 11.51 3173
4. Punjab 2.85 11.37 3998
5. Orissa 4.02 7.30 1814
6. Chhattisgarh 3.78 6.61 1746
7. Tamilnadu 1.49 4.05 2712
8. Bihar 3.30 7.53 2282
9. Assam 2.49 5.13 2061
10. Haryana 1.22 3.98 3272
11. Karnataka 1.28 3.36 2632
12. Maharashtra 1.56 3.06 1963
13. M.P. 1.88 2.77 1474
14. Jharkhand 1.41 3.16 2238
15. Gujarat 0.70 1.54 2198
16. Kerala 0.20 0.51 2577
17. Other 1.64 3.92
Source – Directorate of Economics and statistics, Deptt. Of agri. and cooperation (2012-13)
State wise area, production and productivity of rice in India (2012-2013)

Area, production and Productivity of rice during (2001-2013)
In Uttar Pradesh
Year Area (m ha) Production (mt) Productivity (qt/ha)
2001-02 6.07 12.85 21.17
2002-03 5.21 9.59 18.40
2003-04 5.72 12.48 21.81
2004-05 5.34 10.75 18.11
2005-06 5.57 11.12 19.96
2006-07 5.82 10.88 18.69
2007-08 5.69 11.73 20.62
2008-09 6.01 13.05 21.71
2009-10 5.14 10.71 20.81
2010-11 5.63 11.94 21.20
2011-12 5.95 13.53 23.58
2012-13 5.99 14.55 24.48
Source - Rice knowledge management portal -2013

13%
75%
8%
4%
Consumption of pesticide in India
Herbicide
Insecticide
Fungicide
other
43%
31%
21%
5%
Consumption of pesticides in the
world
Herbicide
insecticide
Fungicide
Other
Consumption of different pesticides
Source - Yaduraju,2006

Herbicide use in crops - India
74%
7%
6%
4% 9%
Cereals
Non selective fields
Plantation crop
Soyabean
Others
Source - Yaduraju,2006

11
Key components for a good crop of TPR
• Plant stand
• Water management
• Nutrient management
• Weed management

Why Control Weeds?
• Prevent yield loss due to crop weed competition
• Maintain purity and market price of harvested grain
• Prevent build-up of weed seeds in soil
• Prevent weeds that may attract insects or rodents
(rats) or act as a host for diseases
• Prevent clogging of field irrigation channels and
facilitate water flow
• Reduce time and cost of land preparation and weeding
operations

Estimated yield losses caused by weeds in different methods
of rice establishment in India
Method of Rice
establishment
% reduction in yield due to
weeds
Reference
TPR 12 to 69.5% Singh et al., 2011
Wet-seeded Rice 85% Singh et al., 2011
Upland direct-seeded
Rice
93.6% Ladu, and Singh, 2006
Dry-seeded rice zero
tillage
98% Singh et al.,2011
Dry-seeded rice 34.4 to 72.6% Moorthy and Saha, 2001
Upland Rice 97.2% Singh et al.,1988
Rice- wheat cropping
system
13.1 to 22.4% Singh et al.,2005

Other ill effects of weeds
• Clog irrigation and drainage channels
• Lengthens time span in land preparation
• Act as alternate host
• Reduce the quality of harvested produce
• Hindrance in harvesting and threshing
management
• Decrease WUE and FUE
• Increase cost of cultivation

Problematic weeds of transplanted rice
Annual grassy weeds
1. Echinochloa colona (Jungle rice/Awn less barn yard grass)
2. Echinochloa crus-galli (barnyardgrass)
3. Eleusine indica (Goose grass)
4. Leptochloa chinensis (Red spangle top) / China grass)
5. Ischaemum rugosum (Wrinkle grass/Saw grass)
Annual Cyperaceous weeds:
1. Cyperus iria (Umbrella sedge)
2. Cyperus rotundus (Purple nut sedge)
3. Cyperus difformis (Small flower umbrella Plant)
4. Cyperus esculentus (Yellow nut grass)
Annual broad leaf weeds
1. Eclipta alba (false daisy /Jal Bhangra)
2. Ammania baccifera (Fire leaf)
3. Sphenoclea Zeylanica (Goose weed)
4. Caesulia axillaries (Caesulia)
5. Ludwigia parviflora (water purslane)
6. Commelina benghalensis (Day flower/Tropical spider

