my seminar on Use of Herbicides in Sequence for Control of Weeds in Maize by

2. Seminar
On
Use of Herbicides in Sequence for
Control of Weeds in Maize
UMESHA, C
PAL(S)2013
Sr. M.Sc.(Agri.)

3. Sequence of presentation
 Introduction
 Meaning and Principle for sequential application
 Importance of sequential application of herbicides
 Effect of Sequential application of herbicides
 Conclusion
 Future line of work

4. INTRODUCTION

5.  Maize (Zea mays L.) or Indian corn is one of the most important
cereals of the world. Apart from direct human consumption, maize
grains form an important ingredient of poultry and cattle feed.
 In India, maize is grown over an area of 8.33 million ha with an
annual production of 16.68 million tonnes and an average
productivity of 2002 kg ha-1.
 In Karnataka, maize occupies an area of 1.07 million ha with an
annual production of about 3.03 million tonnes and an average
productivity of 2833 kg ha-1

6. Maize has 3 major unique characteristics
 Its most obviously, maize looks different to the small grain cereals
like wheat, barley and rice.
 Commercial varieties of maize in more technologically advanced
farming systems are actually ‘hybrids’.
 Maize is physiologically different to many other crops having
system of photosynthesis which is called C4, this means that it
uses less water for a given level of yield

7.  Among all weed control methods cultural and mechanical are
tedious and time consuming besides labour intensive and costly. These
operations are difficult to carryout in the field.
 Use of pre and post-emergent herbicides would make the
herbicidal weed control more acceptable to farmers, which will not
change the existing agronomic practices but will allow for complete
control of weeds.

8.  Due to continous use of preemergent herbicides in crops and
cropping system, the emergence pattern of weeds has changed.
 This has resulted in development of post emergent herbicides. But
the efforts made to evaluate the efficacy pre and postemergent
herbicides applied in sequence lacking in maize.

9.  Among all the pests(insects, animals, diseases and weeds) in
India, weeds alone are responsible for about 25% loss of crop
production.
 weeds have been recognized as potential pests, its removed by
culturally, mechanically and chemically.
 Weeds reduce crop yield by 31.5%
22.7 % in winter
36.5% in summer, kharif seasons

10. Impact of weeds on different crop ecosystems
 It is estimated that loss of agriculture production
most developed countries- 5%
less developed countries- 10%
least developed countries- 25%
 It is estimated that yield loss by
weeds - 45%
Insects - 30%
Diseases - 20%
other pests - 5%
 The world food loss due to weeds was 287 mt of 11.5% of total
food production.

11. Weed flora
Crop weed competition
Critical CWC

12. Weeds Common name Local name Family
A. Grassy weeds
Cynodon dactylon Pers. Bermuda grass Garike, doob grass Poaceae
Digitaria marginata Crabgrass - Poaceae
Dinebra retroflexa - Poaceae
Echinochloa colonum Watergrass Jangli dan Poaceae
Eleusine indica L Goosegrass - Poaceae
Panicum spp. Panicum Barnyard grass Poaceae
Setaria italica Banara, bani Poaceae
B. Sedges
Cyperus rotundus L. Nut sedge Jeku, Motha purple Cyperaceae
Weed flora in maize

13. Contd…..
C. Broad leaved weeds
Ageratum conyzoides L Bill goat weed Mahkua Asteraceae
Amaranthus viriids L Pigweed Jungli chauli Amaranthaceae
Alternanthera sessilis L. - - Amaranthaceae
Argemona mexicana L. Mexican poppy Barghar, satyanasi Papavaraceae
Commelina benghalensis L. Dayflower, spider wort
Tropical
Insansia. Egali Commelinaceae
Cynotis cuculata Baghmula ,jigali Commelinaceae
Corchorus trilocularis Tiliaceae
Digera arvensis L. Lahasua Amaranthaceae
Euphorbia hirta L. Garden spurge Bari dudhi Euphorbiaceae
Euphorbia prostrate - Euphorbiaceae
Euphorbia geniculata Chotti dudhi Euphorbiaceae
Phyllanthus niruri L. Niruri Hezar dena Euphorbiaceae
Portulaca oleracea L. Purslane Kulfa Portulacaceae
Parthenium hysterophorus L. Carrot weed Congress Asteraceae
Physalis minima L. Ground cherry Ban makaya Solanaceae
Tridax procumbens L. Tridax phulani Asteracea

