Herbicide combination for control of complex

weed flora in transplanted rice

Presenter :- Jai PrakashId. No. 0812Ph. 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.

IndiaChina

Indonesia

Thila

nd

Bangladesh

VietnamBurm

a

Philippines

Combodia

Pakist

an

Others0

5

10

15

20

25

30

35

40

45

5043.94

30.58

13.83 12.37 11.777.9 7.5

4.74 3.1 2.7

26.73

area Mha

India27%

China19%

Indonesia8%

Thiland7%

Bangladesh7%

Vietnam5%

Burma5%

Philippines3%

Combodia2%

Pakistan2% Others

16%

Share %Country wise area and percent share in paddy crop

China India

Indonesia

Bangladesh

Vietnam

Thail

andBurm

a

Philippines

BrazilJapan

Others0

50

100

150

200

250

205.2

159.2

71.2751.5 44.03 36.06 28.76

18.43 11.78 10.75

103.9Rice production M.T.

China 27%

India21%

Indonesia10%

Bangladesh7%

Vietnam7%

Thailand5%

Burma4%

Philippines

2%

Brazil2%

Japan1%

Others14%

Share % Country wise production (M.T.) and percent share of rice

World

Australi

aEg

upt

United St

ateTu

rkey

Uruguay

GreecePeru

Uzbekaist

an

Morocco

Tajik

istan

ChinaIndia

0

20

40

60

80

100

120

44.85

102.1795.29

86.2381.38 78.55 77.14 77.11 76.5 75.43 75.38

67.1

36.23

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 27602. Uttar Pradesh 5.86 14.42 24603. Andhra Pradesh 3.63 11.51 31734. Punjab 2.85 11.37 39985. Orissa 4.02 7.30 18146. Chhattisgarh 3.78 6.61 17467. Tamilnadu 1.49 4.05 27128. Bihar 3.30 7.53 22829. Assam 2.49 5.13 206110. Haryana 1.22 3.98 327211. Karnataka 1.28 3.36 263212. Maharashtra 1.56 3.06 196313. M.P. 1.88 2.77 147414. Jharkhand 1.41 3.16 223815. Gujarat 0.70 1.54 219816. Kerala 0.20 0.51 257717. 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 21.172002-03 5.21 9.59 18.402003-04 5.72 12.48 21.812004-05 5.34 10.75 18.112005-06 5.57 11.12 19.962006-07 5.82 10.88 18.692007-08 5.69 11.73 20.622008-09 6.01 13.05 21.712009-10 5.14 10.71 20.812010-11 5.63 11.94 21.202011-12 5.95 13.53 23.582012-13 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

HerbicideinsecticideFungicideOther

Consumption of different pesticides

Source - Yaduraju,2006

Herbicide use in crops - India

74%

7%

6%

4% 9%

CerealsNon selective fieldsPlantation cropSoyabeanOthers

Source - Yaduraju,2006

05/01/2023 1005/01/2023

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 zerotillage 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 weeds1. 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

Herbicide saves time

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 DATWeed density Dry matter Weed density Dry matter

Imazosulfuron 30 3.71 2.05 3.57 5.10Imazosulfuron 40 3.39 1.94 3.60 5.03Imazosulfuron 50 3.29 1.92 3.43 5.02Imazosulfuron 60 3.36 1.86 3.33 4.99Imazo+Anilofos 40+250 3.70 1.43 3.17 4.68Imazo+Anilofos 30+300 2.53 1.20 2.76 4.37Imazo+Anilofos 40+300 1.55 1.10 2.39 4.11Imazo+Pretilachlor 30+600 2.63 1.18 3.08 3.99Imazo+Pretilachlor 30+500 2.39 0.90 2.28 4.20Imazo+Pretilachlor 40+500 1.05 0.82 1.55 3.42Anilofos 400 2.18 0.87 2.81 3.45Pretilachlor 750 2.63 1.07 2.68 4.07Weed Free 0.00 0.00 0.00 0.00Weedy 4.38 2.27 4.50 6.22C.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 WCIImazosulfuron 30 3.55 6.27 3.28 6.37 71.1Imazosulfuron 40 3.55 6.07 3.46 6.28 69.7Imazosulfuron 50 3.49 5.85 3.33 5.94 67.8Imazosulfuron 60 3.27 5.71 3.13 5.84 69.8Imazo+Anilofos 40+250 3.32 6.10 2.78 5.94 78.3Imazo+Anilofos 30+300 2.76 5.64 2.70 5.60 84.4Imazo+Anilofos 40+300 2.38 5.34 2.05 5.81 88.0Imazo+Pretila 30+600 2.94 5.61 2.94 5.05 88.9Imazo+Pretila 30+500 2.47 4.91 2.05 4.97 86.9Imazo+Pretila 40+500 1.05 4.69 1.69 4.75 93.8Anilofos 400 2.76 4.90 2.73 5.07 87.5Pretilachlor 750 2.63 4.96 2.86 5.09 88.5Weed Free 0.00 0.00 0.00 0.00 100Weedy 4.44 6.49 4.31 6.60 0.00C.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.