Chemical method
• Use of herbicides
Pre-plant incorporation Pre-emergence Post-emergence

Timing is critical in rice …….
First 40 Days are the most critical in the life cycle of transplanted Rice plants
In rice the flood provides over 50% of weed control. It will keep
weeds from germinating, but really won't kill weeds that are already
growing …
Grass cannot be allowed to get bigger than the 5 leaf stage.
40 Days

Herbicide and herbicide combination
Mixtures of selected herbicides offer several advantages over the use
of a single herbicide, including
(a) a reduction in cost of cultivation by saving time and labour,
(b) a reduction in soil compaction by eliminating multiple field
operations,
(c) an increase in the spectrum or range of weeds controlled or an
extension of weed control over a longer period of time,
(d) an improvement in crop safety by using minimum doses of
selected herbicides applied in combination rather than a single
high dose of one herbicide,
(e) a reduction in crop or soil residues of persistent herbicides by
using minimum doses of such herbicides, and
(f) a delay in the appearance of resistant weed species to selected
herbicides

Types of herbicide combination

Objective:
The optimum herbicide combinations would be
those that exhibit enhanced activity on target
weed species and decreased toxicity on crops
(increased selectivity).
This is difficult to predict since the behaviour of
each single herbicide in the mixture is often
affected by the presence of the other(s) and the
activity of the mixture may also vary considerably
depending on plant species, growth stage, and
environmental conditions.
………..continued

Treatments Dose (g a.i. ha-1) 30 DAT 60 DAT
Weed density Dry matter Weed density Dry matter
Imazosulfuron 30 3.71 2.05 3.57 5.10
Imazosulfuron 40 3.39 1.94 3.60 5.03
Imazosulfuron 50 3.29 1.92 3.43 5.02
Imazosulfuron 60 3.36 1.86 3.33 4.99
Imazo+Anilofos 40+250 3.70 1.43 3.17 4.68
Imazo+Anilofos 30+300 2.53 1.20 2.76 4.37
Imazo+Anilofos 40+300 1.55 1.10 2.39 4.11
Imazo+Pretilachlor 30+600 2.63 1.18 3.08 3.99
Anilofos 400 2.18 0.87 2.81 3.45
Pretilachlor 750 2.63 1.07 2.68 4.07
Weed Free 0.00 0.00 0.00 0.00
Weedy 4.38 2.27 4.50 6.22
C.D. at 5% 0.21 0.33 0.17 0.29
Table 1. Effect of tank mix herbicide on weed density (No.m-2) and total dry matter of weeds
(gm-2) at different stage of crop growth.
Source – Manhas et al. 2012 (Uttarakhand)

Treatments Dose (g ha-1) 90 DAT at harvest 60 DAT
Weed density Dry matter Weed density Dry matter WCI
Imazosulfuron 30 3.55 6.27 3.28 6.37 71.1
Imazosulfuron 40 3.55 6.07 3.46 6.28 69.7
Imazosulfuron 50 3.49 5.85 3.33 5.94 67.8
Imazosulfuron 60 3.27 5.71 3.13 5.84 69.8
Imazo+Anilofos 40+250 3.32 6.10 2.78 5.94 78.3
Imazo+Anilofos 30+300 2.76 5.64 2.70 5.60 84.4
Imazo+Anilofos 40+300 2.38 5.34 2.05 5.81 88.0
Imazo+Pretila 30+600 2.94 5.61 2.94 5.05 88.9
Imazo+Pretila 30+500 2.47 4.91 2.05 4.97 86.9
Imazo+Pretila 40+500 1.05 4.69 1.69 4.75 93.8
Anilofos 400 2.76 4.90 2.73 5.07 87.5
Pretilachlor 750 2.63 4.96 2.86 5.09 88.5
Weed Free 0.00 0.00 0.00 0.00 100
Weedy 4.44 6.49 4.31 6.60 0.00
C.D. at 5% 0.26 0.47 0.29 0.38
Table 2. Effect of tank mix herbicide on weed control index (WCI), weed density (No. m-2)and
total dry matter (gm-2) at different stage of crop growth.