14. Sl.
No
Herbicides Recommended
dose
(kg a.i/ha)
Time of
application
Method of
application
Type of weed
control
1 Atrazine 1-1.5 PRE (0-3DAS) Soil applied Control annual
weeds
2 Simazine 1-1.5 PRE (0-3DAS) Soil applied Controls annual
weeds
3 Pendimethalin 0.75-1 PRE Soil applied Late emerging
annual weeds
commelina sp
4 2,4-D 1.0 POST
(3-4WAS)
Foliage
applied
Control Broad
leaved weeds
Different herbicides used in maize

15. 5 Alachlor 1.2-2.0 PRE
(0-3DAS)
Soil applied Control most of the
annual grasses and
broad leaved weeds
6 Paraquat
(Directed spray)
1.00 POST Foliage
applied
Control all weeds
7 Glyphosate
(Directed spray)
0.1 POST Foliage All type of weed
control
8 Butachlor 1.00 PRE Soil applied Control annual
weeds and BLW
Contd…..

16.  Preplant Soil incorporation of EPTC at 3-4 Kg/ha, mixed with
about 0.5kg/ha of either Atrazine or simazine is a very effective
treatment will also control sedges.
 Atrazine and simazine were first highly successful pre emergence
Herbicides in maize which replaced the earlier used herbicides 2,4-
D and MCPA in1960.
 Maize shows high tolerance to triazine group upto 5-6kg/ha in
commonly 1-2 kg/ha can be used to avoid phytotoxic residue
hazards of these herbicides.

17.  In dry areas atraziine and simazine should be slightly in corporated
into soil to improve herbicide efficacy.
 Alachlor and butachlor are most effective pre emergence
herbicides against the annual grasses than simazine and atrazine but
they weak against the broadleafs therefore judicious combination
of two groups of herbicides should control both types of weeds
effectively.
 Linuron is reported effective also against c.dactylon,
Pendimethalin(1kg/ha) has been newly added to the list of pre
emergence herbicides in maize.

18.  For early post emergence control of young weeds in maize a
very good herbicde combination is 0.5 kg alachlor +0.25 kg
atrazine +5% phytobland oil emulsion spray.
 Combination of propalachlor and linuron is preferred over
alachlor and metalachlor. Later at 3-6 leaf of weeds cyanazine
(0.75kg/ha)can be used on even still older weeds .

19. Merits and demerits of PRE emergence herbicides
Merits:
 Can be applied while planting /sowing
 With adequate rain, provides control through first 4 weeks
 Reduces late emerging weeds impact in maize
 Low annual grass populations
 Low to moderate population of annual BLW, Amaranths viridis.
Demerits:
 Dependence on adequate rain within narrow period of time
 Not effective on difficult BLW, perennial and high grass populations
 Moderate to high grass populations
 Biennial and perennial weeds.

20. Merits and demerits of POST emergence herbicides
Merits
 Controls late emerging weeds.
 Consistent control of low to moderate annual weed populations
Demerits
 Narrow window application, care should be taken applied at
particular stage.
 Moderate to high populations of grasses

21. It is application of herbicide one after the other i.e. pre-
plant followed by pre emergence/Pre emergence followed by
Post emergence application.
Ex: Application of Atrazine as Pre-emergence followed by 2,4-D as
Postemergence.
Meaning of sequential application of herbicides

22. Importance of Sequential application
 Provides enough weed control to prevent major weed
problems in maize.
 More consistent weed control of late emerging weeds
 Greater control and biomass reductions allow greater
maize yield
 More consistent weed control in SEQ than PRE or
Post alone

23. Principles
 To control broad spectrum / late emerging weeds
 To control weed flora throughout the growing season
 Difficulty in inter-culture operations due to unfavorable weather
 Pre emergence alone and Post emergence alone are
not much effective.