Source – Manhas et al. 2012 (Uttarakhand)

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 1.79Imazosulfuron 40 1.99 4.90 2.19 4.91 1.19 0.67 1.19Imazosulfuron 50 1.79 4.87 1.99 5.15 0.59 1.18 1.19Imazosulfuron 60 1.79 4.83 1.79 4.96 0.59 0.64 1.79Imazo+Anilofos 40+250 1.19 3.22 1.19 3.37 1.19 1.10 0.59Imazo+Anilofos 30+300 1.19 3.26 1.19 3.43 0.59 0.56 1.19Imazo+Anilofos 40+300 0.59 1.65 0.59 1.59 0.00 0.00 0.00Imazo+Pretila 30+600 1.19 3.30 1.19 3.31 0.59 0.53 1.19Imazo+Pretila 30+500 1.19 3.27 0.00 0.00 0.00 0.00 0.00Imazo+Pretila 40+500 1.19 3.22 0.00 0.00 0.00 0.00 0.00Anilofos 400 1.19 3.33 1.19 3.37 1.19 1.19 1.19Pretilachlor 750 1.19 3.36 1.19 3.39 1.79 1.60 0.59Weed Free 0.00 0.00 0.00 0.00 0.00 0.00 0.00Weedy 2.95 5.76 2.73 6.18 2.19 2.33 2.52C.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.

Source – Manhas et al. 2012 (Uttarakhand)

Treatments Dose (g ha-1) 30 DAT 60 DAT At harvestPlant

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 84.0 446.3 108.0 881.7Imazosulfuron 40 48.5 112.9 88.7 467.2 109.6 919.6Imazosulfuron 50 48.1 113.6 88.9 470.0 111.0 990.8Imazosulfuron 60 48.9 111.9 89.3 469.6 115.3 932.3Imazo+Anilofos 40+250 50.5 116.4 89.5 478.3 116.3 990.3Imazo+Anilofos 30+300 50.9 118.0 92.3 480.3 117.0 995.5Imazo+Anilofos 40+300 51.6 120.0 95.1 504.3 118.0 998.3Imazo+Pretila 30+600 52.7 120.0 94.5 499.4 119.6 1035.5Imazo+Pretila 30+500 53.0 121.0 96.4 527.1 119.3 1065.4Imazo+Pretila 40+500 53.5 121.2 96.4 542.4 119.8 1092.5Anilofos 400 49.0 105.2 92.8 533.9 115.0 1139.9Pretilachlor 750 50.0 116.9 87.7 462.4 113.3 1027.4Weed Free 52.2 125.0 97.6 540.0 119.0 1183.7Weedy 47.4 84.7 81.2 453.6 103.0 846.4C.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.

Source – Manhas et al. 2012 (Uttarakhand)

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 5312Imazosulfuron 60 159 193 27.7 5580Imazo+Anilofos 40+250 162 201 28.6 6094Imazo+Anilofos 30+300 166 194 28.4 6146Imazo+Anilofos 40+300 160 195 28.6 6250Imazo+Pretila 30+600 165 189 28.9 5989Imazo+Pretila 30+500 181 195 28.9 6146Imazo+Pretila 40+500 188 205 29.1 6406Anilofos 400 163 200 29.0 6198

Pretilachlor 750 170 198 28.9 5938Weed Free 182 198 28.9 5833Weedy 130 185 27.6 3906C.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.