Treatments Dose (g ha-1) E. crus-galli E. colona Caesaulia axillaris Cyperus spp.
Density D. M. Density D. M. Density D. M. Density
Imazosulfuron 30 1.79 4.85 1.79 5.19 1.19 1.14 1.79
Imazosulfuron 40 1.99 4.90 2.19 4.91 1.19 0.67 1.19
Imazosulfuron 50 1.79 4.87 1.99 5.15 0.59 1.18 1.19
Imazosulfuron 60 1.79 4.83 1.79 4.96 0.59 0.64 1.79
Imazo+Anilofos 40+250 1.19 3.22 1.19 3.37 1.19 1.10 0.59
Imazo+Anilofos 30+300 1.19 3.26 1.19 3.43 0.59 0.56 1.19
Imazo+Anilofos 40+300 0.59 1.65 0.59 1.59 0.00 0.00 0.00
Imazo+Pretila 30+600 1.19 3.30 1.19 3.31 0.59 0.53 1.19
Imazo+Pretila 30+500 1.19 3.27 0.00 0.00 0.00 0.00 0.00
Imazo+Pretila 40+500 1.19 3.22 0.00 0.00 0.00 0.00 0.00
Anilofos 400 1.19 3.33 1.19 3.37 1.19 1.19 1.19
Pretilachlor 750 1.19 3.36 1.19 3.39 1.79 1.60 0.59
Weed Free 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Weedy 2.95 5.76 2.73 6.18 2.19 2.33 2.52
C.D. at 5% 0.40 1.00 0.58 1.50 1.32 1.29 1.20
Table 3. Effect of tank mix herbicide on weed density (No.m-2)and total dry matter (gm-2) at
harvest stage of rice.

Treatments Dose (g ha-1) 30 DAT 60 DAT At harvest
Plant
height
(cm)
Dry
weight
(gm-2)
Plant
height (cm)
Dry weight
(gm-2)
Plant
height (cm)
Dry weight
(gm-2)
Imazosulfuron 30 48.5 99.1 84.0 446.3 108.0 881.7
Imazosulfuron 40 48.5 112.9 88.7 467.2 109.6 919.6
Imazosulfuron 50 48.1 113.6 88.9 470.0 111.0 990.8
Imazosulfuron 60 48.9 111.9 89.3 469.6 115.3 932.3
Imazo+Anilofos 40+250 50.5 116.4 89.5 478.3 116.3 990.3
Imazo+Anilofos 30+300 50.9 118.0 92.3 480.3 117.0 995.5
Imazo+Anilofos 40+300 51.6 120.0 95.1 504.3 118.0 998.3
Imazo+Pretila 30+600 52.7 120.0 94.5 499.4 119.6 1035.5
Imazo+Pretila 30+500 53.0 121.0 96.4 527.1 119.3 1065.4
Imazo+Pretila 40+500 53.5 121.2 96.4 542.4 119.8 1092.5
Anilofos 400 49.0 105.2 92.8 533.9 115.0 1139.9
Pretilachlor 750 50.0 116.9 87.7 462.4 113.3 1027.4
Weed Free 52.2 125.0 97.6 540.0 119.0 1183.7
Weedy 47.4 84.7 81.2 453.6 103.0 846.4
C.D. at 5% NS NS 7.2 72.2 5.1 82.1
Table 4. Effect of tank mix herbicides on growth parameter at different stage of rice crop.