24. Research studies

25. Treatments Cyperus
esculentus
Convolvulu
s arvensis
Chenopodium
album
Amarantus
spp
Foramsulfuron 26.94 71.47 91.20 100
Nicosulfuron 55.63 74.42 100 93.80
Atrazin+lasso 27.92 36.70 84.88 56.01
Weedy 0 0 0 0
Table-1- Weed control (percent) with herbicides
NURAKY et al, 2011

26. Treatments Cyperus
esculentus
Convolvulu
s arvensis
Chenopodium
album
Amarantus
spp
Foramsulfuron 1.56 1.28 0 0
Nicosulfuron 1.25 0 0 0
Atrazin+lasso 3 1.41 0 0
Weedy 9.48 2.31 9.25 6.91
Table 2- weed density (number) at 26 days after sowing
NURAKY et al, 2011

27. Treatment
Plant height at
maturity (cm)
Ear height
aboveground (cm)
Leaf area index
No. of
leaves/plant (at
maturity)
Atrazine
Trazine
Callitraz
125.0
130.2
49.0
46.8
1.160
1.123
13.5
12.2
2,4-D
Calliherbe
Bextra
121.8
135.7 0
47.8
51.4
0.980
1.41
12.1
13.1
Glyphosate
Kalach 360L
Fire
Weed Out
120.1
143.6
128.5
66.3
56.7
48.5
1.110
1.490
1.343
12.7
13.4
13.7
Paraquat
Benaxone
Gramoxone Super
140.5
126.1
59.9
48.6
1.07
1.0133
13.1
12.8
Control (No herbicide)
LSD (P = 0.05)
126. 6
NS
44.8
NS
0.935
NS
13.2
NS
Table 3. Maize plant heights, height of ear above ground, leaf area
index number of leaves per plant measured at 10 WAP.
Ghana. Larbi,2013

28. Treatments
Weed index
(%)
WCE (%) Grain yield
(kg/ha)
1.Atrazine 1.25 kg/ha +1 IC at 30DAS 24.75 75.37 5297
2.Atrazine 1.25 kg/ha fb Atrazine 0.50 kg/ha 16.53 84.85 5876
3.Atrazine 1.25 kg/ha fb Atrazine 1.00 kg/ha 10.86 88.32 6275
4.Butachlor 1.00kg/ha + 1 IC at 30DAS 30.42 74.47 4898
5.Butachlor 1.00kg/ha fb Atrazine 0.50 kg/ha 17.37 83.40 5817
6.Butachlor 1.00kg/ha fb Atrazine 0.50 kg/ha 14.84 85.18 6020
7.Atrazine 1.25 kg/ha fb 2,4-D 0.5 kg/ha 8.52 91.58 6440
8.Butachlor 1.00kg/ha fb 2,4-D 0.5 kg/ha 10.22 89.72 6320
9.Farmers practice (1 IC at 20 and at 1 HW30 DAS) 20.69 76.75 5583
10.Weed free check 0.00 94.67 7040
11.Weedy check 40.4 0.00 4195
SEm± 3.80 2.84 285
CD(0.05) 11.27 8.40 841
Table 4: WCE, WI and grain yield at different growth stages as influenced by
sequential application
ARS, Devihosur Mallikarjun, 2008

29. Treatments
Plant height
(cm)
LAI Net
returns
(Rs ha-1)
B: C
ratio
T1: Atrazine 1.25 kg/ha +1 IC at 30DAS 180.52 1.82 19602 2.27
T2: Atrazine 1.25 kg/ha fb Atrazine 0.50 kg/ha 185.55 2.21 22991 2.45
T3: Atrazine 1.25 kg/ha fb Atrazine 1.00 kg/ha 190.76 2.37 25130 2.55
T4: Butachlor 1.00kg/ha + 1 IC at 30DAS 179. 16 1.75 17526 2.17
T5: Butachlor 1.00kg/ha fb Atrazine 0.50 kg/ha 182.78 2.07 23005 2.48
T6: Butachlor 1.00kg/ha fb Atrazine 0.50 kg/ha 186.34 2.29 23962 2.52
T7: Atrazine 1.25 kg/ha fb 2,4-D 0.5 kg/ha 193.38 2.54 26601 2.67
T8: Butachlor 1.00kg/ha fb 2,4-D 0.5 kg/ha 191.48 2.46 26224 2.70
T9: Farmers practice (1 IC at 20 and at 1 HW30
DAS)
181.76 1.96 21082 2.33
T10: Weed free check 196.46 2.69 27821 2.50
T11: Weedy check 173.32 1.70 14046 2.01
CD at 5% 8.68 0.41 3903 0.26
Mallikarjun, 2008ARS, Devihosur
Table 5 : Effect of weed control treatments on growth parameters and economics as
influenced by sequential application