Source – Manhas et al. 2012 (Uttarakhand)

Treatments and dose (g/ha) Weed density/m2

grasses B L W Sedges Total2012 2013 2012 2013 2012 2013 2012 2013

Bispyribac (25) 2.8 2.8 6.9 6.2 2.0 2.3 7.7 7.1Pretilachlor (1000) 1.7 1.9 9.1 8.5 2.5 2.9 9.5 9.1Penoxsulam (22.5) 2.5 2.7 6.1 6.0 1.7 1.8 6.7 6.7Pyrazosulfuron (20) 2.3 2.6 8.9 9.4 0.7 0.7 9.2 9.7Bispyribac+ethoxysulfuron 25+18.75) 1.3 1.7 4.1 4.7 1.6 1.7 4.5 5.2Bispyribac+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 7.0Pretilachlor 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 6.9Pretilachlor+bensulfuron (750+660) 0.7 0.7 5.9 5.5 2.0 2.3 6.1 5.9Weed free 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7Weedy check 11.2 11.1 14.3 14.7 7.2 8.5 19.5 2.3LSD (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 2013Bispyribac (25) 1.5 1.5 3.0 2.9 1.6 1.6 3.5 3.5Pretilachlor (1000) 1.4 1.5 3.1 3.4 1.4 1.5 3.5 3.8Penoxsulam (22.5) 1.3 1.3 2.8 2.7 1.2 1.2 3.1 3.0Pyrazosulfuron (20) 1.1 1.1 3.6 3.9 0.7 0.7 3.7 4.0Bispyribac+ethoxysulfuron 25+18.75) 1.0 1.0 1.6 2.0 1.6 1.5 2.2 2.5Bispyribac+metsulfuron methyl + chlorimuron-ethyl (20+4) 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 3.4Pretilachlor fb metsulfuron methyl + chlorimuron ethyl (750+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

Pretilachlor+bensulfuron (750+660) 0.7 0.7 2.2 2.5 2.0 2.2 2.9 3.2Weed free 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7Weedy check 3.9 4.6 9.3 9.9 2.8 3.5 10.5 11.4LSD (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

Source - Hossain and Mandal (W.B.), 2014

Treatments and dose (g/ha) Plant ht.(cm) Plant population Biomass (g/m2) Effective till./m2

2012 2013 2012 2013 2012 2013 2012 2013Bispyribac (25) 107 106 410 411 572 322 315.0 69.3Pretilachlor (1000) 102 104 397 399 581 305 296.7 65.0Penoxsulam (22.5) 102 106 402 405 583 305 296.0 67.3Pyrazosulfuron (20) 102 102 373 376 609 313 291.0 67.7Bispyribac+ethoxysulfuron 20+18.75) 102 103 455 451 672 350 353.3 78.7Bispyribac+metsulfuron methyl + chlorimuron-ethyl (20+4) 98 103 450 448 715 364 362.7 84.0

Pretilachlor fb ethoxy.. (750+18.75) 103 105 407 400 665 318 298.3 73.3Pretilachlor fb metsulfuron methyl + chlorimuron ethyl (750+4) 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 73.3Weed free 104 104 447 437 729 360 353.3 82.3Weedy check 102 99 372 363 504 248 242.3 56.7LSD (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.

Source - Hossain and Mandal (W.B.), 2014

Treatments and dose (g/ha) No. of

grains/panicleGrain 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 2.22Pretilachlor (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

Bispyribac+metsulfuron methyl + 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

Pretilachlor fb metsulfuron methyl + chlorimuron ethyl (750+4) 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

Pretilachlor+bensulfuron (750+660) 73.3 67.0 4.93 4.71 25.60 63.14 37.54 2.47Weed 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 1.90LSD (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.

Source - Hossain and Mandal (W.B.), 2014

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 6.0Pretilachlor 1000 3.6 8.1 1.9 4.9 3.6 1.7 55.3 5.83Penoxsulam 22.5 2.8 5.8 2.5 4.6 2.5 2.1 65.9 6.02Pyrazosulfuron 20 4.1 8.1 2.6 6.0 3.4 2.5 46.0 5.55Bispyribac+ethoxysulfuron 25+18.75 1.5 3.0 1.0 1.2 1.4 1.0 98.2 6.51

Bispyribac+metsulfuron methyl + 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 6.22Pretilachlor fb metsulfuron methyl + 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 6.05Pretilachlor+bensulfuron 750+660 3.2 6.9 3.1 4.6 2.7 3.3 56.3 5.96Weed 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 4.38LSD (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 3.17Chlorimuron 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 2.06Butachlor @ 1.5 kg fb hand weeding 20 DAT 1.65 1.52 1.90 1.79 2.06 2.94Hand weeding (20 and 40 DAT) 2.37 2.06 3.17 2.98 2.94 4.10Weed free 1.00 1.00 1.00 1.00 1.00 1.00Weedy check 6.60 4.71 4.49 3.94 6.34 5.82CD 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 67.18Chlorimuron 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 70.43Butachlor @ 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 66.37Weed free 518.0 506.0 106.0 113.3 74.25Weedy check 310.6 368.0 49.3 73.3 49.24CD 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)