Treatments
Dose (g ha-1)
Panicle
(No.m-2)
No. of grains
Penicle-1
1000 grain
w.t. (g)
Grain yield
(kg/ha)
Imazosulfuron 30 140 183 27.0 5104
Imazosulfuron 40 144 185 27.4 5260
Imazosulfuron 50 150 188 27.6 5312
Imazosulfuron 60 159 193 27.7 5580
Imazo+Anilofos 40+250 162 201 28.6 6094
Imazo+Anilofos 30+300 166 194 28.4 6146
Imazo+Anilofos 40+300 160 195 28.6 6250
Imazo+Pretila 30+600 165 189 28.9 5989
Imazo+Pretila 30+500 181 195 28.9 6146
Imazo+Pretila 40+500 188 205 29.1 6406
Anilofos 400 163 200 29.0 6198
Pretilachlor 750 170 198 28.9 5938
Weed Free 182 198 28.9 5833
Weedy 130 185 27.6 3906
C.D. at 5% 17.8 18.2 0.6 680
Table 5. Effect of tank mix herbicide on yield attributing characters, grain yield and crop weed
competition index (WI) of rice.

Treatments and dose (g/ha) Weed density/m2
grasses B L W Sedges Total
2012 2013 2012 2013 2012 2013 2012 2013
Bispyribac (25) 2.8 2.8 6.9 6.2 2.0 2.3 7.7 7.1
Pretilachlor (1000) 1.7 1.9 9.1 8.5 2.5 2.9 9.5 9.1
Penoxsulam (22.5) 2.5 2.7 6.1 6.0 1.7 1.8 6.7 6.7
Pyrazosulfuron (20) 2.3 2.6 8.9 9.4 0.7 0.7 9.2 9.7
Bispyribac+ethoxysulfuron 25+18.75) 1.3 1.7 4.1 4.7 1.6 1.7 4.5 5.2
Bispyribac+metsulfuron methyl +
chlorimuron-ethyl (20+4)
0.7 0.7 3.7 3.5 0.7 0.7 3.7 3.5
Pretilachlor fb ethoxy..( 750+18.75) 1.6 1.8 6.8 6.4 2.3 2.4 7.3 7.0
Pretilachlor fb metsulfuron methyl +
chlorimuron ethyl (750+4)
2.8 2.8 4.7 4.4 1.9 2.0 5.7 5.6
Pyrazosulfuron fbmanual weeding 20 0.7 0.7 6.8 6.9 0.7 0.7 6.8 6.9
Pretilachlor+bensulfuron (750+660) 0.7 0.7 5.9 5.5 2.0 2.3 6.1 5.9
Weed free 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7
Weedy check 11.2 11.1 14.3 14.7 7.2 8.5 19.5 2.3
LSD (P=0.05) 0.6 0.5 0.8 0.9 0.4 0.4 0.8 0.9
Table 6. Effect of treatment on weed density at 60 DAT
Source - Hossain and Mandal (W.B.), 2014

Treatments and dose (g/ha) Weed biomass (g/m2)
Grasses B-L weeds Sedges Total
2012 2013 2012 2013 2012 2013 2012 2013
Bispyribac (25) 1.5 1.5 3.0 2.9 1.6 1.6 3.5 3.5
Pretilachlor (1000) 1.4 1.5 3.1 3.4 1.4 1.5 3.5 3.8
Penoxsulam (22.5) 1.3 1.3 2.8 2.7 1.2 1.2 3.1 3.0
Pyrazosulfuron (20) 1.1 1.1 3.6 3.9 0.7 0.7 3.7 4.0
Bispyribac+ethoxysulfuron 25+18.75) 1.0 1.0 1.6 2.0 1.6 1.5 2.2 2.5
0.7 0.7 1.4 1.5 0.7 0.7 1.4 1.5
Pretilachlor fb ethoxy..( 750+18.75) 1.2 1.2 2.6 2.8 1.8 1.8 3.3 3.4
1.9 2.2 1.5 1.5 1.2 1.4 2.6 2.8
Pyrazosulfuron fbmanual weeding 20 0.7 0.7 2.4 2.5 0.7 0.7 2.4 2.5
Weed free 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7
Weedy check 3.9 4.6 9.3 9.9 2.8 3.5 10.5 11.4
LSD (P=0.05) 0.4 0.3 0.4 0.5 0.3 0.3 0.4 0.6
Table 7. Effects of treatments on weed biomass at 60 DAT