30. Treatment
Weed count
(per 0.5 m2)
Weed dry
weight (per
0.5 m2)
Weed control
index (%)
TDMP at harvest
of maize (g/plant)
T1 : Atrazine 1.25 kg a.i./ha (PRE) fb. Atrazine
1.50 kg a.i./ha (POST)
4.43 3.87 75.9 292
T2 : Atrazine 1.25 kg a.i./ha (PRE) fb. Atrazine
1.75 kg a.i./ha (POST)
4.33 4.47 67.4 327
T3 : Atrazine 1.25 kg a.i./ha (PRE) fb. Paraquat
1.0 kg a.i./ha (POST)
3.93 3.10 84.8 304
T4 : Atrazine 1.25 kg a.i./ha (PRE) fb. Paraquat
1.5 kg a.i./ha (POST)
4.10 3.40 81.5 317
T5 : Atrazine 1.25 kg a.i./ha (PRE) fb. Glyphosate
2.5 kg a.i./ha (POST)
3.08 3.29 82.7 332
T6 : Atrazine 1.25 kg a.i./ha (PRE) fb. Glyphosate
3.0 kg a.i./ha (POST)
3.43 3.36 82.0 284
T7 : Atrazine 1.25 kg a.i./ha (PRE) fb. 2,4-D Na
salt 2.0 kg a.i./ha (POST)
4.10 3.84 76.2 277
T8 : Atrazine 1.25 kg a.i./ha (PRE) fb. 2,4-D Na
salt 3.0 kg a.i./ha (POST)
3.89 3.91 75.3 292
T9 : Atrazine 1.25 kg a.i./ha (PRE) fb. (2 IC @ 30
and 45 DAS) + 1 HW (between 30 and 45
DAS)
3.29 3.70 77.5 310
T10 : Weedy check 6.23 7.78 0 298
SEm+ 0.2 0.0 0.53 3.26
CD at 5% 0.6 0.1 1.56 9.68
Ishrat, 2010
Table 6 : Weed dynamics as influenced by pre and post emergence application of
herbicides in maize
Ramdurg

31. Treatment
100-seed
weight (g)
Grain yield
(kg/ha)
Net income
(Rs./ha)
B:C
T1 : Atrazine 1.25 kg a.i./ha (PRE) fb. Atrazine 1.50
kg a.i./ha (POST)
36.5 4637 51802 3.48
T2 : Atrazine 1.25 kg a.i./ha (PRE) fb. Atrazine 1.75
kg a.i./ha (POST)
38.8 4534 50822 3.41
T3 : Atrazine 1.25 kg a.i./ha (PRE) fb. Paraquat 1.0 kg
a.i./ha (POST)
32.8 4791 54725 3.56
T4 : Atrazine 1.25 kg a.i./ha (PRE) fb. Paraquat 1.5 kg
a.i./ha (POST)
37.6 4752 52488 3.38
T5 : Atrazine 1.25 kg a.i./ha (PRE) fb. Glyphosate 2.5
kg a.i./ha (POST)
43.6 5305 59139 3.70
T6 : Atrazine 1.25 kg a.i./ha (PRE) fb. Glyphosate 3.0
kg a.i./ha (POST)
35.7 5283 60702 3.76
T7 : Atrazine 1.25 kg a.i./ha (PRE) fb. 2,4-D Na salt
2.0 kg a.i./ha (POST)
34.7 3457 39411 2.90
T8 : Atrazine 1.25 kg a.i./ha (PRE) fb. 2,4-D Na salt
3.0 kg a.i./ha (POST)
38.5 4105 41853
T9 : Atrazine 1.25 kg a.i./ha (PRE) fb. (2IC 30 and 40
DAS) + 1 HW (between 30 and 45 DAS)
40.2 4826 52375 3.25
T10 : Weedy check 30.7 2342 20727 2.23
SEm+ 0.9 1.91 2509 0.12
CD at 5% 2.67 567 7454 0.36
Ramdurg Ishrat, 2010
Table 7 : Yield attributes and economics as influenced by pre and post emergence application
of herbicides in maize