TreatmentDose

(kg/ha)Time of

application (DAT)D.M.(g/m2) at 60

DATW.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+bensulfuron-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 0.95LSD(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 7.00Oxadiargyl (175 ) 10.66 85.66 10.66Pyrazosulfuron-ethyl (35) 18.00 50.33 12.33Pretilachlor fb penoxsulam (1000+25) 5.33 48.33 6.00Oxadiargyl fb penoxsulam (175+25) 2.33 30.66 5.00Pyrazosulfuron-ethyl fb penoxsulam (35+25) 15.33 20.66 12.00Pretilachlor fb bispyribac-sodium (1000+30 ) 1.33 32.66 5.66Oxadiargyl fb bispyribac sodium (175+30) 0.66 26.00 5.00Pyrazosulfuron-ethyl fb bispyribac-sodium (35+30 ) 7.00 18.33 11.66Cyhalofop-butyl (125) 6.33 105.00 38.66HW twice at 20 and 40 DAT 7.00 15.66 4.33Unweeded check (control) 36.66 121.00 72.0LSD(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 4.21Oxadiargyl (175) 22.68 31.27 6.95Pyrazosulfuron-ethyl (35) 36.66 27.64 8.00Pretilachlor fb penoxsulam (1000+25) 12.54 20.74 3.92Oxadiargyl fb penoxsulam (175+25) 6.04 14.69 2.69Pyrazosulfuron-ethyl fb penoxsulam (35+25) 32.48 10.98 7.82Pretilachlor fb bispyribac-sodium (1000+30 ) 8.67 14.98 3.84Oxadiargyl fb bispyribac sodium (75+30) 4.52 12.60 3.01Pyrazosulfuron-ethyl fb bispyribac-sodium (35+30) g/ha 11.78 8.52 5.12Cyhalofop-butyl (125) 12.52 46.84 25.12HW twice at 20 and 40 DAT 8.00 7.97 2.78Unweede check (control) 69.90 54.63 47.02LSD(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

Source - Kiran and Subramanyam 2010 (S.V.A.C., Tirupati, A.P.)

Treatments (dose g/ha) No. of filled grains/panicle

1000-grain wt.(g)

Pretilachlor (1000) 103.6 13.87Oxadiargyl (175) 109.0 14.08Pyrazosulfuron-ethyl (35) 105.3 14.22Pretilachlor fb penoxsulam (1000+25) 114.0 14.33Oxadiargyl fb penoxsulam (175+25) 116.6 14.82Pyrazosulfuron-ethyl fb penoxsulam (35+25) 112.3 14.47Pretilachlor fb bispyribac-sodium (1000+30) 115.6 14.70Oxadiargyl fb bispyribac sodium (175+30) 118.6 14.96Pyrazosulfuron-ethyl fb bispyribac-sodium (35+30) 115.0 14.62Cyhalofop-butyl (125) 101.3 13.70HW twice at 20 and 40 DAT 120.6 15.05Unweede check (control) 99.6 13.42LSD(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

Source - Kiran and Subramanyam 2010 (S.V.A.C., Tirupati, A.P.)

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 2.64Oxadiargyl (175) 5553 6801 2.81Pyrazosulfuron-ethyl (35) 5495 6768 2.74Pretilachlor fb penoxsulam (1000+25) 5822 6928 2.63Oxadiargyl fb penoxsulam (175+25) 6548 7324 3.00Pyrazosulfuron-ethyl fb penoxsulam (35+25) 5698 6858 2.59Pretilachlor fb bispyribac-sodium (1000+30) 6264 7064 2.71Oxadiargyl fb bispyribac sodium (175+30) 6758 7442 3.06Pyrazosulfuron-ethyl fb bispyribac-sodium (35+30) 5947 6837 2.67Cyhalofop-butyl(125) 5126 6563 2.41HW twice at 20 and 40 DAT 6812 7550 3.04Unweede check (control) 4552 6362 2.39LSD(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.

Source - Kiran and Subramanyam 2010 (S.V.A.C., Tirupati, A.P.)

ConclusionPre-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.

Thank You

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