Treatments and dose (g/ha) Plant ht.(cm) Plant population Biomass (g/m2)
Effective
till./m2
2012 2013 2012 2013 2012 2013 2012 2013
Bispyribac (25) 107 106 410 411 572 322 315.0 69.3
Pretilachlor (1000) 102 104 397 399 581 305 296.7 65.0
Penoxsulam (22.5) 102 106 402 405 583 305 296.0 67.3
Pyrazosulfuron (20) 102 102 373 376 609 313 291.0 67.7
Bispyribac+ethoxysulfuron 20+18.75) 102 103 455 451 672 350 353.3 78.7
98 103 450 448 715 364 362.7 84.0
Pretilachlor fb ethoxy.. (750+18.75) 103 105 407 400 665 318 298.3 73.3
98 99 442 439 635 347 346.7 75.7
Pyrazosulfuron fbmanual weeding 20 106 105 437 431 670 347 336.7 72.7
Pretilachlor+bensulfuron (750+660) 99 101 433 429 605 338 329.3 73.3
Weed free 104 104 447 437 729 360 353.3 82.3
Weedy check 102 99 372 363 504 248 242.3 56.7
LSD (P=0.05) 6.8 3.5 35.1 53.6 96.9 76.7 32.2 48.4
Table 8. Effects of treatments on crop growth at 60 DAT in rice.

Treatments and dose (g/ha)
No. of
grains/panicle
Grain yield
(t/ha)
Cost of
cultn.(×
103/ha)
Gross
returns
(×103/ha)
Net
returns
(×103/h
a)
B:C
ratio
2012 2013 2012 2013
Bispyribac (25) 69.3 72.7 4.62 4.45 26.80 59.41 32.61 2.22
Pretilachlor (1000) 65.0 69.0 4.39 4.16 25.10 56.01 30.91 2.23
Penoxsulam (22.5) 67.3 61.3 4.38 4.15 25.90 55.85 29.95 2.16
Pyrazosulfuron (20) 67.7 61.7 4.50 4.31 24.90 57.73 32.83 2.32
Bispyribac+ethoxysulfuron (20+18.75) 78.7 75.0 5.03 4.83 27.50 64.55 37.05 2.35
chlorimuron-ethyl (20+4) 84.0 83.7 5.23 5.12 26.70 67.73 41.04 2.54
Pretilachlor fb ethoxysulfuron (750+18.75) 73.3 68.7 4.57 4.37 26.00 58.57 32.57 2.25
75.7 74.3 5.06 4.81 25.70 64.65 38.95 2.52
Pyrazosulfuron fb manual weeding (20) 72.7 69.0 4.96 4.76 26.90 63.68 36.78 2.37
Weed free 82.3 79.3 5.17 4.80 29.20 65.27 36.07 2.24
Weedy check 56.7 58.3 3.57 3.27 23.60 44.74 21.14 1.90
LSD (P=0.05) 7.6 13.5 0.46 0.81 - 6.43 6.43 0.25
Table 9. Effects of different weed control treatments on yield and economics.

Treatments
Dose
(g/ha)
Weed density (no./m2) Weed dry matter (g/m2)
WCE
%
Grain
yield
(t/ha)Grasses BLW Sedges Grasses BLW Sedges
Bispyribac 25 3.1 5.6 1.0 3.8 2.4 1.0 77.7 6.0
Pretilachlor 1000 3.6 8.1 1.9 4.9 3.6 1.7 55.3 5.83
Penoxsulam 22.5 2.8 5.8 2.5 4.6 2.5 2.1 65.9 6.02
Pyrazosulfuron 20 4.1 8.1 2.6 6.0 3.4 2.5 46.0 5.55
Bispyribac+ethoxysulfuron 25+18.75 1.5 3.0 1.0 1.2 1.4 1.0 98.2 6.51
chlorimuron-ethyl
20+4 1.9 4.7 2.1 2..0 1.9 1.5 91.6 6.38
Pretilachlor fb ethoxysulfuron 700/18.75 2.2 5.3 1.0 3.1 1.9 1.0 86.6 6.22
chlorimuron ethyl
700/4 1.5 4.5 1.9 1.6 1.9 1.5 93.4 6.39
Pyrazosulfuron fb manual weeding 20/25 2.5 6.2 1.0 4.1 2.3 1.0 76.0 6.05
Pretilachlor+bensulfuron 750+660 3.2 6.9 3.1 4.6 2.7 3.3 56.3 5.96
Weed free - 1.0 1..0 1.0 1..0 1.0 1.0 100 6.74
Weedy check - 5.4 10.6 5.2 6.7 1.3 4.9 0 4.38
LSD (P=0.05) - 0.5 0.4 0.2 0.6 0.3 0.3 - 0.59
Table 10. Effect of treatments on total weed density, weed dry weight, weed control efficiency
and grain yield in transplanted rice.
Source - Kabdal et al. 2014 (G.B.P.U.A&T. UTTARAKHAND)