32. Table 8 : weed index, WCE and Grain yield of maize as influenced by
application of herbicides in maize
Treatment Weed
index (%)
WCE
(%)
Grain yield
(t/ha)
T1: Weedy check (no weeding, no intercultivation ) 33.25 0.00 5.13
T2: Mechanical weeding( at 25 DAS and at 45 DAS and IC at 30
DAS )
9.96 27.94 6.94
T3: Atrazine ( 1.00 kg ha—1 pre-em ) + IC at 30 DAS 18.09 16.05 6.31
T4: Atrazine ( 1.25 kg ha—1 pre-em ) + IC at 30 DAS 16.00 18.36 6.49
T5: Atrazine ( 0.75 kg ha—1 pre-em ) fb. 2,4- D ( 1.00 kg ha--1
post- em) at 30 DAS
1.78 28.58 7.57
T6: Oxyfluorfen ( 0.25 kg ha—1
post – em) at 20 DAS
29.37 24.45 5.45
T7: Weed free check ( IC at 20 DAS and 40 DAS + HW at 30 DAS
and 50 DAS)
0.00 36.18 7.72
S. Em± 3.79 0.94 0.29
CD at 5% 11.26 2.79 0.87
MARS, Dharwad Shantveerayya, 2010

33. Treatments Gross
returns
(Rs.ha-1)
Net returns
(Rs.ha-1)
Benefit:
cost ratio
T1: Weedy check ( no weeding, no intercultivation ) 69564 42670 2.59
T2: Mechanical weeding( at 25 DAS and at 45 DAS and IC
at 30 DAS )
94156 64510 3.18
T3: Atrazine ( 1.00 kg ha--1
pre-em ) + IC at 30 DAS
85562 56235 2.92
T4: Atrazine ( 1.25 kg ha--1
pre-em ) + IC at 30 DAS
88048 58371 2.97
T5: Atrazine ( 0.75 kg ha--1
pre-em ) fb. 2,4- D ( 1.00 kg ha--1
post- em) at 30 DAS
102600 72993 3.47
T6: Oxyfluorfen ( 0.25 kg ha--1
post – em) at 20 DAS
73899 44726 2.53
T7: Weed free check ( IC at 20 DAS and 40 DAS + HW at
30 DAS and 50 DAS)
104684 73785 3.39
S. Em± 3985.49 3985.49 0.14
CD at 5% 11841.49 11841.49 0.42
Table 9 : Economics of maize as influenced by application of herbicides
MARS, Dharwad Shantveerayya, 2010

34. Treatments
Total dry weight of
weeds (g m-2)
Weed index
Weed control
efficiency (%)
1.Atrazine 1.00 kg a.i./ha (PRE) 6.69 13.20 50.15
2.Metribuzine 0.25 kg a.i./ha (PRE) 6.71 14.91 50.00
3.Alachlor 0.50 kg a.i./ha + Atrazine 1.0 kg a.i./ha
(PRE)
6.36 11.74 52.62
4.Glyphosate 1.00 kg a.i./ha (PP) fb. Atrazine 375 g
a.i./ha + Alachlor 0.50 kg a.i/ha
8.55 24.01 36.33
5.Glyphosate 1.00 kg a.i./ha (PP) fb. 2, 4-D @ 2.00 kg
a.i./ha (POST)
7.54 19.75 43.83
6.Glyphosate 1.00 kg a.i./ha (PP) + Castor oil 4. ltr/ha 8.18 30.83 39.05
7.Atrazine 1.25 kg a.i./ha (PRE) fb. Atrazine 1.50 kg
a.i./ha (PRE) to weeds
6.03 3.80 55.07
8.Atrazine 1.00 kg a.i./ha fb. 2, 4-D @ 2.0 kg a.i./ha 6.64 12.68 50.52
9.Alachlor 1.00 kg a.i./ha (PRE) fb. Oxyfluorfen 0.20
kg a.i./ha (POSt) directed spray
5.15 12.79 61.62
10.Atrazine 1.50 kg a.i./ha 6.69 13.51 50.15
11.Oxyfluorfen 0.15 kg a.i./ha (PRE) 5.64 22.32 57.96
12.Maize + cover crop (cowpea) 5.97 31.42 55.50
13.Maize + cover cropp (mung bean) 6.55 25.39 51.19
14.Weed free check 1.25 - 90.73
15.Weedy check 13.42 49.73 -
S.Em + 0.44
CD at 5% 1.27
Table10 : Total dry weight, weed control efficiency and weed index in maize as influence by weed control treatment
Shailendra singh, 2011ARS, Arabhavi