Treatments (g/ha-1) Weed density (No. m-2) at 60 DAT
Grasses Sedges Broad leaved
2006 2007 2006 2007 2006 2007
Butachlor@ 1.5 kg 2.32 1.90 2.82 2.73 5.05 5.30
Bensulfuron methyl@ 50 g 2.62 2.23 1.65 1.65 4.17 3.57
Bensulfuron methyl@ 60 g 2.49 2.06 1.48 1.24 3.49 3.17
Chlorimuron ethyl + metsulfuron methyl @4 g 4.10 2.06 1.90 2.06 1.90 1.90
Butachlor 1.5 kg fb bensulfuronmethyl @ 50 g 1.65 1.90 1.24 1.48 3.25 2.49
Butachlor 1.5 kg fb bensulfuron-methyl @ 60 g 1.48 1.52 1.48 1.24 2.82 2.34
Butachlor 1.5 kg fb chlorimuron ethyl + metsulfuron
methyl@4g
1.79 1.48 2.62 2.20 1.24 1.73
Flufenacet@90 g 1.82 2.06 2.62 2.20 3.08 2.06
Butachlor @ 1.5 kg fb hand weeding 20 DAT 1.65 1.52 1.90 1.79 2.06 2.94
Hand weeding (20 and 40 DAT) 2.37 2.06 3.17 2.98 2.94 4.10
Weed free 1.00 1.00 1.00 1.00 1.00 1.00
Weedy check 6.60 4.71 4.49 3.94 6.34 5.82
CD at 5% 0.92 0.49 0.79 0.74 0.84 0.87
Source - Bhat et al. 2011(S.K.U.A.&T. Kashmir)
Table 11. Density of weed categories as influenced by weed control measures.

Treatments and dose (g/ha)
Panicles m-2 Grains panicle-1 Grain yield (q ha-1)
2006 2007 2006 2007 Pooled
Butachlor@ 1.5 kg 454.0 462.0 88.6 92.0 66.81
Bensulfuron methyl@ 50 g 470.6 475.3 86.6 89.3 69.27
Bensulfuron methyl@ 60 g 435.3 456.6 86.0 83.0 67.18
Chlorimuron ethyl + metsulfuron methyl @4 g 484.6 499.3 100.6 82.0 66.28
Butachlor 1.5 kg fb bensulfuronmethyl @ 50 g 462.7 486.0 96.7 97.3 69.75
Butachlor 1.5 kg fb bensulfuron-methyl @ 60 g 496.0 462.6 102.0 91.4 69.70
Butachlor 1.5 kg fb chlorimuron ethyl + metsulfuron
methyl@4g
507.0 481.3 106.0 103.3 72.26
Flufenacet@90 g 500.0 472.0 83.3 102.7 70.43
Butachlor @ 1.5 kg fb hand weeding 20 DAT 471.30 492.0 81.3 100.7 70.19
Hand weeding (20 and 40 DAT) 461.30 452.6 82.6 84.7 66.37
Weed free 518.0 506.0 106.0 113.3 74.25
Weedy check 310.6 368.0 49.3 73.3 49.24
CD at 5% 32.7 51.3 12.5 11.07 7.96
Table 12.Yield and yield attributes of rice as influenced by different weed control treatments
Source - Bhat et al. 2011(S.K.U.A.&T. Kashmir)

Treatment
Dose
(kg/ha)
Time of
application (DAT)
D.M.(g/m
2) at 60
DAT
W.C.E. (%)
at 60 DAT
Panicle
/m2
Panicle
weight
(g)
Glyphosate 0.75 15 DBCE 16.97 36.03 332 2.70
Butachlor 1.5 5 DAT 19.43 26.76 347 2.59
Bensulfuron –methyl +
pretilachlor 0.06+0.6 5 DAT 13.2 50.25 361 2.95
Glyphosate+butachlor 0.75+1.5 15 DBCE 13.53 49.00 384 2.81
Glyphosate+bensulfuro
n-methyl+pretilachlor
0.75+0.06+
0.06
5 DAT 10.3 61.18 406 3.11
Hand weeded twice 20 & 40 DAT 11.97 54.88 354 2.73
Use of cono weeder 20 & 40 DAT 11.67 56.01 382 2.80
Non weeded control - - 26.53 288 2.35
LSD(P=0.05) 5.96 18.23 0.25
Source-Ramachandra et al. 2014 (Mandya, Karnataka)
Table 13. Weed biomass, weed control efficiency panicle per m2 and panicle weight (g) as
influenced by different weed management practices in transplanted rice.
DBCE-Days before crop establishment

Treatment
Dose (kg/ha)
Time of
application
(DAT)
Grain
yield
(t/ha)
Total
cost of
culti.(×
103/ha)
Gross
Returns
(×103/ha)
Net
returns
(×103/h
a)
B:C
Glyphosate 0.75 15 DBCE 5.99 32.65 85.93 53.28 1.63
Butachlor 1.5 5 DAT 6.29 33.64 89.73 56.08 1.60
Bensulfuron –methyl +
pretilachlor
0.06+0.6 5 DAT 6.73 34.60 96.33 61.72 1.78
Glyphosate+butachlor 0.75+1.5 15 DBCE 6.55 33.86 93.60 59.74 1.76
Glyphosate+bensulfuron-
methyl+pretilachlor
0.75+0.06+0.06 5 DAT 7.02 34.90 100.110 65.21 1.87
Hand weeded twice 20 & 40 DAT 6.52 35.60 93.17 57.57 1.67
Use of cono weeder 20 & 40 DAT 6.59 34.40 93.84 59.44 1.73
Non weeded control - - 4.50 32.50 63.66 31.16 0.95
LSD(P=0.05) 0.31
Source - Ramachandra et al. 2014 (Mandya, Karnataka)
Table 14. Effect of weed management practices on the yield and economics in transplanted rice.
DBCE-Days before crop establishment

Treatments dose (g/ha) Weed density (No./m2)
Grasses Sedges BLW
Pretilachlor (1000) 16.33 98.00 7.00
Oxadiargyl (175 ) 10.66 85.66 10.66
Pyrazosulfuron-ethyl (35) 18.00 50.33 12.33
Pretilachlor fb penoxsulam (1000+25) 5.33 48.33 6.00
Oxadiargyl fb penoxsulam (175+25) 2.33 30.66 5.00
Pyrazosulfuron-ethyl fb penoxsulam (35+25) 15.33 20.66 12.00
Pretilachlor fb bispyribac-sodium (1000+30 ) 1.33 32.66 5.66
Oxadiargyl fb bispyribac sodium (175+30) 0.66 26.00 5.00
Pyrazosulfuron-ethyl fb bispyribac-sodium (35+30 ) 7.00 18.33 11.66
Cyhalofop-butyl (125) 6.33 105.00 38.66
HW twice at 20 and 40 DAT 7.00 15.66 4.33
Unweeded check (control) 36.66 121.00 72.0
LSD(P=0.05) 0.71 0.17 0.31
Table 15. Effect of sequential application of pre and post emergence herbicide on weed
density in transplanted rice.
Source - Kiran and Subramanyam 2010 (S.V.A.C., Tirupati, A.P.)