35. Treatments
Grain weight
per plant (g)
Grain yield Stover yield
Atrazine 1.00 kg a.i./ha (PRE) 102.97 48.99 70.94
Metribuzine 0.25 kg a.i./ha (PRE) 106.00 47.85 72.81
Alachlor 0.50 kg a.i./ha + Atrazine 1.0 kg a.i./ha (PRE) 108.40 49.12 69.38
Glyphosate 1.00 kg a.i./ha (PP) fb. Atrazine 375 g a.i./ha +
Alachlor 0.50 kg a.i/ha
96.67 42.35 57.40
Glyphosate 1.00 kg a.i./ha (PP) fb. 2, 4-D @ 2.00 kg a.i./ha
(POST)
96.70 44.92 62.81
Glyphosate 1.00 kg a.i./ha (PP) + Castor oil 4. ltr/ha 85.87 38.54 58.44
Atrazine 1.25 kg a.i./ha (PRE) fb. Atrazine 1.50 kg a.i./ha
(PRE) to weeds
110.17 54.02 74.06
Atrazine 1.00 kg a.i./ha fb. 2, 4-D @ 2.0 kg a.i./ha 105.20 48.91 68.13
Alachlor 1.00 kg a.i./ha (PRE) fb. Oxyfluorfen 0.20 kg a.i./ha
(POSt) directed spray
106.50 48.86 68.44
Atrazine 1.50 kg a.i./ha 103.90 48.41 68.44
Oxyfluorfen 0.15 kg a.i./ha (PRE) 97.17 43.16 58.96
Maize + cover crop (cowpea) 84.63 38.34 48.75
Maize + cover cropp (mung bean) 91.80 41.59 60.63
Weed free check 117.67 56.01 76.25
Weedy check 83.67 28.11 45.31
S.Em + 5.22 3.16 2.67
CD at 5% 15.11 9.17 7.73
Table 11: Grain yield and yield components of maize as influenced by weed control treatments
Shailendra singh, 2011ARS Arabhavi

36. Conclusion
Sequential application of herbicides helps to control
weeds on time and for longer period. Pre-emergence application of
atrazine 1.50 kg ha-1/simazine 1-1.5 kg ha -1 helps to control weeds
up to 30 days followed by atrazine 1.50 kg ha-1 (pre-emergence to
weed and post emergence to crop)/2, 4-D @ 1 kg ha-1/ paraquat 1 kg
ha-1 (Directed spray)/glyphosate 0.1 kg ha-1 (Directed spray) control
after the new emerging weeds. This will help the farmer in reducing
the burden of labour problem.

37. FUTURE LINE OF WORK
 Continuous studies are required on the effectiveness and bio-
efficacy of new generation herbicides and herbicide mixtures in
maize crop.
 Studies on residual effect of herbicides on crop grown in sequence
and also on the environment in long-run needs to be initiated.
 The studies are needed on the use of herbicide in granular form.
 Use of different new methods of weed control like electromagnetic
radiations.
 Use of encapsulated herbicides.

38. “Knowledge is like a garden: if it is not cultivated, it
cannot be harvested”