Treatments and dose (g/ha) Weed dry wt. (g/m2)
Grasses Sedges BLW
Pretilachlor (1000) 28.32 45.67 4.21
Oxadiargyl (175) 22.68 31.27 6.95
Pyrazosulfuron-ethyl (35) 36.66 27.64 8.00
Pretilachlor fb penoxsulam (1000+25) 12.54 20.74 3.92
Oxadiargyl fb penoxsulam (175+25) 6.04 14.69 2.69
Pyrazosulfuron-ethyl fb penoxsulam (35+25) 32.48 10.98 7.82
Pretilachlor fb bispyribac-sodium (1000+30 ) 8.67 14.98 3.84
Oxadiargyl fb bispyribac sodium (75+30) 4.52 12.60 3.01
Pyrazosulfuron-ethyl fb bispyribac-sodium (35+30) g/ha 11.78 8.52 5.12
Cyhalofop-butyl (125) 12.52 46.84 25.12
HW twice at 20 and 40 DAT 8.00 7.97 2.78
Unweede check (control) 69.90 54.63 47.02
LSD(P=0.05) 0.38 0.16 0.18
Table 16. Effect of sequential application of pre and post emergence herbicide on weed dry
weight in transplanted rice

Treatments (dose g/ha) No. of filled
grains/panicle
1000-grain
wt.(g)
Pretilachlor (1000) 103.6 13.87
Oxadiargyl (175) 109.0 14.08
Pyrazosulfuron-ethyl (35) 105.3 14.22
Pretilachlor fb penoxsulam (1000+25) 114.0 14.33
Oxadiargyl fb penoxsulam (175+25) 116.6 14.82
Pyrazosulfuron-ethyl fb penoxsulam (35+25) 112.3 14.47
Pretilachlor fb bispyribac-sodium (1000+30) 115.6 14.70
Oxadiargyl fb bispyribac sodium (175+30) 118.6 14.96
Pyrazosulfuron-ethyl fb bispyribac-sodium (35+30) 115.0 14.62
Cyhalofop-butyl (125) 101.3 13.70
HW twice at 20 and 40 DAT 120.6 15.05
Unweede check (control) 99.6 13.42
LSD(P=0.05) 4.22 NS
Table 17. Effect of sequential application of pre and post emergence herbicide on no. of
filled grains/panicle and 1000 seed weight in transplanted rice

Treatments and dose (g/ha) Weed dry wt. (No./m2)
Grain yield
(kg/ha)
Straw
yield
(kg/ha)
B:C ratio
Pretilachlor (1000) 5325 6650 2.64
Oxadiargyl (175) 5553 6801 2.81
Pyrazosulfuron-ethyl (35) 5495 6768 2.74
Pretilachlor fb penoxsulam (1000+25) 5822 6928 2.63
Oxadiargyl fb penoxsulam (175+25) 6548 7324 3.00
Pyrazosulfuron-ethyl fb penoxsulam (35+25) 5698 6858 2.59
Pretilachlor fb bispyribac-sodium (1000+30) 6264 7064 2.71
Oxadiargyl fb bispyribac sodium (175+30) 6758 7442 3.06
Pyrazosulfuron-ethyl fb bispyribac-sodium (35+30) 5947 6837 2.67
Cyhalofop-butyl(125) 5126 6563 2.41
HW twice at 20 and 40 DAT 6812 7550 3.04
Unweede check (control) 4552 6362 2.39
LSD(P=0.05) 399 506 0.24
Table 18. Effect of sequential application of pre and post emergence herbicide on grain,
straw yield and B:C ratio in transplanted rice.

Conclusion
Pre-emergence application of pretilachlor + bensulfuron @ (1000+660) g/ha is effective
in controlling grassy weeds
 Post emergence application of bispyribac sodium + metsulfuron-methyl + chlorimuron
ethyl @ (20+4 g/ha) effectively controls grassy, broad leaves as well as sedge weed
population besides higher crop biomass, effective tiller, number of grain per panicle, grain
yield and higher B:C ratio and the same has been found to be better for low weed density
and weed dry matter also apart from higher weed control efficiency.

HERBICIDE COMBINATION FOR CONTROL OF COMPLEX WEED FLORA IN TRANSPLANTED RICE

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